Novel Cu₂O quantum dots coupled flower-like BiOBr for enhanced photocatalytic degradation of organic contaminant

Enhanced d-π overlap in a graphene supported Ni/PtNi heterojunction for efficient seawater hydrogen evolution

d-π overlap, which represents overlap between metal-d and graphene-π orbitals to facilitate electron transfer, has rarely been reported. Ni/PtNi-G2 exhibits exceptional performance in seawater hydrogen evolution due to the electron-rich surface on Pt resulting from enhanced d-π overlap and subsequent electron transfer from graphene and Ni to Pt.

Cu2O/SrTi1-xCrxO3 Heterojunction Photocatalyst for the Efficient Degradation of Isopropanol under Visible Light Irradiation

A heterojunction of Cu₂O and Cr-doped SrTiO₃ (SrTi_1-xCr_xO₃) was designed for selective photocatalytic isopropanol (IPA) oxidation under visible light irradiation. The photocatalytic oxidation of IPA was measured in a fixed-bed reactor. Cr dopants can increase the light absorption and improve the activity of the catalyst. The formation of the Cu₂O/SrTi_1-xCr_xO₃ heterojunction can further broaden the absorption range of lights and dramatically increase the photocatalytic activity for selective oxidation of IPA. The 3% Cu₂O/SrTi_0.99Cr_0.01O₃ catalyst can fully convert ∼1000 ppm IPA under illumination in 2 h. The selectivity of acetone is ∼100%. The yield is 83 and 4 times higher than that using SrTiO₃ and SrTi_0.99Cr_0.01O₃ as catalysts, respectively. By measuring the ultraviolet-visible absorption spectra and Mott-Schottky plots, we obtained the band structure of the heterojunction, which shows that the conduction and valence bands of Cu₂O are higher than those of SrTi_1-xCr_xO₃, therefore facilitating the separation and transfer of photogenerated electrons and holes. In addition, electron paramagnetic resonance spectroscopy and radical trapping tests reveal that the generation of hydroxyl and superoxide leads to photocatalytic oxidation of IPA by the heterojunction photocatalyst.

A Critical Study of Cu2O: Synthesis and Its Application in CO2 Reduction by Photochemical and Electrochemical Approaches

Copper oxide (Cu2O) is a potential material as a catalyst for CO2 reduction. Cu2O nanostructures have many advantages, including interfacial charge separation and transportation, enhanced surface area, quantum efficiency, and feasibility of modification via composite development or integration of the favorable surface functional groups. We cover the current advancements in the synthesis of Cu2O nanomaterials in various morphological dimensions and their photochemical and electrochemical applications, which complies with the physical enrichment of their enhanced activity in every application they are employed in. The scope of fresh designs, namely composites or the hierarchy of copper oxide nanostructures, and various ways to improve CO2 reduction performance are also discussed in this review. Photochemical and electrochemical CO2 transformations have received tremendous attention in the last few years, thanks to the growing interest in renewable sources of energy and green facile chemistry. The current review provides an idea of current photochemical and electrochemical carbon dioxide fixing techniques by using Cu2O-based materials. Carboxylation and carboxylative cyclization, yield valuable chemicals such as carboxylic acids and heterocyclic compounds. Radical ions, which are induced by photo- and electrochemical reactions, as well as other high-energy organic molecules, are regarded as essential mid-products in photochemical and electrochemical reactions with CO2. It has also been claimed that CO2 can be activated to form radical anions.

