Enhanced photocatalytic activity at multidimensional interface of 1D-Bi2S3@2D-GO/3D-BiOI ternary nanocomposites for tetracycline degradation under visible-light

Fe- and S-Modified BiOI as Catalysts to Oxygen Evolution and Hydrogen Evolution Reactions in Overall Photoelectrochemical Water Splitting

Developing catalysts with superior activity to hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is equally important to the overall photoelectrochemical water splitting to produce hydrogen. In this work, bismuth oxyiodide (BiOI), iron-modified bismuth iodide Fe/BiOI, and the sulfurized S-Fe/BiOI were prepared using the solvothermal method. The three materials all have good absorption ability for visible light. The photoelectrochemical catalytic activity of BiOI to oxygen evolution reaction (OER) is significantly enhanced after iron modification, while the sulfurized product S-Fe/BiOI exhibits better catalytic activity to hydrogen evolution reaction (HER). Hence, OER and HER can be simultaneously catalyzed by using Fe/BiOI and S-Fe/BiOI as anodic and cathodic catalysts to facilitate the overall photoelectrochemical water splitting process.

Fabrication of water-floating litchi-like polystyrene-sphere-supported TiO2/Bi2O3 S-scheme heterojunction for efficient photocatalytic degradation of tetracycline

The exploration of advanced photocatalysts for antibiotic degradation is critical, but it remains a challenge due to the lack of rational structural design and in-depth insights into molecular oxygen activation. Water-floating photocatalysts could be one of the best choices owing to their technical features in terms of reasonability and efficiency involving a high oxygenation of photocatalyst surface, fully solar irradiation, and simple recycling and reuse. Herein, a floatable litchi-like architecture of a polystyrene-sphere-supported TiO2/Bi2O3 (PS@TiO2/Bi2O3) S-scheme heterojunction was skillfully constructed and evaluated for photodegradation of model tetracycline (TC) antibiotics. By integrating the advantages of floatability and S-scheme, the TC removal rate of the optimal PS@TiO2/Bi2O3-0.4 catalyst can reach 88.4% under 1 h illumination, which is higher than that of pristine Bi2O3 (60.8%) and PS@TiO2 (40.1%). Moreover, PS@TiO2/Bi2O3-0.4 exhibits high recyclability and stability, and there is no significant loss of activity after five cycles of repeated use. With the aid of liquid chromatography-mass spectrometry analysis and density functional theory calculations, a reasonable degradation pathway for TC was proposed. The present work provides a recyclable and efficient approach for the photodegradation of TC, expecting to guide the innovative exploitation of other environmental systems.

In-situ monitoring of thiazine molecular aggregation in various solvents via a free-standing acoustic levitator

In this work, we explored the in-situ reaction modeling of the molecular self-aggregation of methylene blue (MB), which is a cationic thiazine dye, in different solvents via a container-less acoustic levitator by floating of a single droplet. Our in-situ spectroscopic study revealed that the dimer essentially has a sandwich structural geometry with a deviation from parallel stacking and horizontal arrangements in the molecular planes. The real time conversion of the monomer in MB into a dimer and their dynamics in water and ethanol media were monitored using a free-standing acoustic levitator droplet system. The absorption spectra revealed changes in the two resolved peaks (monomer and dimer) and orderliness when water and ethanol were used as the media. Interestingly, the enhancement in the dimerization of MB could be attributed to droplet evaporation, which is difficult to observe in typical reactor containers. Moreover, acidic protonation resulted in a change in the aggregation orientation direction of the MB molecules, forming an unusual J-aggregation. Theoretical DFT calculations revealed that MB underwent typical H-aggregation and J-aggregation in the different solvent environments, and their orientations well matched the spectroscopic data.

Bi/BiOI/carbon quantum dots nano-sheets with superior photocatalysis

A new photocatalyst of Bi/BiOI/Carbon quantum dots (CQDs) was synthesized via a simple method. Photocatalytic performance of Bi/BiOI/CQDs was evaluated by photodegradation of RhB. Experiment indicated that the introduction of CQDs could improve the photocatalysis activity of BiOI obviously. Moreover, there is a optimum percentage of CQDs. In this photocatalytic system, the enhanced photoactivity was mainly attributed to the heterojunction interface between CQDs and BiOI, as well as the enhanced light harvesting for the appropriate CQDs introduction. The radicals trapping experiments revealed that O2˙-, ˙OH and h+ were the main active species during the photocatalysis process.

Novel Ag-bridged dual Z-scheme g-C3N4/BiOI/AgI plasmonic heterojunction: Exceptional photocatalytic activity towards tetracycline and the mechanism insight

Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical. Herein, aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers and unstable structure, a novel Ag-bridged dual Z-scheme g-C₃N₄/BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method. Results showed that Ag-AgI nanoparticles and three-dimensional (3D) BiOI microspheres were decorated highly uniformly on the 3D porous g-C₃N₄ nanosheet, resulting in a higher specific surface area and abundant active sites. The optimized 3D porous dual Z-scheme g-C₃N₄/BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline (TC) in water with approximately 91.8% degradation efficiency within 165 min, outperforming majority of the reported g-C₃N₄-based photocatalysts. Moreover, g-C₃N₄/BiOI/Ag-AgI exhibited good stability in terms of activity and structure. In-depth radical scavenging and electron paramagnetic resonance (EPR) analyses confirmed the relative contributions of various scavengers. Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework, fast electron transfer of dual Z-scheme heterojunction, desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas. Therefore, the 3D porous Z-scheme g-C₃N₄/BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation. The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications.

Advanced progress on the significant influences of multi-dimensional nanofillers on the tribological performance of coatings

Over the past two decades, nanofillers have attracted significant interest due to their proven chemical, mechanical, and tribological performances. However, despite the significant progress realized in the application of nanofiller-reinforced coatings in various prominent fields, such as aerospace, automobiles and biomedicine, the fundamental effects of nanofillers on the tribological properties of coatings and their underlying mechanisms have rarely been explored by subdividing them into different sizes ranging from zero-dimensional (0D) to three-dimensional (3D) architectures. Herein, we present a systematic review of the latest advances on multi-dimensional nanofillers for enhancing the friction reduction and wear resistance of metal/ceramic/polymer matrix composite coatings. Finally, we conclude with an outlook for future investigations on multi-dimensional nanofillers in tribology, providing possible solutions for the key challenges in their commercial applications.

