A review on visible light driven spinel ferrite-g-C3N4 photocatalytic systems with enhanced solar light utilization

Advanced oxidation process-mediated removal of pharmaceuticals from water: a review of recent advances

Pharmaceutical compounds have raised significant environmental concerns, due to their persistent and non-biodegradable nature. Addressing their presence in the environment has become a priority, leading to the application of various removal treatment techniques. Advanced oxidation processes (AOPs) undoubtedly have emerged as highly effective removal techniques, as evidenced by the growing body of work in this area. This review offers an overview of the recent advances in the development of AOPs for treating pharmaceuticals and their by-products. Current trends and discoveries reported in diverse AOP studies have been scrutinized and are presented. Furthermore, emphasis is placed on the use of TiO2-mediated photocatalysis, which stands out as one of the most explored AOPs for pharmaceutical remediation. Performance aspects of TiO2 photocatalytic treatment are explored and discussed encompassing both commercially available and synthesized TiO2, as well as engineered TiO2-based materials (e.g. activated carbon, polymers, metals and non-metals), all aimed at removal of pharmaceutical compounds from the environment. The review concludes by summarizing key findings and offers insights into directions for future research.

Adsorption and photocatalytic-conjugated activity of a chitosan-functionalized titanate coating for the removal of the drug clonazepam from drinking water

This research evaluated H2TiO7 nanotubes (TiNTs) functionalized with 1 (1TiCN), 5 (2TiCN), and 10 (3TiCN) wt.% of chitosan for the removal of clonazepam by an adsorption/photocatalysis-conjugated method. The samples were immobilized on glass, and their mechanical stability was tested by washings. The functionalization of the samples was verified by the FTIR and DRS techniques. SEM images displayed nanotubes in the samples and thickness of 4.24 μm for the 2TiCN coating. The chemical composition of the 2TiCN coating was obtained by EDS. The XRD patterns evidenced chitosan and titanate phases in the functionalized samples. Furthermore, the 2TiCN coating was evaluated in the removal of clonazepam, reaching 80.79% (4.38 and 49.64% more than the TiNT and commercial TiO2 powders, respectively) after 240 min and being 6.88% more efficient after 4 reuses than the 2TiCN powders. OH- ions were the main oxidizing species found by scavenger tests. The surface area of 2TiCN (168.6 m2/g) was 2 times higher than that of TiNTs, and its bandgap (2.95 eV) was the lowest. Therefore, the 2TiCN coating is an excellent alternative to remove clonazepam.

Synthesis of magnetic NiFe2O4/g-C3N4 heterojunction photocatalysts for boosting dye degradation performance under visible-light irradiation

Water pollution from dyes in wastewater is a critical global issue, as these stable organic dyes resist biodegradation, posing serious threats to aquatic ecosystems. To address this situation, advanced photocatalysts have been developed. Here, NiFe2O4/g-C3N4 was synthesized for the photocatalytic degradation of Rhodamine B (RhB) dye in the presence of H2O2 and visible light. Physicochemical analysis results showed NiFe2O4 nanoparticles dispersed in the g-C3N4 matrix, with an upward trend in the saturation magnetization of CNFx as NiFe2O4 content rose. The surface area of CNF30 was 62.3 m2 g-1, outperforming both NiFe2O4 (23.2 m2 g-1) and g-C3N4 (48.5 m2 g-1). NiFe2O4/g-C3N4 could be reused up to four cycles, and efficiently catalyzed the degradation of nearly 98% RhB dye, showing a decreased rate of up to 95% COD. Through scavenger studies, the main role of ˙OH was demonstrated. Therefore, highly efficient and recyclable NiFe2O4/g-C3N4 can be a potential photocatalyst for degradation of dyes.