WO3/Ag2CO3 Mixed Photocatalyst with Enhanced Photocatalytic Activity for Organic Dye Degradation

The development of an efficient photocatalyst with superior activity under visible light has been regarded as a significant strategy for pollutant degradation and environmental remediation. Herein, a series of WO₃/Ag₂CO₃ mixed photocatalysts with different proportions were prepared by a simple mixing method and characterized by XRD, SEM, TEM, XPS, and DRS techniques. The photocatalytic performance of the WO₃/Ag₂CO₃ mixed photocatalyst was investigated by the degradation of rhodamine B (RhB) under visible light irradiation (λ > 400 nm). The photocatalytic efficiency of the mixed WO₃/Ag₂CO₃ photocatalyst was rapidly increased with the proportion of Ag₂CO₃ up to 5%. The degradation percentage of RhB by WO₃/Ag₂CO₃-5% reached 99.7% within 8 min. The pseudo-first-order reaction rate constant of WO₃/Ag₂CO₃-5% (0.9591 min^-1) was 118- and 14-fold higher than those of WO₃ (0.0081 min^-1) and Ag₂CO₃ (0.0663 min^-1). The catalytic activities of the mixed photocatalysts are not only higher than those of the WO₃ and Ag₂CO₃ but also higher than that of the WO₃/Ag₂CO₃ composite prepared by the precipitation method. The activity enhancement may be because of the easier separation of photogenerated electron-hole pairs. The photocatalytic mechanism was investigated by free radical capture performance and fluorescence measurement. It was found that light-induced holes (h⁺) was the major active species and superoxide radicals (·O₂ ^-) also played a certain role in photocatalytic degradation of RhB.

Floating ZnO QDs-Modified TiO2/LLDPE Hybrid Polymer Film for the Effective Photodegradation of Tetracycline under Fluorescent Light Irradiation: Synthesis and Characterisation

In this work, mesoporous TiO₂-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO₂. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O₂^●−. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).

Metal-organic frameworks derived C/TiO2 for visible light photocatalysis: Simple synthesis and contribution of carbon species

A series of in-situ carbon-doped TiO₂ (C_x/TiO₂) composites with a porous and crystalline structure were successfully synthesized via one-step and low-temperature calcination of titanium metal-organic framework (MOF), MIL-125(Ti). The resultant materials were comprehensively investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), N₂ adsorption-desorption measurements, UV-vis diffuse reflectance spectrum (DRS), photoluminescence (PL) spectra and photoelectrochemical measurements, and their photocatalytic activities for bisphenol A (BPA) degradation were assessed. Compared with the benchmark TiO₂ photocatalyst (P25), the C_x/TiO₂ composite material with high specific surface, lower band gap, and reduced photogenerated electron hole ratio exhibited outstanding photodegradation activity and durability for BPA, which could be attributed to the combined effect of co-doping of multiple carbon species (substituent carbon and carbonate) and porous structure. During BPA degradation, the holes and superoxide radicals were the primary role oxidative species in the reaction process. Therefore, this new efficient photocatalyst is promising candidate for photodegradation of organic pollutants.

In-situ synthesis of Cu2O on cotton fibers with antibacterial properties and reusable photocatalytic degradation of dyes

In this study, the cotton fabrics/cuprous oxide-nanocellulose (Cu₂O-NC) flexible and recyclable composite material (COCO) with highly efficient photocatalytic degradation of dyes and antibacterial properties was fabricated. Using flexible cotton fabrics as substrates, Cu₂O were in-situ synthesized to make Cu₂O uniformly grew on cotton fibers and were wrapped with NC. The photocatalytic degradation ability of COCO-5 was verified by use methylene blue (MB), the degradation rate was as high as 98.32%. The mechanism of COCO-5 photocatalysis and the process of dye degradation were analyzed by using electron paramagnetic resonance (EPR) spectrum, transient photocurrent response (TPR) spectrum, Fourier transform infrared (FTIR) spectroscopy and ion chromatography (IC). This study analyzed the complete path from electron excitation to dye degradation to harmless small molecules. Qualitative and quantitative experiments demonstrate that COCO-5 has high antibacterial activity against S. aureus and E. coli, the highest antibacterial rate can reach 93.25%. Finally, the stability of COCO-5 was verified by recycling and mechanical performance tests. The textile-based Cu₂O functionalized material has photocatalytic degradation and antibacterial properties, and the preparation process is simple and convenient for repeated use, so it has great potential in wastewater treatment containing dyes and bacteria.