Enhanced sulfamethazine detoxification by a novel BiOCl (110)/NrGO/BiVO4 heterojunction

The emerging contaminants removal from the environment has recently been raised concerns due to their presence in higher concentrations. Over usage of emerging contaminant such as sulfamethazine poses serious threat to the aquatic and human health as well. This study deals with rationally structured a novel BiOCl (110)/NrGO/BiVO₄ heterojunction which is used to detoxify sulfamethazine (SMZ) antibiotic efficiently. The synthesised composite was well characterized and the morphological analysis evidenced the formation of heterojunction consisted of nanoplates BiOCl with dominant exposed (110) facets and leaf like BiVO₄ on NrGO layers. Further results revealed that the addition of BiVO₄ and NrGO tremendously increased the photocatalytic degradation efficiency of BiOCl with the rate of 96.9% (k = 0.01783 min^-1) towards SMZ within 60 min of visible light irradiation. Furthermore, heterojunction energy-band theory was employed to determine the degradation mechanism of SMX in this study. The larger surface area of BiOCl and NrGO layers are believed to be the reason for higher activity which facilitates the excellent charge transfer and improved light absorption. In addition, SMZ degradation products identification was carried out by LC-ESI/MS/MS to determine the pathway of degradation. The toxicity assessment was studied using E. coli as a model microorganism through colony forming unit assay (CFU), and the results indicated a significant reduction in biotoxicity was observed in 60 min of degradation process. Thus, our work gives new methods in developing various materials that effectively treat emerging contaminants from the aqueous environment.

In-situ development of boron doped g-C3N4 supported SBA-15 nanocomposites for photocatalytic degradation of tetracycline

In this study, versatile boron-doped graphitic carbon nitride (gCN) incorporated mesoporous SBA-15 (BGS) composite materials were prepared by thermal polycondensation method using boric acid & melamine as a B-gCN source material and SBA-15 as mesoporous support. The prepared BGS composites are utilized sustainably using solar light as the energy source for the continuous flow of photodegradation of tetracycline (TC) antibiotics. This work highlights that the photocatalysts preparation was carried out with an eco-friendly strategy, solvent-free and without additional reagents. To alter the amount of boron quantity (0.124 g, 0.248 g, and 0.49 g) have to prepare three different composites using a similar procedure, the obtained composites viz., BGS-1, BGS-2 and BGS-3, respectively. The physicochemical property of the prepared composites was investigated by X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman, Diffraction reflectance spectra, Photoluminescence, Brunauer-Emmett-Teller and transmission electron microscopy (TEM). The results shows that 0.24 g boron- loaded BGS composites degrade TC up to 93.74%, which is much higher than the rest of the catalyst. The addition of mesoporous SBA-15 incresed the specific surface area of the g-CN, and heteroatom of boron increased the interplanar stracking distance of g-CN, enlarged the optical absorption range, reducing the energy bandgap and enhanced the photocatalytic activity of TC. Additionally, the stability and recycling efficiency of the representative photocatalysts viz., BGS-2 was observed to be good even at the fifth cycle. The photocatalytic process using the BGS composites demonstrated to be capable candidate for the removal of tetracycline biowaste from aquesous media.

Alkali functionalized carbon nitride with internal van der Waals heterostructures: Directional charge flow to enhance photocatalytic hydrogen production

Improving the charge separation and migration in graphitic carbon nitride (CN) is the critical issue to enhance its photocatalytic performance, but still remains very challenging. Herein, the alkali metals were introduced into the interlayer and intralayer of CN to tackle this challenge. The lithium sodium-modifying carbon nitride layer (LiNaCN2) and the adjacent CN layer formed a van der Waals heterostructures (VDWHs), while the potassium-intercalating served as interlayer charge transfer channels to induce the directional charge flow. Experiments and theoretical calculations indicated that such unique construction provided intrinsic driving force to obtain the electrons from LiNaCN2 to CN via directional potassium channels. In accordance with the theoretical prediction, a dramatically red-shift of the light absorption feature was achieved for interlayer potassium-intercalating and intralayer lithium sodium-modifying co-functionalized carbon nitride (LiNaCN-K-CN2) to show narrowed bandgap energy of 2.15 eV. This directional charge flow in CN resulted in the rapid transfer of charge carriers in both interlayer as well as intralayer of CN, which reduced the electronic localization as well as extended the π conjugative effect. Consequently, the LiNaCN-K-CN2 displayed stable and remarkable hydrogen production rate of about 2.46 mmol g^-1 h^-1 with apparent quantum yield (AQY) of about 13.68% at 435 nm, which was 22 folds higher than that of the pristine CN. This finding provides the feasible strategy to precisely tune the directions of charge transfer for high-performance CN-based photocatalysts.

Morphology engineering of defective graphene for microwave absorption

Graphene with abundant defects has been considered as the most lightweight electromagnetic functional materials. Although important, the dominant electromagnetic response of defective graphene with diverse morphologies is rarely the focus of existing research. Herein, the defective graphene with two-dimensional planar structure (2D-ps) and three-dimensional continuous network (3D-cn) morphologies were dexterously designed with 2D mixing and 3D filled systems of polymeric matrix. A comparison between the topologies of defective graphene-based nanofillers and the microwave attenuation behaviors was examined. Defective graphene with 3D-cn morphology can achieve ultralow filling content and broadband absorption, which is attributed to the presence of numerous pore structures that promote impedance matching, induce continuous conduction loss and provide multiple reflection and scattering sites for electromagnetic wave attenuation. Comparatively, by virtue of the increased filling content of 2D-ps, the dielectric losses primarily originate from the dielectric genes, including aggregation-induced-charge transport, abundant defect and dipole polarization, resulting in good microwave absorption at low thickness and low frequency. Therefore, this work provides a pioneering insight into morphology engineering of defective graphene microwave absorbers, and it will guide future exploration of customizing high-performance microwave absorption materials based on graphene-based low-dimensional building blocks.