Enhanced efficiency and stability in the degradation of triazophosphorus pesticides by Al6Si2O13/WO2.72 nanocomposites through synergistic action of S-scheme heterojunction and oxygen vacancies

The environmental contamination caused by organophosphorus pesticides (for example, triazophos) is an escalating concern. To mitigate this issue, this study introduces a novel Al6Si2O13/WO2.72 (ASO/WO) nanocomposite photocatalyst, which markedly enhances the photocatalytic degradation of triazophos. The optimized nanocomposite material with a 60.0 % ASO loading (60-ASO/WO) achieves a degradation rate of 86.3 % for triazophos within 140.0 min, marginally exceeding 60-ASO/WO3 (72.6 %) and significantly outperforming individual ASO (65.0 %), WO (59.5 %), and WO3 (56.2 %). This catalyst retains 88.9 % of its activity after five cycles, showcasing exceptional efficiency and stability. Additionally, its electrochemical surface area (ECSA, 310.0 cm2), total organic carbon (TOC, removal rate of 73.7 %), photocurrent, and electrochemical impedance are all optimal. X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and theoretical calculations elucidate the critical role of oxygen vacancies and the S-scheme heterojunction in augmenting charge separation and photocatalytic performance, corroborating the synergistic effect of oxygen defects and the S-scheme. While individual factors can enhance photocatalytic activity, their combination results in a more pronounced effect. Liquid chromatography-mass spectrometry (LCMS) identifies the principal degradation intermediates, including 1-phenyl-3-hydroxy-1, 2, 4-triazole, diethyl thiophosphate, and 3, 5, 6-trichloro-2-pyridinol, underscoring the material's potential in environmental remediation.

Interfacial Engineering over Pt-Calcium Ferrite/2D Carbon Nitride Nanosheet p-n Heterojunctions for Superior Photocatalytic Properties

The present study discloses the fabrication of efficient p-n heterojunctions using n-type polymeric bulk carbon nitride (b-CN, E g = 2.7 eV) or exfoliated nanosheets of carbon nitride (NSCN, E g = 2.9 eV) with p-type spinel ferrite CaFe2O4 (CFO, E g = 1.9 eV) for photocatalytic hydrogen generation. A series of p-n combinations were fabricated and characterized by various techniques. The oxide-carbon nitride interactions, light absorption, band alignment at the interface, and water/H3O+ adsorption capability were elucidated over heterojunctions and correlated with the photocatalytic hydrogen yield. The main developments in the present study are as follows: (1) All heterojunctions were more active than pure phases. (2) The photocatalytic activity trend validated an increase in the lifetime of charge carriers from TRPL. Pt(1 wt %)-CFO(1 wt %)/NSCN (481.5 μmol/h/g under ultraviolet (UV)-visible-simulated light, 147.5 μmol/h/g under CFL illumination for 20 h, τavg = 10.33 ns) > Pt-NSCN > Pt-CFO/b-CN > CFO/NSCN > CFO/b-CN > NSCN > Pt/b-CN > mechanical mixture (MM) of 1 wt %CFO + NSCN-MM > 1 wt %CFO + b-CN-MM > CFO > b-CN (τavg = 4.5 ns). (3) Pt-CFO/NSCN was most active and exhibited 250 times enhanced photocatalytic activity as compared to parent bulk carbon nitride, 6.5 times more active than CFO/NSCN, and twice more active than Pt-NSCN. Thus, enhanced activity is attributed to the smooth channelizing of electrons across p-n junctions. (4) NSCN evidently offered improved characteristics as a support and photocatalyst over b-CN. The exfoliated NSCN occupied a superior few-layer morphology with 0.35 nm width as compared to parent b-CN. NSCN allowed 57% dispersion of 6 nm-sized CFO, while b-CN supported 14% dispersion of 7.8 nm-sized CFO particles, as revealed by small-angle X-ray scattering spectroscopy (SAXS). Sizes of 2-4 nm were observed for Pt nanoparticles in the 1 wt %Pt/1 wt % CFO/NSCN sample. A binding energy shift and an increase in the FWHM of X-ray photoelectron spectroscopy (XPS) core level peaks established charge transfer and enhanced band bending on p-n contact in Pt-CFO/NSCN. FsTAS revealed the decay of photogenerated electrons via trapping in shallow traps (τ1, τ2) and deep traps (τ3). Lifetimes τ1 (3.19 ps, 42%) and τ2 (187 ps, 31%) were higher in NSCN than those in b-CN (τ1 = 2.2 ps, 42%, τ2 = 30 ps, 31%), which verified that the recombination reaction rate was suppressed by 6 times in NSCN (k 2 = 0.53 × 1010 s-1) as compared to b-CN (k 2 = 3.33 × 1010 s-1). Deep traps lie below the H+/H2 reduction potential; thus, electrons in deep traps are not available for photocatalytic H2 generation. (5) The role of CFO in enhancing water adsorption capability was modeled by molecular dynamics. NSCN or b-CN both showed very poor interaction with water molecules; however, the CFO cluster adsorbed H3O+ ions very strongly through the electrostatic interaction between calcium and oxygen (of H3O+). Pt also showed a strong affinity for H2O but not for H3O+. Thus, both CFO and Pt facilitated NSCN to access water molecules, and CFO further sustained the adsorption of H3O+ molecules, crucial for the photocatalytic reduction of water molecules. (6) Band potentials of CFO and NSCN aligned suitably at the interface of CFO/NSCN, resulting in a type-II band structure. Valence band offset (VBO, ΔE VB) and conduction band offset (CBO, ΔE CB) were calculated at the interface, resulting in an effective band gap of 1.41 eV (2.9 - ΔE VB = 1.9 - ΔE CB), much lower than parent compounds. The interfacial band structure was efficient in driving photogenerated electrons from the CB of CFO to the CB of NSCN and holes from the VB of NSCN to the VB of CFO, thus successfully separating charge carriers, as supported by the increased lifetime of charge carriers and favorable photocatalytic H2 yield.