Construction of a novel Cu2(OH)3F/g-C3N4 heterojunction as a high-activity Fenton-like catalyst driven by visible light

Inhibiting the competitive effect of O₂ in copper-based Fenton reagents and improving the photogenerated electron–hole pair separation of g-C₃N₄ are the focus of current research.

Fabrication of Dandelion-like p-p Type Heterostructure of Ag2O@CoO for Bifunctional Photoelectrocatalytic Performance

A novel three-dimensional purple dandelion-like hierarchical Ag₂O@CoO heterojunction with an appropriate redox potential was constructed by chemical precipitation of Ag₂O nanoparticle on flower-like CoO. By feat of this hierarchical structure, the Ag₂O@CoO photocathode showed significantly high photoelectroreduction activities toward p-nitrophenol (p-NP) and Cr(VI). The high performance of Ag₂O@CoO was mainly attributed to the specific structural characteristics and synergistic effect of each chemical component. This hierarchical structure could effectively increase the specific surface area, provide more exposed active edges, and be beneficial for multiple light reflection/scattering channels and light utilization efficiency. The introduction of Ag₂O optimized the composition and further improved the band structure, resulting in an improved separation of photogenerated electrons and holes. The unique photocathode achieves a removal efficiency of 86% for photoelectrocatalytic p-NP degradation after 120 min and 95% for Cr(VI) after 40 min under visible light irradiation with excellent stability. This research provided a simple way for the synthesis of photoelectrocatalytic material with potential applications in the field of environmental governance with visible light illumination.

Photoredox Organic Synthesis Employing Heterogeneous Photocatalysts with Emphasis on Halide Perovskite

Lately, heterogeneous semiconductor materials have been explored as an emerging type of efficient photocatalyst for photoredox organic synthesis. Among these semiconductors, lead halide perovskite materials demonstrate unique properties towards excellent charge separation and charge transfer, extremely long charge carrier migration, high efficiency in visible light absorption, and long excited states lifetimes, etc., as proved in ground-breaking solar cell applications, garnering necessary merits for an efficient catalytic system for photoredox organic reactions. Here, the latest progress in heterogeneous semiconductor materials towards this endeavor is examined, with particular emphasis on lead halide perovskite nanocrystals (NCs) in photocatalytic organic synthesis.

Multidimensional assembly of oxygen vacancy-rich amorphous TiO2-BiOBr-sepiolite composite for rapid elimination of formaldehyde and oxytetracycline under visible light

Herein, a novel oxygen vacancy-rich amorphous TiO₂-BiOBr-sepiolite composite was synthesized through a facile one-pot solvothermal method. Under visible light, it exhibited enhanced adsorption and photocatalytic removal activity towards gaseous formaldehyde, whose reaction rate constant is nearly 11.75, 3.44, 1.69, 2.18 and 6.27 times higher than those of amorphous TiO₂, BiOBr, TiO₂-BiOBr, oxygen vacancy-poor composite and P25, respectively. Moreover, it also displayed significantly improved photodegradation performance towards oxytetracycline under visible light. The improved photocatalytic activity is mainly ascribed to the synergy between the ternary heterogeneous structure and introduced oxygen vacancy, leading to the superior adsorption performance, extended visible-light adsorption scope and faster carriers' separation rate. The photogenerated holes are the dominant active species during the reaction process. Additionally, a plausible photocatalytic degradation pathway for oxytetracycline was also proposed. In general, this work provides a viable strategy of visible-light-driven photocatalyst for practical environmental remediation of indoor volatile organic compounds (VOCs) and pharmaceuticals and personal care products (PPCPs).