Construction of direct FeMoO4/g-C3N4-2D/2D Z-scheme heterojunction with enhanced photocatalytic treatment of textile wastewater to eliminate the toxic effect in marine environment

A novel FeMoO₄/g-C₃N₄-2D/2D Z-scheme heterojunction photocatalyst was prepared via wet chemical method. The observed structural morphology of FeMoO₄/g-C₃N₄ reveals the 2D-iron molybdate (FeMoO₄) nanoplates compiled with the 2D-graphitic carbon nitride (g-C₃N₄) nanosheets like structure. The photocatalytic activity of the g-C₃N₄, FeMoO₄, and FeMoO₄/g-C₃N₄ composites were studied via the degradation of Rhodamine B (RhB) as targeted textile dye under visible light irradiation (VLI). The optimal FeMoO₄/g-C₃N₄ (1:3 ratio of g-C₃N₄ and FeMoO₄) composite show an enhanced degradation performance with rate constant value of 0.02226 min^-1 and good stability even after three cycles. Thus, the h+ and O₂^•－are the key radicals in the degradation of RhB under VLI. It is proposed that the FeMoO₄/g-C₃N₄ Z-scheme heterojunction effectively enhances the transfer and separation ability of e^-/h⁺ pairs, by the way increasing the photocatalytic efficiency towards the RhB degradation. Thus, the newly constructed Z-scheme FeMoO₄/g-C₃N₄ heterojunction photocatalyst is a promising material for the remediation of wastewater relevant to elimination of toxic effect in marine environment.

A facile synthesis of visible light driven Ni3V2O8 nano-cube/BiVO4 nanorod composite photocatalyst with enhanced photocatalytic activity towards degradation of acid orange 7

Photocatalysis is one of the promising method to degrade harmful organic pollutants under visible light exposure. In this work, a novel Ni₃V₂O₈/BiVO₄ nanocomposite has been prepared by one-pot hydrothermal method, and investigated through X-ray diffraction, FT-IR, UV-visible diffuse reflectance spectroscopy, scanning and transmission electron microscopy and photoluminescence techniques. Subsequently, the photocatalytic performance of Ni₃V₂O₈/BiVO₄ nanocomposite has been examined by degrading AO7 under visible light illumination. The photocatalytic efficiency of the optimized 1:2 ratio of Ni₃V₂O₈/BiVO₄ nanocomposite photocatalyst is found to be 87% with a rate constant value of 0.03387 min^-1 which are higher than those of other prepared photocatalysts. This nanocomposite exhibits excellent stability even after 3 three cycles, and shows 1.135- and 1.17-times higher photocurrent intensity than pure BiVO₄ and Ni₃V₂O₈ respectively. The mechanism for the degradation of AO7 over Ni₃V₂O₈/BiVO₄ nanocomposite photocatalyst has been proposed.

Novel BiVO4-nanosheet-supported MoS2-nanoflake-heterostructure with synergistic enhanced photocatalytic removal of tetracycline under visible light irradiation

This paper describes a simple in-situ hydrothermal technique for the production of BiVO₄/MoS₂ binary nanocomposites as visible-light-driven catalysts. The as-prepared samples were analyzed by structural, morphological, compositional, optical, surface area, and photocurrent analyses. The lattice fringe spaces at 0.304 nm and 0.612 nm were indexed to the (112) and (002) crystal planes of BiVO₄ and MoS₂, respectively. Antibacterial photocatalytic capabilities were assessed using tetracycline (TC). Consequently, it was observed that the BiVO₄/MoS₂ nanocomposite demonstrated improved antibacterial removal ability compared with the pristine samples. The BiVO₄/MoS₂ nanocomposite exhibited 97.46% removal of TC compared with the pure BiVO₄ (43.76%) and MoS₂ (35.28%) samples within 90 min. Thus, the photocatalytic performance was observed to follow the given order: BiVO₄/MoS₂ nanocomposite > BiVO₄ > MoS₂. The removal of TC after 90 min of irradiation was approximately 97.46%, 96.62%, 95.59%, and 94.45% after the 1st, 2nd, 3rd, and 4th cycles, respectively. Thus, the recycling tests revealed the stability of the photocatalyst, which exhibited a TC removal efficiency of 94.45% without distinct decay, even after the 4th cycle. According to the trapping results, hydroxyl radicals and holes were the key species and demonstrated a greater influence on the photocatalytic performance than superoxide radicals. The increased activity of the BiVO₄/MoS₂ nanocomposite may be attributed to its large surface area and tunable bandgap, which accelerate the charge-transport characteristics of the photocatalytic system. This insight and synergetic effects can provide a new approach for the development of novel heterostructure photocatalysts.

Low temperature energy- efficient synthesis methods for bismuth-based nanostructured photocatalysts for environmental remediation application: A review

Bismuth-based composite materials have unique structural, chemical, optical, and electrical properties that are highly beneficial in Photocatalysis. The layered structure and tunable bandgap properties of the Bismuth-based composites are advantageous for the absorption of solar light efficiently. Also, these properties help the separation and recombination of photogenerated charge carriers, leading to enhancement in the photocatalytic activity. Synthesis of the catalyst at a lower temperature to produce catalyst reduces the production cost and electrical energy consumption. This review provides an overview of the recent development in Bismuth-based composite nanostructured photocatalytic materials, mainly using low-temperature driven synthesis methods. Herein, we have mainly summarized the primarily used low temperature-based synthetic routes, particularly in the temperature range of 50-300 °C for synthesizing Bismuth-based composite materials. In addition to this, the photocatalytic mechanism, the textural, structural, electronic, and photocatalytic properties of the synthesized photocatalysts are discussed. The literature shows that the surface area of the composite Bismuth-based photocatalytic materials synthesized using the low-temperature synthetic route is in the range of 1.5-81 m²/g and can be activated by solar, ultraviolet, and Light Emitting Diode (LEDs) light irradiation based on the synthetic route. Their photocatalytic performance and structural stability are excellent and utilized for several runs. The comprehensive understanding of the low-temperature synthesis of Bismuth-based composite materials for visible light-activated photocatalytic applications provided will be useful for developing photocatalytic materials on an industrial scale due to energy-efficient synthetic routes. Furthermore, the prospects of low temperature-driven Bismuth-based composite synthesis routes are discussed.