Construction of S/g-C3N4@β-Bi2O3 heterojunction and its photocatalytic degradation of toluene in the gas phase

In this paper, a modification of g-C3N4 was carried out by combining non-metal doping with the construction of heterojunctions, and a type II heterojunction composite, S/g-C3N4@β-Bi2O3, was prepared. The phase structure, morphology, elemental composition, valence band structure, and light absorption performance of the photocatalyst were analyzed using characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The performance of the composite photocatalyst in the photocatalytic degradation of gaseous toluene, one of the typical volatile organic compounds (VOCs), under simulated solar light was studied. The effects of preparation conditions, toluene concentration, and recycling on the photocatalytic performance of the composite photocatalyst were investigated. The results show that under the optimal preparation conditions, S/g-C3N4@β-Bi2O3 achieved a degradation efficiency of 74.0% for 5 ppm toluene after 5 h of light irradiation. Although the degradation efficiency decreased to 61.2% after five cycles, it maintained 83% of its initial activity, indicating good stability of the composite photocatalyst. Free radical quenching experiments demonstrated that h+ was the main active species in the photocatalytic degradation of toluene, followed by ·O2-. Based on all experimental results, the migration law of photo-generated charges was analyzed, and a possible photocatalytic mechanism was proposed. In this study, a new material was obtained for the photocatalytic removal of VOCs by improving the photocatalytic properties of g-C3N4.

Photocatalytic degradation of Alizarin Red contaminant using Ag2CrO4@NiFe-LDH composite under visible light irradiation

In this study, Ag2CrO4@NiFe-LDH nanoparticles were synthesized by hydrothermal method for photocatalytic degradation of Alizarin Red (AR) dye. Three composites with different molar percentages were prepared, among which 50%Ag2CrO4@50%NiFe-LDH composite was the best sample with a removal rate of 97.1% in AR degradation. Also, the properties, structure, and characteristics of pure Ag2CrO4 and NiFe-LDH and their composites were determined by XRD, FESEM, FTIR, EDX mapping, and UV-visible analyses. It was found that Ag2CrO4@NiFe-LDH composites with the formation of heterogeneous structure of Z-scheme, in addition to increasing the active sites and increasing the specific surface, decrease the recombination rate of pure Ag2CrO4 and NiFe-LDH. Also, the Box-Behnken design technique, which is one of the most common designs used in response surface methodology, was used to optimize the operating conditions and investigate the effect of 4 independent parameters: catalyst amount, solution concentration, pH, and light intensity. The importance of independent parameters and their interactions were determined by ANOVA. By means of numerical optimization, the optimal values of the selected parameters equal to 1.34 g/L of catalyst, concentration of 16.45 mg/L, pH = 10.74, and light intensity of 15.53 W were obtained as optimal conditions with a desirability coefficient of 1.00 and an absorption value of 89.34%. The closeness of adjusted R2 (0.9838) and predicted R2 (0.9507) values show that this model can be successfully used for prediction.