The Effect of AgInS2, SnS, CuS2, Bi2S3 Quantum Dots on the Surface Properties and Photocatalytic Activity of QDs-Sensitized TiO2 Composite

The effect of type (AgInS2, SnS, CuS2, Bi2S3) and amount (5, 10, 15 wt%) of quantum dots (QDs) on the surface properties and photocatalytic activity of QDs-sensitized TiO2 composite, was investigated. AgInS2, SnS, CuS2, Bi2S3 QDs were obtained by hot-injection, sonochemical, microwave, and hot-injection method, respectively. To characterize of as-prepared samples high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis spectroscopy and photoluminescence (PL) emission spectroscopy were applied. The size of AgInS2, SnS, CuS2, Bi2S3 QDs were 12; 2–6; 2–3, and 1–2 nm, respectively. The QDs and QDs-sensitized TiO2 composites obtained have been tested in toluene degradation under LEDs light irradiation (λmax = 415 nm and λmax = 375 nm). For pristine QDs the efficiency of toluene degradation increased in the order of AgInS2 < Bi2S3 < CuS < SnS under 375 nm and AgInS2 < CuS < Bi2S3 < SnS under 415 nm. In the presence of TiO2/SnS QDs_15% composite, 91% of toluene was degraded after 1 h of irradiation, and this efficiency was about 12 higher than that for pristine QDs under 375 nm. Generally, building the TiO2/AgInS2 and TiO2/SnS exhibited higher photoactivity under 375 nm than the pristine TiO2 and QDs which suggests a synergistic effect between QDs and TiO2 matrix.

Dual-functional Ag3PO4@palygorskite composite for efficient photodegradation of alkane by in situ forming Pickering emulsion photocatalytic system

Removal of oil from water is highly imperative, because of the worldwide oil-contaminated water caused by industrial development and oil spill accidents. As a solution to meet the demand for clean energy technology, photocatalysis has drawn great attention recently. However, a major problem encountered in photodegrading oil is the difficult availability of oil by photocatalyst. To overcome this problem, a novel concept of integrating Pickering emulsification of palygorskite (PAL) clay particles with photocatalytic activity of Ag₃PO₄ is proposed in this work. By a simple co-precipitation method, Ag₃PO₄@PAL composite was prepared and used for the simultaneous emulsification and decomposition of tetradecane. Via a simple Pickering emulsion-based photocatalytic system, Ag₃PO₄ could contact with tetradecane directly, which effectively overcomes the agglomeration and settlement of Ag₃PO₄ in aqueous phase. This in situ photocatalytic system shows a higher efficiency for photodegradation of tetradecane, comparing with traditional solution-dispersed photocatalytic system. Under visible-light irradiation, the removal efficiency of tetradecane is 4.9 times higher than Ag₃PO₄ alone. Direct contact of Ag₃PO₄ with oil pollutes and sufficiently large active surface area greatly improve the efficiency of photodegrading oil. This study provides a new and simple strategy for oil photodegradation via an in situ Pickering emulsion system.

Surface oxygen vacancies enriched FeOOH/Bi2MoO6 photocatalysis- fenton synergy degradation of organic pollutants

To achieve rapid separation of photogenerated charges, increase photocatalytic degradation activity, a visible light-driven FeOOH/Bi₂MoO₆-OVs photocatalyst was designed and successfully fabricated via solvothermal synthesis and calcination. H₂O₂ was added under visible light irradiation to form a heterogeneous photocatalysis-Fenton synergy system. Using visible light irradiation, 10% FeOOH/Bi₂MoO₆-OVs had the best degradation activity. The removal efficiency of phenol was 100% within 3 h, which was 1.54 times and 1.33 times of the degradation efficiency of photocatalysis and Fenton alone, respectively. The catalyst has high removal activity for various pollutants and good cycle stability. Hydroxyl radicals and superoxide radicals have proven to be the main active substances and a reasonable catalytic mechanism was proposed. Surface oxygen vacancy can not only reduce the width of band gap, promote the separation and migration of photogenerated electron-hole pairs, but also make the OO bond of H₂O₂ elongate and weaken, making it easier to react with FeOOH and realize the synergistic effect of photocatalysis-Fenton. Simultaneously, the oxygen vacancies located near the valence band can capture holes, and the holes are rapidly transferred to the surface of the catalyst and participated in the degradation of pollutants.