A prominent dual heterojunction framed CuWO4/Bi2WO6/MnS ternary NCs for para-chlorophenol degradation, Cr(VI) reduction & toxicity studies

In account of environmental remediation, an ideal photocatalyst was fabricated for the effective treatment of water systems. Herein, dual heterojunctions framed CuWO₄/Bi₂WO₆/MnS nanocomposite (NCs) was synthesized via simple co-precipitation method followed by ultra-sonicated assisted route. The prepared NCs were investigated its photocatalytic degradation performance using para-chlorophenol (4-CP) and reduction of chromium VI (Cr (VI)) under visible light irradiation. The photocatalyst were characterized by various analytical techniques including XRD, HR-TEM, XPS, UV-vis DRS, FE-SEM, EIS, PL, ESR, Raman and N₂ adsorption and desorption studies. The excellent photodegradation of 4-CP was observed within 180 min by the NCs. Similarly, the Cr (VI) reduction was about 97% within 140 min. The effect of pH and influence of different dosage of NCs and 4-CP on the photodegradation efficiency was investigated. The reusability and stability of the NCs was examined over 6 consecutive runs where the XRD and XPS confirm the structural stability of the prepared NCs. The scavenging experiment were carried out to elucidate the mechanism and the active species involved were O^2-• and OH• radicals. The TOC analysis affirmed the complete mineralization of the prepared NCs. The ecotoxicity analysis was carried out to determine the toxicity effect of intermediates using ECOSAR software and the end product toxicity was also evaluated against E. coli and S. epidermis. The end product toxicity study also confirmed that the degraded product was less toxic compared to parent compound. Further, the genotoxicity study was done to understand the environmental impact using allium cepa and results confirms that there are no causes of cytotoxicity & genotoxicity by the prepared NCs. Therefore, the prepared NCs can be economical, efficient with excellent photocatalytic performance and environment friendly.

Synthesis of novel graphene aerogel encapsulated bismuth oxyiodide composite towards effective removal of methyl orange azo-dye under visible light

Development of novel and eco-friendly composite photocatalysts for the efficient removal of contaminants from wastewater is the need of the hour. In this study, visible light responsive novel graphene aerogel/bismuth oxyiodide (GA/BiOI) composite was synthesized via low-temperature solvothermal method. The synthesized GA/BiOI composite was tested for methyl orange (MO) azo-dye degradation under visible light. The graphene aerogel nanosheets were wrapped onto the surface of the each individual BiOI microsphere, which encourages the interconnection charge transfer process. The light absorption properties of GA/BiOI composite were increased with the addition of graphene aerogel. The optimal 5%-GA/BiOI composite displayed higher MO removal efficiency, which is ∼2 fold more than the bare BiOI photocatalyst. This enhanced photocatalytic activity was on account of lower recombination rate of charge carriers, improved light absorption, and the high surface area. In addition, the 5%-GA/BiOI composite showed good stability until 3 cycles without deactivation. The plausible MO degradation mechanism was also proposed over GA/BiOI under visible light. This work provides a new perspective on the design and synthesis of graphene aerogel-based composite for environmental applications.

Novel fabrication of the recyclable MoS2/Bi2WO6 heterostructure and its effective photocatalytic degradation of tetracycline under visible light irradiation

Developing cost-effective and highly effective visible-light-driven photocatalysts for decomposition of organic contaminants has been deliberated as an important and viable strategy for environmental remediation. Herein, MoS₂/Bi₂WO₆ heterostructure photocatalysts were fabricated with excellent visible light absorption performance and efficient electron/hole (e^-/h⁺) separation efficacy. As-prepared all photocatalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high resolution TEM, X-ray photoelectron spectroscopy (XPS). Although photocatalytic experiments were examined by UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence spectroscopy (PL), and transient photocurrent (I-t). Among all the photocatalysts, that synthesized by using the components 10 mg of Bi₂WO₆ with 100 mg of MoS₂ (denoted as MSBW-10), displayed high photocatalytic performance (96.31%) for tetracycline (TC) under visible light irradiation within 90 min. The kinetic rate constant of the MSBW-10 heterostructure was 5.51 and 6.71 times higher than those of MoS₂ and Bi₂WO₆, respectively. Further, radical trapping experiments revealed that ˙OH radicals and holes were the predominant reactive species involved in the photocatalytic course. The recycle tests revealed the stability of the photocatalyst, which exhibited 91.85% TC removal efficacy without obvious decay even after the fourth cycle. Furthermore, the type-II MoS₂/Bi₂WO₆ heterostructure photocatalyst exhibited a slighter band gap with energy band alignments and enhanced visible-light absorption, separation of charge carriers, and good oxidation/reduction capacities. These deeper insights and synergetic effects can afford a new approach for flourishing novel heterostructure photocatalysts.

Bismuth quantum dots anchored one-dimensional CdS as plasmonic photocatalyst for pharmaceutical tetracycline hydrochloride pollutant degradation

Earth abundant metal based plasmonic photocatalysis is one of the most proficient approaches to degrade the emergent organic pollutants in contaminated water. Here, we report that using one-dimensional CdS/zero-dimensional Bi quantum dot (QD) heterostructures (1D/0D CdS/Bi HSs) were obtained via a simple solvothermal reaction. The results specified that the Bi QDs were grown onto CdS NRs through the reduction of Bi³⁺ ions. The Bi modified CdS HSs were employed as a photocatalyst for pharmaceutical pollutant tetracycline degradation and the optimized sample showed the maximum photocatalytic degradation activity of 90% under visible light radiation within 60 min, which is greater than the pure CdS (52%) under identical conditions. Based on the structural characterizations and degradation efficiency, the obtained CdS/Bi is a promising photocatalyst for the treatment of wastewater which contains emerging pollutants such as organic dyes and pharmaceutical antibiotics during the industrial processes. The boosted photocatalytic degradation efficiency is credited to the doped Bi³⁺ species; surface plasmon resonance effect that raised from metallic Bi QDs and proficient photoinduced charge carriers separation.

In-situ Pt nanoparticles decorated BiOBr heterostructure for enhanced visible light-based photocatalytic activity: Synergistic effect

Advanced functional materials for photocatalytic hydrogen (H₂) generation using abundant solar energy are the core of new and renewable energy research. In this paper, we report the in-situ deposition of platinum quantum-sized particles (Pt QDs) on bismuth oxybromide (BBr) 3D marigold flowers with exposed (101)/(110) facets (i.e. BBr-Pt) hierarchies prepared by a simple solvo-thermal method acting as a surfactant/structure stabilizer in the presence of CTAB. Synthesized samples were characterized by a series of analytical techniques. Intimate contact as demonstrated by HRTEM, effect of Pt loading in 3D-BiOBr nanostructure on photocatalytic H₂ production and crystal violet (CV) dye degradation rate under white LED light irradiation was studied. This was greatly improved by loading Pt QDs on BBr, the latter showing the highest photocatalytic activity for BBr-2Pt nanostructure, due to the synergistic effect of quantum-sized Pt nanoparticles and exposed ((101) and (110) planes). The BBr-2Pt nanostructure photocatalysts showed highest H₂ generation of 320.69 μmol g^-1, which is 142 folds larger than bare BBr (2.26 μmol g^-1).