Photocatalytic removal of ammonia nitrogen from water: investigations and challenges for enhanced activity

Ammonia nitrogen (NH3-N/NH4+-N) serves as a crucial chemical in biochemistry and fertilizer synthesis. However, it is also a toxic compound, posing risks from eutrophication to direct threats to human health. Ammonia nitrogen pollution pervades water sources, presenting a significant challenge. While several water treatment technologies exist, biological treatment, though widely used, has its limitations. Hence, green and efficient photocatalytic technology emerges as a promising solution. However, current monolithic semiconductor photocatalysts prove inadequate in controlling ammonia nitrogen pollution. Therefore, this review focuses on enhancing semiconductor photocatalysts' efficiency through modification, discussing four mechanisms: (1) mono-ionic modification; (2) metallic and non-metallic modification; (3) construct heterojunctions; and (4) enhancement of synergistic effects of multiple technologies. The influencing factors of photocatalytic ammonia nitrogen removal efficiency are also explored. Moreover, the review outlines the limitations of current photocatalytic pollution treatment and discusses future development trends and research challenges. Currently, the main products of ammonia nitrogen removal include NO3-, NO2-, and N2. To mitigate secondary pollution, the green process of converting ammonia nitrogen to N2 using photocatalysis emerges as a fundamental approach for future treatment. Overall, this review aims to deepen understanding of photocatalysis in ammonia nitrogen treatment and guide researchers toward widespread implementation of this endeavor.

Lignin-modified graphitic carbon nitride nanotubes for photocatalytic H2O2 production and degradation of brilliant black BN

As a renewable aromatic compound with enormous production potential, lignin has various potential high-value utilization pathways, but the success achieved in the field of photocatalysis is limited. Herein, this work prepares a new type of photocatalyst by modifying Graphitic Carbon Nitride Nanotubes (CNT) with self-assembled lignin nanospheres for the photocatalytic production of H2O2 and the degradation of azo dyes. Under light conditions, lignin enhances the production of H2O2 through oxygen reduction and collaborates with carbon nitride tubes to generate O2- and 1O2. Furthermore, carbon nitride tubes form electron-rich regions with lignin, promoting the transfer of electrons from adsorbed aromatic pollutants to this region, thereby facilitating their degradation. The experimental results indicate that the addition of 5 % lignin significantly enhances the photocatalytic degradation efficiency of azo dyes, with a degradation rate 1.87 times higher than that of the original carbon nitride tubes. Furthermore, CNL also have excellent degradation ability to pollutants in actual wastewater. This study provides new insights and prospects for the high-value utilization of lignin, enabling it to be used as a photocatalytic co-catalyst to participate in the photocatalytic degradation of environmental pollutants.

A systematic review on Nb2O5-based photocatalysts: Crystallography, synthetic methods, design strategies, and photocatalytic mechanisms

With the increasing popularity of photocatalytic technology and the highly growing issues of energy scarcity and environmental pollution, there is an increasing interest in extremely efficient photocatalytic systems. The widespread immense attention and applicability of Nb2O5 photocatalysts can be attributed to their multiple benefits, including strong redox potentials, non-toxicity, earth abundance, corrosion resistance, and efficient thermal and chemical stability. However, the large-scale application of Nb2O5 is currently impeded by the barriers of rapid recombination loss of photo-activated electron/hole pairs and the inadequacy of visible light absorption. To overcome these constraints, plentiful design strategies have been directed at modulating the morphology, electronic band structure, and optical properties of Nb2O5. The current review offers an extensive analysis of Nb2O5-based photocatalysts, with a particular emphasis on crystallography, synthetic methods, design strategies, and photocatalytic mechanisms. Finally, an outline of future research directions and challenges in developing Nb2O5-based materials with excellent photocatalytic performance is presented.