Green synthesis of Opuntia-derived carbon nanodots for the catalytic decolourization of cationic dyes

Carbon nanodots, rich in functional groups and synthesised using green precursors, catalyse the decolourization of dyes under mild conditions.

Bacitracin-assisted synthesis of spherical BiVO4 nanoparticles with C doping for remarkable photocatalytic performance under visible light

The spherical BiVO₄ nanoparticles with C doping were fabricated by using bacitracin as a biological template through hydrothermal-calcination method. And the prepared photocatalysts have excellent photocatalytic performance under visible light.

Formation mechanism of porous rose-like WO3 and its photoresponse and stability study

Fabrication of rose-like WO₃ by chemical bath method.

Continuously Improved Photocatalytic Performance of Zn2SnO4/SnO2/Cu2O Composites by Structural Modulation and Band Alignment Modification

Improving the photocatalytic performance of multi-component photocatalysts through structural modulation and band alignment engineering has attracted great interest in the context of solar energy utilization and conversion. In our work, Zn₂SnO₄/SnO₂ hierarchical architectures comprising nanorod building block assemblies were first achieved via a facile solvothermal synthesis route with lysine and ethylenediamine (EDA) as directing agents, and then chemically etched in NaOH solution to enlarge the surface area and augment active sites. The etched Zn₂SnO₄/SnO₂ hierarchical architectures were further decorated by Cu₂O nanoparticles though an in situ chemical deposition method based on band alignment engineering. In comparison with unetched Zn₂SnO₄/SnO₂, the specific surface area of Zn₂SnO₄/SnO₂/Cu₂O hierarchical architectures became larger, and the responsive region and absorbance intensity became wider and higher in the whole visible-light range. Zn₂SnO₄/SnO₂/Cu₂O hybrid photocatalysts presented enormously improved visible-light photocatalytic behaviour for Rhodamine B (RhB) decomposition. The enhancement of photocatalytic behaviour was dominantly attributed to the synergy effect of the larger specific surface area, higher light absorption capacity, and more effective photo-induced charge carrier separation and migration. A proposed mechanism for the enormously promoted photocatalytic behaviour is brought forth on the basis of the energy-band structure combined with experimental results.

Strong Hollow Spherical La2NiO4 Photocatalytic Microreactor for Round-the-Clock Environmental Remediation

This work reports a moderate round-the-clock route to treating organic pollutants by utilizing a La₂NiO₄ hollow-sphere microreactor. A glycerol-assisted solvothermal route followed by an annealing process was applied for fabricating the catalyst. Both the physicochemical properties and the catalytic performance of the as-obtained microreactor for treating pollutants were discussed. The microreactor exhibited a strong ability to degrade phenol and anionic dyes in the absence of light irradiation, owing to its high surface area and positively charged surface. With the aid of visible-light irradiation, the degradation rate of the organic pollutants could be further accelerated due to the light multireflection in a hollow structure, which enhances the utilization of light. The present work indicates that the hollow-sphere La₂NiO₄ microreactor is effectively energy saving for environmental remediation.

Enhancement of Photocatalytic Activity under Visible Light Irradiation via the AgI@TCNQ Core-Shell Structure

In this paper, a AgI@TCNQ photocatalyst with a core-shell structure was reported. A two-dimensional TCNQ (7,7,8,8-Tetracyanoquinodimethane) nanosheet, with a π-π conjugate structure, was used as a shell layer to realize the flexible coating on the surface of AgI nanoparticles. These special core-shell structure composites solve the key problems of the small interface of the bulk composites and the lesser charge transfer paths, which could accelerate the migration of photogenerated carriers. Thus, the AgI@TCNQ photocatalysts showed the better photodegradation performance for the methylene blue (MB) solution, and the degradation rate of AgI@TCNQ (1 wt.%) composite was 1.8 times than AgI under irradiation. The reactive species trapping experiments demonstrated that ·O2-, h+, and ·OH all participated in the MB degradation process. The photocatalytic mechanism of AgI@TCNQ composites could be rationally explained by considering the Z-scheme structure, resulting in a higher redox potential and more efficient separation of charge carriers. At the same time, the unique core-shell structure provides a larger contact area, expands the charge transport channel, and increases the surface active sites, which are beneficial for improving photocatalytic performance.