Visible-light-driven indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes heterostructure as an efficient photocatalyst for the tetracycline degradation

The development of excellent photocatalysts is of great significance for the efficient photocatalytic degradation process, however, the low carrier separation efficiency and poor light absorption ability typically limit the performance of photocatalysts. Herein, a visible light responsive heterostructure composed with indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes (InVO₄/Bi₂WO₆) was synthetized through in-situ hydrothermal method. Further, the photocatalytic activity was performed for tetracycline (TC) under visible light illumination. The InVO₄/Bi₂WO₆ heterostructure builds a strong interface between InVO₄ and Bi₂WO₆ to hinder reunion of photoinduced charge carriers, and provides the sensitive agents for the removal of TC. In particular, the InVO₄/Bi₂WO₆ photocatalyst prepared by taking 5.0 mg of Bi₂WO₆ shows the highest degradation of TC about 97.42% in 72 min. The quenching experiments identified that hydroxyl radicals, and holes dominated in the photocatalytic process. Furthermore, the optimized nanocomposite is stable even after four cycles, which exposes the excellent photostability and reusability of the photocatalyst. In addition, a plausible degradation pathway and mechanism of TC over InVO₄/Bi₂WO₆ nanocomposite is also projected.

Immobilization of Halomonas halodurans and Bacillus halodurans in packed bed bioreactor for continuous removal of phenolic impurities in waste water

Phenol is an organic contaminant widely distributed in wastewater. Biodegradation is one of the suitable methods used to remove phenol from the wastewater. In this study, the bacterial laccase and pectinase were analyzed and phenol degradation potential was studied. A total of six bacterial strains were selected and their phenol degrading potentials were studied. Laccase and pectinase producers were screened on substrate agar plates and several strains produced these enzymes in submerged fermentation. Among these enzyme producing strains, strain PD8 and PD22 exhibited potent phenol degrading ability than other strains. These two bacterial strains (Halomonas halodurans PD8 and Bacillus halodurans PD22) exhibited maximum growth in phenol-supplemented culture medium. These two organisms grown well at wide pH values (pH 3.0 and 10.0), survive well between 20 °C and 50 °C, and showed growth between 1 and 10% sodium chloride concentration. The lyophilized enzyme from PD8 and PD22 were immobilized with alginate beads cross liked with divalent cations. At 1% alginate, the binding efficiency was 40.2 ± 2.9% and it improved up to 2.0% concentration (67.5 ± 4.2%) and further increase on alginate concentration affected binding efficiency. Phenol degradation was maximum within 10 h of treatment in the immobilized packed bed column reactor (83.1 ± 3.2%) and colour removal efficiency was maximum at 12 h treatment (82.1 ± 3.9%). After four successive experimental trials more than 40% efficiency was achieved.

Efficient photocatalytic degradation of industrial contaminants by Piper longum mediated ZnO nanoparticles

Piper longum extract as a reducing agent in green synthesis method is used to synthesize ZnO nanoparticles (ZnO-NPs). The impact of the reductant on the structural, optical and surface morphological properties of ZnO-NPs can be analyzed. Piper longum extract has delicately tuned the band gap of ZnO-NPs. Increase in energy band gap indicates an increase in the number of capping molecules in the prepared ZnO nanoparticles. The carbohydrates and proteins not only play a fundamental role in ZnO capping, which is important for its stability, determination and biocompatibility. Thus obtained nanosized ZnO particles are confirmed by the surface morphological studies. Because of various surface interface properties might have different physical-chemical, desorption-adsorption abilities in the direction towards microbes, create different antibacterial performances. S.aureus has maximum inhibition zone of 23 mm and Escherichia coli has minimum inhibition zone of 7 mm. To assess the photocatalytic activity of the prepared ZnO-NPs under UV light irradiation, methyl orange, malachite green and methylene blue dyes were utilized as model contaminants. The degradation efficiency of MG, MB and MO dyes solution is found that 96%, 69% and 48% of degradation efficiency respectively under ultraviolet light irradiation. The properties of synthetic nanopowders suggest that they have important potential for a variety of biochemical and environmental applications.

Detection of trizole contaminated waste water using biocatalyst and effective biodegradation potential of flubendiamide

Flubendiamide is a new class of chemical pesticide with broad spectrum activity against lepidopteran pests. Due to limited approach and high specificity towards various non targeted organisms, the unrestricted application of this pesticide as a prominent alternate for organochlorine and organophosphate pesticides, causing serious environmental pollution. In this study, wastewater was used for the determination of microbial strains and pesticide degrading fungi. Microbial population and flubendiamide resistant fungal strains were characterized using enriched medium. Aerobic bacteria (6.38 ± 0.23 log CFU/mL), nitrifying bacteria (2.73 ± 0.31 CFU/mL), Lactobaillus (0.72 ± 0.03 log CFU/mL), actinomycetes (5.36 ± 0.27 log CFU/mL) and fungi (4.79 ± 0.22 log CFU/mL) were detected. The prominent fungi genera were, Fusarium, Trichoderma, Cladophialophora, Paecilomyces, Talaromyces, Penicillium, Aspergillus, Candida, Phyllosticta, Mycosphaerella, Ochroconis, and Mucor. Minimum inhibitory concentration of the rapidly growing organism (FR04) revealed its ability to tolerate up to 1250 mg/L flubendiamide concentration. Morphological, biochemical and molecular analysis revealed that the strain was Aspergillus terreus FR04. The residual pesticide was detected using a High Performance Liquid Chromatography (HPLC). High performance liquid chromatography analysis revealed that 89 ± 1.9% pesticide removal efficiency was observed in strain FR04 at optimized culture conditions (96 h, pH 6.5, 30 °C and 300 mg/L pesticide concentration). The strain FR04 degraded pollutants from the wastewater and improved water quality. A. terreu sFR04 is an indigenous fungus and has the ability to degrade trizole pesticides from the wastewater significantly.