Experimental and theoretical revealing of piezo-photocatalyst Bi2O2CO3 for degradation of ciprofloxacin in water

In this report, we have attempted to experimentally and theoretically reveal a new piezo-photocatalyst Bi2O2CO3 for efficient removal of ciprofloxacin (CIP) from water. Bi2O2CO3 nanoplates were synthesized to evaluate their photocatalytic (irradiation source: simulated-sunlight), piezocatalytic (irradiation source: ultrasonic) and piezo-photocatalytic (irradiation source: simulated-sunlight and ultrasonic) performances for CIP elimination. Under the condition CCIP = 10 mg/L and Ccatalyst = 1 g/L, the piezo-photodegradation rate constant is obtained as kapp = 0.07811 min-1, which surpasses that of photocatalysis (kapp = 0.04686 min-1) and piezocatalysis (kapp = 0.01233 min-1); this phenomenon manifests an obvious piezo-enhanced photocatalytic behavior in terms of the "1 + 1 > 2" principle. The ultrasonic-induced piezoelectric behavior in Bi2O2CO3 nanoplates and involved piezo-photocatalytic mechanism were theoretically elucidated by density functional theory (DFT) and finite-element method (FEM) studies. Additionally, the effects of various factors on the CIP degradation, decomposition mechanism of CIP and toxicity of the decomposition intermediates were also analyzed.

Visible-light-driven photocatalytic degradation of Rose Bengal and Methylene Blue using low-cost sawdust derived SnO2 QDs@g-C3N4/biochar nanocomposite

Conversion of carbon-rich waste biomass into valuable products is an environmentally sustainable method. This study accentuates the synthesis of novel SnO2 QDs@g-C3N4/biochar using low-cost sawdust by applying the pyrolysis method. Morphology, structure, and composition of the synthesized SnO2 QDs@g-C3N4/biochar nanocomposite were characterized using SEM (scanning electron microscope), TEM (transmission electron microscope), XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), FT-IR (infrared spectroscopy) and PL (photoluminescence) spectroscopy. The average diameter of the SnO2 QDs was measured from TEM and found to be 6.79 nm. Optical properties of the as-synthesized SnO2 QDs@g-C3N4/biochar were characterized using UV-visible spectroscopy. The direct band gap of synthesized SnO2 QDs@g-C3N4/biochar nanocomposite was calculated from Tauc's plot and found to be 2.0 eV. The fabricated SnO2 QDs@g-C3N4/biochar photocatalyst exhibited outstanding photocatalytic degradation efficiency for the removal of Rose Bengal (RB) and Methylene Blue (MB) dye through the Advanced Oxidation Process (AOP). The synthesized photocatalyst showed a degradation efficiency of 95.67% for the removal of RB under optimum conditions of 0.3 mL H2O2, photocatalyst dosage of only 0.06 gL-1, and 15 ppm initial RB concentration within 80 min, and 94.5% for the removal of MB dye with 0.5 mL of H2O2, 0.08 gL-1 of the fabricated photocatalyst and 6 ppm of initial MB concentration within 120 min. The photodegradation pathway followed the pseudo-first-order reaction kinetics with a rate constant of 0.00268 min-1 and 0.00163 min-1 for RB and MB respectively. The photocatalyst can be reused up to the 4th cycle with 80% efficiency.

Effective adsorptive removal of sulfamethoxazole (SMX) from aqueous solution by ZIF-8 derived adsorbent ZC-0.5

Efficient removal of antibiotics from the aquatic environment is urgently needed due to their obstinate accumulation and non-biodegradability. In this study, a mesoporous carbon material (ZC-0.5) was successfully synthesized for the adsorption of sulfamethoxazole (SMX), one of the major antibiotics for the treatment of human and animal infections. ZIF-8 as the precursor of ZC-0.5, specifically, using cetyl trimethyl ammonium bromide (CTAB) and sodium laurate (SL) as dual templates and carbonizing at 800 ℃. This novel adsorbent exhibited a high proportion of mesopore (75.64%) and a large specific surface area (1459.73 m²·g^-1). The adsorption experiment examined the reusability of ZC-0.5 and that it could retain superior maximum adsorption capacities (167.45 mg∙L^-1) after five cycles of adsorption and desorption. The adsorption process satisfied the pseudo-second-order kinetic (PSO) and mixed first- and second-order kinetic (MOE). It also satisfied the Freundlich and Sips isotherm models. Moreover, thermodynamic calculation indicated the adsorption process was spontaneous, endothermal, and entropy-increasing. Furthermore, plausible adsorption mechanisms were explained through van der Waals force, electrostatic interaction, hydrophobic force, π-π interaction, and hydrogen bond. This work offers a new efficient adsorbent for antibiotic elimination.