Novel one-step combustion synthesis of BiOBr:Yb3+,Er3+/AgBr upconversion heterojunction photocatalysts with enhanced vis/NIR photocatalytic activities

A simple combustion method was reported to prepare a novel BiOBr:Yb³⁺,Er³⁺/AgBr (BYE/AgBr) heterojunction photocatalyst.

One-Pot Hydrothermal Synthesis of SnO2/BiOBr Heterojunction Photocatalysts for the Efficient Degradation of Organic Pollutants Under Visible Light

The establishment of p-n heterojunction between semiconductors is an effective means to improve the performance of semiconductor photocatalysts. For the first time, we synthesize SnO₂/BiOBr heterojunction photocatalysts using a one-step hydrothermal method. Systematic material characterizations suggest that the photocatalysts consist of irregular BiOBr nanosheets with the length about 200 nm and width about 150 nm, and SnO₂ nanoparticles are anchored uniformly onto the nanosheets. Most importantly, electrochemical characterizations including transient photocurrent profiles and electrochemical impedance spectra suggest that SnO₂/BiOBr heterojunctions are created, which facilitates the charge separation and transfer efficiency of photogenerated charge carriers. As such, SnO₂/BiOBr photocatalysts exhibit remarkable photocatalytic activities in terms of degrading a series of organic pollutants. Radical trapping experiments and electron spin resonance spectra suggest that superoxide radicals (•O^2-) and hydroxyl radicals (•OH) are primary medium species running through the photocatalytic degradation process and enhanced photocatalytic performance.

Quantum dot-decorated semiconductor micro- and nanoparticles: A review of their synthesis, characterization and application in photocatalysis

Quantum dot (QD)-decorated semiconductor micro- and nanoparticles are a new class of functional nanomaterials that have attracted considerable interest for their unique structural, optical and electronic properties that result from the large surface-to-volume ratio and the quantum confinement effect. In addition, because of QDs' excellent light-harvesting capacity, unique photoinduced electron transfer, and up-conversion behaviour, semiconductor nanoparticles decorated with quantum dots have been used widely in photocatalytic applications for the degradation of organic pollutants in both the gas and aqueous phases. This review is a comprehensive overview of the recent progress in synthesis methods for quantum dots and quantum dot-decorated semiconductor composites with an emphasis on their composition, morphology and optical behaviour. Furthermore, various approaches used for the preparation of QD-based composites are discussed in detail with respect to visible and UV light-induced photoactivity. Finally, an outlook on future development is proposed with the goal of overcoming challenges and stimulating further research into this promising field.

Ag3PO4@UMOFNs Core-Shell Structure: Two-Dimensional MOFs Promoted Photoinduced Charge Separation and Photocatalysis

Metal-organic frameworks (MOFs) are a new type of functional material that is self-assembled by metal ions and organic ligands. In this paper, a bimetal-organic framework was synthesized and stripped into two-dimensional nanosheets structure via an ultrasonic method. We coated the UMOFNs (ultrathinning MOFs into two-dimensional nanosheets) on Ag₃PO₄ nanoparticles to obtain Ag₃PO₄@UMOFNs core-shell photocatalysts. Under visible-light irradiation, the degradation of phenol was 100% within 16 min, and the degradation of biphenyl A was 98.9% within 20 min via Ag₃PO₄@UMOFNs (5 wt %). These values were 1.6- and 1.8-times higher than Ag₃PO₄, respectively. The activity of the Ag₃PO₄@UMOFNs increased due to the synergistic effects. The π-π bonds of the organic ligands and weak interactions between UMOFNs and Ag₃PO₄ collectively promote charge transfer. In addition, matching energy-level structures and a sufficiently large contact area accelerate the separation of the photogenerated charges and improve the activity. This remarkably improves the photocatalytic activity.