Infection microenvironment-activated core-shell nanoassemblies for photothermal/chemodynamic synergistic wound therapy and multimodal imaging

The development of intelligent designs of new antibacterial modalities for diagnosing and treating chronic multidrug-resistant bacterial infections is an urgent need, but achieving the precisive theranostic in response to specific inflammatory microenvironments remains a great challenge. This paper describes our work designing and demonstrating infection microenvironment-activated core-shell Gd-doped Bi₂S₃@Cu(II) boron imidazolate framework (Bi₂S₃:Gd@Cu-BIF) nanoassemblies. Upon exposure to a single beam of 808 nm laser, Bi₂S₃:Gd@Cu-BIF nanoassemblies showed exceptional photothermal conversion (η = 52.6%) and produced several cytotoxic reactive oxygen species, such as singlet oxygen and hydroxyl radicals, by depleting the intracellular glutathione and in-situ catalyzing the decomposition of endogenous hydrogen peroxide in the inflammatory microenvironment. The broad-spectrum antibacterial properties of nanoassemblies were confirmed to be effective against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition rate of 99.99% in vitro. Additionally, in vivo wound-healing studies revealed that Bi₂S₃:Gd@Cu-BIF nanoassemblies could serve as an effective wound spray to accelerate healing following MRSA infections via photothermal/chemodynamic (PTT/CDT) synergistic therapy. The effective wound healing rate in the synergistic treatment group was 99.8%, which is higher than the 69.5% wound healing rate in the control group. Furthermore, magnetic resonance and computed tomography dual-modal imaging mediated by Bi₂S₃:Gd@Cu-BIF nanoassemblies also exhibits promising potential as an integrated diagnostic nanoplatform. Overall, this work provides useful insights for developing all-in-one theranostic nanoplatforms for clinical treatment of drug-resistant bacterial infections. STATEMENT OF SIGNIFICANCE: New treatments and effective diagnostic strategies are critical for fighting drug-resistant bacterial infections. Infection microenvironment-activated Bi₂S₃@Cu-BIF nanoassemblies can simultaneously increase eigen temperature and generate cytotoxic reactive oxygen species, such as singlet oxygen and hydroxyl radicals, under near-infrared laser irradiation, achieving the synergistic effect of photothermal and chemodynamic therapy, which has been proven to be highly effective for inhibiting bacterial activity and speeding wound healing from methicillin-resistant Staphylococcus aureus infection. More importantly, the nanoassemblies could enable early precise visualized detection of bacterial abscess using magnetic resonance/computed tomography dual-modal bio-imaging techniques.

Two-step pyrolysis biochar derived from agro-waste for antibiotics removal: Mechanisms and stability

This study used acetone washing biochar (BCA) and nitric-acid washing biochar (BCN) derived from bagasse to remove sulfamethoxazole (SMX) and tetracycline (TC) in water. Higher specific surface area (1119.53 m² g^-1) and graphitization degree can significantly improve decontamination efficacy, of which BCN has the highest SMX and TC sorption capacities (274.63 mg g^-1 and 353.85 mg g^-1). The kinetics, isotherms and characterization analysis indicated O-containing functional group complexation and π-π interaction were dominant mechanisms in the adsorption process. Adsorption stability experiment showed that BCA has better stability with the coexistence of anions and cations. Besides, the enhancement and competitive adsorption from the interaction between soluble organic matter and TC could facilitate TC decontamination. Therefore, bagasse biochar derived from agro-waste has a promising potential for antibiotic contaminants removal from multi-interference conditions and promotes the recycling of waste, thereby achieving harmony between materials and the ecological environment.

Improved visible light photocatalytic degradation of yttrium doped NiMgAl layered triple hydroxides for the effective removal of methylene blue dye

Fabrication of layered triple hydroxides (LTH) is a typical and remarkable approach to produce new functionalities passionately investigated for photocatalytic removal of organic pollutants from industrial wastewater. The hydrothermal method was used to prepare different weight percentages of yttrium (Y) doped NiMgAl LTH. The structural, functional, optical, and morphological properties of the prepared samples were investigated using X-ray diffraction, Fourier transformed-infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, and scanning electron microscopy. The photocatalytic degradation of the different percentages of Y-doped LTH samples were assessed through the photocatalytic degradation of methylene blue dye under the visible light irradiation. When compared to other lower concentrations of Y doping, the photocatalytic degradation efficiency of 1 wt.% Y-doped LTH was higher. Thus, the optimized LTH's improved photocatalytic performance was attributed to increased visible light absorption with low transmission and improved electron-hole separation.

Cr(VI)-imprinted polymer wrapped on urchin-like Bi2S3 for reduced photocorrosion and improved photoreduction of aqueous Cr(VI)

Just like other metal sulfides, the misfortune of photocorrosion and undesired photogenerated electron-hole recombination for Bi₂S₃ was inevitable. In this work, a viable route to reduce photocorrosion of Bi₂S₃ and improve photoreduction of aqueous Cr(VI) was developed via "dressed" a Cr(VI) imprinting polymer (Cr(VI)-IP) on urchin-like Bi₂S₃ (U-Bi₂S₃). Cr(VI)-IP wrapped on the three dimensional U-Bi₂S₃ was implemented by a bulk polymerization. The wrapped Cr(VI)-IP enabled to fast enrich and adsorb Cr(VI) on U-Bi₂S₃ leading to improve the photoreduced efficiency of photogenerated carriers and restrain the photogenerated electron-hole recombination. What's more, Cr(VI)-IP wrapped on U-Bi₂S₃ was just like an "armor" which could support the three dimensional construction of U-Bi₂S₃ from the structural collapse of photocorrosion and retard the direct contact of oxygen and H₂O from the surrounding media. As expected, the obtained U-Bi₂S₃@Cr(VI)-IP exhibited higher photostability, adsorption, photoreduction capacities towards the target Cr(VI) than the bare U-Bi₂S₃. The photocatalytic kinetic constant of U-Bi₂S₃@Cr(VI)-IP was 6 times higher than U-Bi₂S₃. After 3 times recycling uses, the morphology, crystal structure and chemical constitution of U-Bi₂S₃@Cr(VI)-IP were maintained. In addition, the removal efficiency of Cr(VI) by U-Bi₂S₃@Cr(VI)-IP was kept at 58% whereas U-Bi₂S₃ was almost lost to zero.

Recent developments on bismuth oxyhalide-based functional nanomaterials for biomedical applications

Multifunctional bismuth oxyhalide (BiOX, X = F, Cl, Br, and I) nanomaterials have great potential advantages in medical diagnostic and therapeutic applications. Pure BiOX nanomaterials have some limitations such as...