Bismuth Vanadate Decked Polyaniline Polymeric Nanocomposites: The Robust Photocatalytic Destruction of Microbial and Chemical Toxicants

Functional materials have long been studied for a variety of environmental applications, resource rescue, and many other conceivable applications. The present study reports on the synthesis of bismuth vanadate (BiVO₄) integrated polyaniline (PANI) using the hydrothermal method. The topology of BiVO₄ decked PANI catalysts was investigated by SEM and TEM. XRD, EDX, FT-IR, and antibacterial testing were used to examine the physicochemical and antibacterial properties of the samples, respectively. Microscopic images revealed that BiVO₄@PANI are comprised of BiVO₄ hollow cages made up of nanobeads that are uniformly dispersed across PANI tubes. The PL results confirm that the composite has the lowest electron-hole recombination compared to others samples. BiVO₄@PANI composite photocatalysts demonstrated the maximum degradation efficiency compared to pure BiVO₄ and PANI for rhodamine B dye. The probable antimicrobial and photocatalytic mechanisms of the BiVO₄@PANI photocatalyst were proposed. The enhanced antibacterial and photocatalytic activity could be attributed to the high surface area and combined impact of PANI and BiVO₄, which promoted the migration efficiency of photo-generated electron holes. These findings open up ways for the potential use of BiVO₄@PANI in industries, environmental remediation, pharmaceutical and medical sectors. Nevertheless, biocompatibility for human tissues should be thoroughly examined to lead to future improvements in photocatalytic performance and increase antibacterial efficacy.

Synthesis and visible-light photocatalytic property of spinel CuAl2O4 for vehicle emissions

Photodegradation of vehicle emissions is a promising approach for dealing with atmospheric pollution in road tunnels. In this research, copper aluminate nanoparticles (CuAl₂O₄) were prepared by the sol-gel method using copper nitrate, aluminum nitrate, and citric acid as precursor materials. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy to validate their structure, surface morphology, and optical properties, respectively. The XRD and SEM results confirm that the CuAl₂O₄ powder has a particle size of 20-37 nm and exhibits a spinel-type structure. The upper limit of the stimulation wavelength in the UV-Vis diffuse reflectance spectrum is located at 725 nm with a band gap (Eg) of about 1.50 eV, which is suitable for effective visible-light degradation. Photocatalytic performance of the CuAl₂O₄ nanoparticles was analyzed by investigating the effects of light source, calcination temperature, and catalyst loading amount on the degradation of vehicle emissions (CO, HC, and NO). Best results were obtained under fluorescent light irradiation by CuAl₂O₄ nanoparticles calcined at 700 °C. The optimum catalyst amount for decomposing CO, HC, and NO were determined as 0.5 g, 0.5 g, and 2 g, respectively. Overall, the photocatalytic performance study verifies that spinel CuAl₂O₄ photocatalyst is a valuable material for next-generation technologies aimed at reducing harmful emissions from vehicles.

Synergistic Effects of Magnetic Z-Scheme g-C3N4/CoFe2O4 Nanofibres with Controllable Morphology on Photocatalytic Activity

The rational design of interfacial contacts plays a decisive role in improving interfacial carrier transfer and separation in heterojunction photocatalysts. In Z-scheme photocatalysts, the recombination of photogenerated electron-hole pairs is prevented so that the redox capacity is maintained. Here, one-dimensional graphitic carbon nitride (g-C₃N₄)/CoFe₂O₄ fibres were synthesised as a new type of magnetic Z-scheme visible-light photocatalyst. Compared with pure g-C₃N₄ and CoFe₂O₄, the prepared composite photocatalysts showed considerably improved performance for the photooxidative degradation of tetracycline and methylene blue. In particular, the photodegradation efficiency of the g-C₃N₄/CoFe₂O₄ fibres for methylene blue was approximately two and seven times those of g-C₃N₄ and CoFe₂O₄, respectively. The formation mechanism of the Z-scheme heterojunctions in the g-C₃N₄/CoFe₂O₄ fibres was investigated using photocurrent spectroscopy and electrochemical impedance spectroscopy. We proposed that one of the reasons for the improved photodegradation performance is that the charge transport path in one-dimensional materials enables efficient photoelectron and hole transfer. Furthermore, the internal electric field of the prepared Z-scheme photocatalyst enhanced visible-light absorption, which provided a barrier for photoelectron-hole pair recombination.