Surface Decoration of ZnWO₄ Nanorods with Cu₂O Nanoparticles to Build Heterostructure with Enhanced Photocatalysis

The surface of ZnWO₄ nanorods was decorated with Cu₂O nanoparticles (Cu₂O/ZnWO₄) prepared through a precipitation method. The Cu₂O nanoparticles were tightly deposited on the ZnWO₄ surface and had average diameters of 20 nm. The nanoparticles not only promoted the absorption and utilization of visible light but also facilitated the separation of photogenerated charge carriers. This brought an improvement of the photocatalytic activity. The 5 wt % Cu₂O/ZnWO₄ photocatalyst displayed the highest degrade efficiency for methylene blue (MB) degradation under visible light, which was 7.8 and 2 times higher than pure ZnWO₄ and Cu₂O, respectively. Meanwhile, the Cu₂O/ZnWO₄ composite photocatalyst was able to go through phenol degradation under visible light. The results of photoluminescence (PL), photocurrent, and electrochemical impedance spectra (EIS) measurements were consistent and prove the rapid separation of charge, which originated from the match level structure and the close contact with the interface. The radical and hole trapping experiments were carried out to detect the main active substances in the photodegradation process. The holes and ·O₂⁻ radicals were predicted to dominate the photocatalytic process. Based on the characterization analysis and experiment results, a possible photocatalytic mechanism for enhancing photocatalytic activity was proposed.

Dissimilitude behaviour of Cu2O nano-octahedra and nano-cubes towards photo- and electrocatalytic activities

Nano-octahedra are photocatalytically active for the removal of organic contaminants of water, whereas nanocubes are electrocatalytically active towards oxygen reduction reactions.

Fabrication of magnetically separable NiFe2O4/BiOI nanocomposites with enhanced photocatalytic performance under visible-light irradiation

SEM image of as-synthesized NiFe₂O₄/BiOI (NFO/BOI) nanocomposites (a) and schematic illustration of excitation and separation of photo-induced electron–hole pairs for NFO/BOI nanocomposites (b).

Fabrication of Ag3PO4/GO/NiFe2O4 composites with highly efficient and stable visible-light-driven photocatalytic degradation of rhodamine B

Effective visible-light-driven Ag₃PO₄/GO/NiFe₂O₄Z-scheme magnetic composites were successfully fabricated by a simple ion-exchange deposition method. The Ag₃PO₄/GO/NiFe₂O₄ (8%) composite exhibited excellent photocatalytic activity (degradation efficiency was ∼96% within 15 min and kinetic constant reached 0.1956 min⁻¹) and stability when compared to Ag₃PO₄, NiFe₂O₄, and Ag₃PO₄/NiFe₂O₄ for rhodamine B (RhB) degradation. Furthermore, by electrochemical and fluorescence measurements, the Ag₃PO₄/GO/NiFe₂O₄ (8%) material also showed larger transient photocurrent, lower impedance, and longer fluorescence lifetime (7.82 ns). Comparing the activity result dependence with characterization results, it was indicated that photocatalytic activity depended on fast charge transfer from Ag₃PO₄ to NiFe₂O₄ through GO sheet. The h⁺ and ·O₂⁻ species played important roles in RhB degradation under visible-light. A possible Z-scheme mechanism is proposed over the Ag₃PO₄/GO/NiFe₂O₄ (8%) composite. This study might provide a promising visible light responsive photocatalyst for the photocatalytic degradation of organic dyes in wastewater.

Effective visible-light-driven Ag₃PO₄/GO/NiFe₂O₄Z-scheme magnetic composites were successfully fabricated by a simple ion-exchange deposition method. The composites exhibited excellent photocatalytic activity and stability for RhB degradation.

Preparation of CdS and Bi2S3 quantum dots co-decorated perovskite-type KNbO3 ternary heterostructure with improved visible light photocatalytic activity and stability for phenol degradation

A combination of the hydrothermal route with a linker assisted attachment method was used to obtain efficient CdS/Bi₂S₃ quantum dot-decorated perovskite type KNbO₃.