Effect of nonmetals (B, O, P, and S) doped with porous g-C3N4 for improved electron transfer towards photocatalytic CO2 reduction with water into CH4

Photocatalytic conversion of carbon dioxide (CO₂) into gaseous hydrocarbon fuels is an auspicious way to produce renewable fuels in addition to greenhouse gas emission mitigation. In this work, non-metals (B, O, P, and S) doped graphitic carbon nitride (g-C₃N₄) was prepared via solid-state polycondensation of urea for photocatalytic CO₂ reduction into highly needed methane (CH₄) with water under UV light irradiation. The various physicochemical characterization results reveal the successful incorporation of B, O, P, and S elements in the g-C₃N₄ matrix. The maximum CH₄ yield of 55.10 nmol/(mL_H2O.g_cat) over S-doped g-C₃N₄ has been obtained for CO₂ reduction after 7 h of irradiation. This amount of CH₄ production was 1.9, 1.4, 1.7, and 2.4-folds higher than B, O, P and bare g-C₃N₄ samples. The doping of S did not enlarge the surface area and photon absorption ability of the g-C₃N₄ sample, but this significant improvement was evidently due to effective charge separation and migration. The observed results imply that the doping of non-metal elements provides improved charge separation and is an effective way to boost photocatalyst performance. This work offers an auspicious approach to design non-metal doped g-C₃N₄ photocatalysts for renewable fuel production and would be promising for other energy application.

Recent developments on bismuth oxyhalides (BiOX; X = Cl, Br, I) based ternary nanocomposite photocatalysts for environmental applications

Photocatalytic treatment of organic pollutants present in wastewater using semiconductor nanomaterials under light irradiation is one of the efficient advanced oxidation processes. Stable metal oxide (e.g. TiO₂) based semiconductor photocatalytic systems have been mainly investigated for this purpose. Nevertheless, their large band gap (~3.2 eV) makes them inefficient in utilization of visible light portion of solar light leading to a lower degradation efficiency. Investigations have focused on the development of visible light responsive bismuth oxyhalides (BiOX; X = Cl, Br, I), one of the potential nanomaterials with unique layered structure, for efficient absorption of solar light for the degradation of pollutants. However, the rapid recombination rate of photogenerated charge carriers limits their practical applicability. To overcome such drawbacks, the development of BiOX based ternary nanocomposites received significant attention because of their unique structural and electronic properties, improved visible light response and increased separation and transfer rate of photogenerated charge carriers. This review aims to provide a comprehensive overview of the recent developments on bismuth oxyhalides-based ternary nanocomposites for enhanced environmental pollutants decomposition under visible light irradiation. The principles of photocatalysis, synthetic methodologies of bismuth oxyhalides and their characteristics such as heterojunctions formation, improved visible light response and separation rate of charge carriers and the mechanisms for enhanced visible light photocatalytic activity are discussed. In addition, the future prospects on the improvement in the photocatalytic activity of bismuth oxyhalides-based ternary nanocomposites are also discussed. This review could be beneficial for designing new ternary nanocomposites with superior visible light photocatalytic efficiency.

Fabrication of novel AgVO3/BiOI nanocomposite photocatalyst with photoelectrochemical activity towards the degradation of Rhodamine B under visible light irradiation

In the present work, a visible light driven AgVO₃/BiOI nanocomposite photocatalyst with different wt % (1, 2, 3) of AgVO₃ was fabricated by using facile hydrothermal method. Further, the nanocomposite was characterized by FT-IR, XRD, SEM, TEM, EDS, UV-vis DRS, photoluminescence and photoelectrochemical studies. The structural characterization showed nanorods on nanosheet surface. Among different AgVO₃ loaded samples, the photocatalytic efficiency of 1 wt % AgVO₃/BiOI nanocomposite was found to be comparatively higher than the pure BiOI and AgVO₃. The photodegradation rate constant values of pure BiOI, AgVO₃ and 1, 2, 3 wt % AgVO₃/BiOI nanocomposites are 0.006, 0.0033, 0.0255, 0.01575, 0.0116 min^-1 respectively. This enhanced photocatalytic activity was due to the increasing visible light absorption ability and efficient separation of the charge carriers. Thereby, the 1 wt % AgVO₃/BiOI nanocomposite photocatalyst exhibited increased photodegradation activity, photostability and recyclability characteristics. The radical trapping experiment confirmed the role of OH and h⁺ in the photocatalytic degradation of RhB. Based on this, the probable mechanism of degradation of RhB under visible light irradiation has also been proposed. Hence, we believe it could be a promising material that can be employed for the photodegradation of organic pollutants present in wastewater.

Inlaying metal-organic framework derived pancake-like TiO2 into three-dimensional BiOI for visible-light-driven generation of vanillin from sodium lignosulfonate

Pancake-like TiO₂ (M-TiO₂) derived from the metal-organic framework was inlaid into three-dimensional flower-like BiOI through a facile solvothermal method. M-TiO₂ supplies large surface area and mesoporous structure for attachment and transfer of the substrates and products, while BiOI acts as a photosensitizer to absorb visible light and generates electrons and holes. The distinct structure of M-TiO₂/BiOI gives a favorable contact between the two monomers, and promotes the transfer of charge carriers. In conjunction with the proper band positions of M-TiO₂ and BiOI, the efficient separation of electron-hole pairs is attained. Benefiting from the above cooperative effects of M-TiO₂ and BiOI, the performance for the vanillin generation from sodium lignosulfonate (SLS) over M-TiO₂/BiOI composites has a prominent improvement under visible light. Specifically, the yield over optimal M-TiO₂/BiOI sample is about 5.8 mg/g_SLS, obviously superior to that over pristine M-TiO₂ (~1 mg/g_SLS) and BiOI (~1.1 mg/g_SLS). It is found that h⁺ and O₂^- play the key role for vanillin generation from sodium lignosulfonate, and the low vanillin generation under UV-vis light sheds light on that OH is an adverse factor. We hoped that this work could inspire the studies on the photocatalytic valorization of biomass using noble metal-free catalysts.