Recent advances in spinel ferrite-based magnetic photocatalysts for efficient degradation of organic pollutants

Although spinel ferrite (MFe₂O₄, M = Zn, Ni, Mn, etc.) has been reported as a promising catalyst, its low photocatalytic activity under visible light greatly restricts its practical application. Spinel ferrite-based photocatalytic composites have exhibited improved efficiency for pollutant degradation, due to interface charge carrier mobility and structural modification. Meanwhile, due to its magnetism and stability, spinel ferrite composite can be easily recycled for long-term utilization, showing its high application potential. In this review, the recent advances in the construction and photocatalytic degradation of spinel ferrite composites are discussed, with an emphasis on the relationship between structural property and photocatalytic activity. In addition, to improve their photocatalytic application, the challenges, gaps and future research prospects are proposed.

Synergistic removal of organic pollutants from water by CTF/BiVO4 heterojunction photocatalysts

Herein, a series of covalent triazine framework/bismuth vanadate (CTF/BiVO₄) heterojunction catalysts were prepared using the hydrothermal method. The mechanism of the CTF/BiVO₄ heterojunction photocatalyst in the system was examined to provide a theoretical basis for constructing a high-efficiency photocatalysis composite system for removing organic pollutants from water. Compared with CTF and BiVO₄ catalysts alone, composite materials have been shown to have significantly higher degradation efficiencies against organic pollutants in water. Moreover, the degradation effect was found to be optimal when the mass ratio of CTF to BiVO₄ was 1:1 (1-CTF/BiVO₄). On the basis of physicochemical characterization results, it was concluded that the effective construction of CTF/BiVO₄ composite photocatalyst material systems and the formation of type II heterojunction structures between CTF and BiVO₄ effectively promote the separation of photogenerated carriers and increase the interface charge transfer efficiency.

Engineered g-C3N5-Based Nanomaterials for Photocatalytic Energy Conversion and Environmental Remediation

Photocatalysis plays a vital role in sustainable energy conversion and environmental remediation because of its economic, eco-friendly, and effective characteristics. Nitrogen-rich graphitic carbon nitride (g-C₃N₅) has received worldwide interest owing to its facile accessibility, metal-free nature, and appealing electronic band structure. This review summarizes the latest progress for g-C₃N₅-based photocatalysts in energy and environmental applications. It begins with the synthesis of pristine g-C₃N₅ materials with various topologies, followed by several engineering strategies for g-C₃N₅, such as elemental doping, defect engineering, and heterojunction creation. In addition, the applications in energy conversion (H₂ evolution, CO₂ reduction, and N₂ fixation) and environmental remediation (NO purification and aqueous pollutant degradation) are discussed. Finally, a summary and some inspiring perspectives on the challenges and possibilities of g-C₃N₅-based materials are presented. It is believed that this review will promote the development of emerging g-C₃N₅-based photocatalysts for more efficiency in energy conversion and environmental remediation.

Investigation on the role of graphene-based composites for in photocatalytic degradation of phenol-based compounds in wastewater: a review

The ineptitude of conventional water management systems to eradicate noxious compounds leads to the development of advanced treatment systems. The disclosure of graphene-based photocatalytic degradation for the eradication of phenolic compounds has become the "apple of the eye" for many researchers. This review article describes the advanced research progress during the period of 2008-2021 in graphene-based nanocomposites and discusses their different synthesis methods. We will also talk about the applications of nanocomposite in water splitting, dye degradation, solar fuel generations, and organic transformations. Multicomponent heterojunction structure, co-catalyst cohering, and noble metal coupling have been inspected to enhance the photocatalytic performance of graphene-based composite by increasing charge separation and stability. The photocatalytic system's remarkable stability has been described in terms of facile recyclability. The adsorption ability of phenolic compounds has been addressed in the form of Langmuir and Freundlich adsorption isotherm with various factors (pH, concentration, the intensity of light, the effect of catalyst, the effect of time, etc.). The purpose of this review is to survey mechanisms and processes that enlist graphene-based composite in terms of efficacy and dose of catalyst required to attain 99% degradation. Nanoparticles may cause toxicity and a pretext for their toxicity has been mentioned. Finally, it is anticipated that this article could allocate consequential knowledge to fabricating graphene-based composites that are in crucial demand of being discussed in future research.