Application of advanced materials in sonophotocatalytic processes for the remediation of environmental pollutants

Significant advances in various industrial processes have resulted in the discharge of toxic pollutants into the environment. Consequently, it is essential to develop efficient wastewater treatment processes to reduce water contamination and increase recycling/reuse. Photocatalytic degradation is considered as an efficient method for the degradation of toxic pollutants in industrial wastewater. However, the use of photocatalytic approaches is associated with numerous limitations, such as lengthy procedures and the necessity for large amounts of catalysts. Hence, it has been proposed that photocatalysis could be combined with other techniques, including sonolysis, electrochemical, photothermal, microwave, ultrafiltration, and biological reactor. The integration of photocatalysis with sonolysis could be remarkably beneficial for environmental remediation. The combination of these processes has the advantages of using uniformly dispersed catalysts, regeneration of the catalyst surface, improved mass transfer, enhanced surface area due to smaller catalyst particles, and production of more active radicals for the degradation of organic pollutants. In this review, an overview on employing sonophotocatalysis for the removal of toxic organic contaminants from aqueous environments is provided. Additionally, the limitations of photocatalysis alone and the fundamental sonophotocatalytic mechanistic pathways are discussed. The importance of utilizing advanced two-dimensional (2D) semiconductor materials in sonophotocatalysis and the common synthetic approaches for the preparation of 2D materials are also highlighted. Lastly, the review provides comprehensive insights into different materials based on metal oxides, chalcogenides, graphene, and metal organic frameworks (MOFs), which are involved in sonophotocatalytic processes employed for the remediation of environmental pollutants.

Recent progress in transition metal oxide/sulfide quantum dots-based nanocomposites for the removal of toxic organic pollutants

Water is an essential solvent that is extremely necessary for the survival of life. Water pollution due to the increased utilization of water for various processes, including domestic and industrial activities, poses a special threat that contaminates both surface and ground water. In recent years, advanced oxidation processes (AOPs) have been applied to deal with wastewater problems, which is a green method used to oxidize organic contaminants with strong oxidative radical species. Among the AOPs, photocatalytic technology is one of the most promising strategies for wastewater cleaning, which fulfills the aims of environmentally friendly and sustainable development. Owing to their unique electronic, optical, and structural properties, nanoscale semiconductors have received substantial interest as materials for AOPs, particularly inspired by their superb quantum confinement effects and large surface-area-to-volume ratio, which are essential for catalytic reaction kinetics. Recent advancements have revealed that semiconductor nanocrystals, known as quantum dots (QDs), are newly emerging zero-dimensional (0-D) nanomaterials, which have garnered much attention owing to their special physiochemical characteristics such as high conductivity, thermo-chemical and opto-mechanical stability, high adsorption coefficients, and, most importantly, their admirable recyclability. In this review, we provide a clear understanding of the importance of semiconductor QD-based nanocomposites in the degradation of organic pollutants, in addition to the mechanism involved in the reaction process. Following this, the enhancement of different materials, such as metal oxides and metal sulfide QD-based nanocomposites, is discussed in the context of combating environmental pollution.

Solvent-mediated synthesis of BiOI with a tunable surface structure for effective visible light active photocatalytic removal of Cr(VI) from wastewater

The present study investigated the effect of various solvents on the tunable surface morphology and photocatalytic activity (PCA) of bismuth oxyiodide (BiOI), which could be used for the reduction of Cr(VI) under visible light irradiation (VLI). BiOI samples exhibiting different morphologies, i.e., two-dimensional square-like nanosheet and three-dimensional hierarchical flower-like morphology, were synthesized by a hydro/solvothermal process using different solvents, namely H₂O, MeOH, EtOH, and ethylene glycol (EG). The crystal structure, surface morphology, surface area, light-absorption capability, and recombination rate of the photogenerated charge carriers were examined by X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller analysis, UV-vis diffuse reflectance spectroscopy, photoluminescence, and transient photocurrent analyses, respectively. The BiOI sample fabricated in EG showed excellent photocatalytic efficiency (~99%) for the reduction of Cr(VI) after 90 min under VLI. The enhanced PCA demonstrated that the high surface area and well-structured surface characteristics of flower-like 3D BiOI microspheres played important roles in the photoreduction process. Moreover, a plausible mechanism for the reduction of Cr(VI) over the EG-BiOI photocatalyst was proposed. The results of the PCA evaluation and recycle test revealed that 3D EG-BiOI microspheres could serve as promising materials for the efficient removal of Cr(VI) from wastewater. Additionally, EG-BiOI could be utilized in other environmental remediation processes.

Graphene-Based Composites as Catalysts for the Degradation of Pharmaceuticals

The incessant release of pharmaceuticals into the aquatic environment continues to be a subject of increasing concern. This is because of the growing demand for potable water sources and the potential health hazards which these pollutants pose to aquatic animals and humans. The inability of conventional water treatment systems to remove these compounds creates the need for new treatment systems in order to deal with these class of compounds. This review focuses on advanced oxidation processes that employ graphene-based composites as catalysts for the degradation of pharmaceuticals. These composites have been identified to possess enhanced catalytic activity due to increased surface area and reduced charge carrier recombination. The techniques employed in synthesizing these composites have been explored and five different advanced oxidation processes-direct degradation process, chemical oxidation process, photocatalysis, electrocatalyis processes and sonocatalytic/sono-photocatalytic processes-have been studied in terms of their enhanced catalytic activity. Finally, a comparative analysis of the processes that employ graphene-based composites was done in terms of process efficiency, reaction rate, mineralization efficiency and time required to achieve 90% degradation.

In2S3/BiOI composites boost visible-light photocatalytic degradation of tetracycline hydrochloride

In₂S₃/BiOI composites have potential to degrade tetracycline hydrochloride under visible light due to the synergistic effect between In₂S₃ and BiOI.

Enhanced bacterial disinfection by CuI–BiOI/rGO hydrogel under visible light irradiation

Compared with traditional layered graphene, graphene hydrogels have been used to construct highly efficient visible light-excited photocatalysts due to their particular three-dimensional network structure and efficient electron transport capacity. In this work, CuI–BiOI/rGO hydrogel with excellent photocatalytic antibacterial activity was prepared and its activity against Escherichia coli and Staphylococcus aureus was evaluated. The result indicates that CuI–BiOI/rGO hydrogel exhibits superior sterilization performance and higher stability than CuI–BiOI and BiOI/rGO, and could completely kill Escherichia coli and Staphylococcus aureus within 40 min. However, only a small amount of Escherichia coli and Staphylococcus aureus can be inactivated by CuI–BiOI and BiOI/rGO hydrogels. Graphene hydrogel plays a significant part in enhancing the disinfection activity of CuI–BiOI/rGO hydrogel. Furthermore, the synergistic effect between CuI of p-type semiconductors, as a hole transport layer, and graphene hydrogel greatly increases the separation and transfer efficiency of photogenerated electron holes excited by BiOI, and further improves the disinfection activity of CuI–BiOI/rGO hydrogel.

Compared with traditional layered graphene, graphene hydrogels have been used to construct highly efficient visible light-excited photocatalysts due to their particular three-dimensional network structure and efficient electron transport capacity.