Strain-Engineering of Mesoporous Cs3Bi2Br9/BiVO4 S-Scheme Heterojunction for Efficient CO2 Photoreduction

Slow charge kinetics and unfavorable CO₂ adsorption/activation strongly inhibit CO₂ photoreduction. In this study, a strain-engineered Cs₃Bi₂Br₉/hierarchically porous BiVO₄ (s-CBB/HP-BVO) heterojunction with improved charge separation and tailored CO₂ adsorption/activation capability is developed. Density functional theory calculations suggest that the presence of tensile strain in Cs₃Bi₂Br₉ can significantly downshift the p-band center of the active Bi atoms, which enhances the adsorption/activation of inert CO₂. Meanwhile, in situ irradiation X-ray photoelectron spectroscopy and electron spin resonance confirm that efficient charge transfer occurs in s-CBB/HP-BVO following an S-scheme with built-in electric field acceleration. Therefore, the well-designed s-CBB/HP-BVO heterojunction exhibits a boosted photocatalytic activity, with a total electron consumption rate of 70.63 µmol g⁻¹ h⁻¹, and 79.66% selectivity of CO production. Additionally, in situ diffuse reflectance infrared Fourier transform spectroscopy reveals that CO₂ photoreduction undergoes a formaldehyde-mediated reaction process. This work provides insight into strain engineering to improve the photocatalytic performance of halide perovskite.     

Promoted Photocharge Separation in 2D Lateral Epitaxial Heterostructure for Visible-Light-Driven CO2 Photoreduction

Photocarrier recombination remains a big barrier for the improvement of solar energy conversion efficiency. For 2D materials, construction of heterostructures represents an efficient strategy to promote photoexcited carrier separation via an internal electric field at the heterointerface. However, due to the difficulty in seeking two components with suitable crystal lattice mismatch, most of the current 2D heterostructures are vertical heterostructures and the exploration of 2D lateral heterostructures is scarce and limited. Here, lateral epitaxial heterostructures of BiOCl @ Bi₂O₃ at the atomic level are fabricated via sonicating-assisted etching of Cl in BiOCl. This unique lateral heterostructure expedites photoexcited charge separation and transportation through the internal electric field induced by chemical bonding at the lateral interface. As a result, the lateral BiOCl @ Bi₂O₃ heterostructure demonstrates superior CO₂ photoreduction properties with a CO yield rate of about 30 µmol g⁻¹ h⁻¹ under visible light illumination. The strategy to fabricate lateral epitaxial heterostructures in this work is expected to provide inspiration for preparing other 2D lateral heterostructures used in optoelectronic devices, energy conversion, and storage fields.     

Atomic Interface Engineering of Single-Atom Pt/TiO2-Ti3C2 for Boosting Photocatalytic CO2 Reduction

Solar-driven CO₂ conversion into valuable fuels is a promising strategy to alleviate the energy and environmental issues. However, inefficient charge separation and transfer greatly limits the photocatalytic CO₂ reduction efficiency. Herein, single-atom Pt anchored on 3D hierarchical TiO₂-Ti₃C₂ with atomic-scale interface engineering is successfully synthesized through an in situ transformation and photoreduction method. The in situ growth of TiO₂ on Ti₃C₂ nanosheets can not only provide interfacial driving force for the charge transport, but also create an atomic-level charge transfer channel for directional electron migration. Moreover, the single-atom Pt anchored on TiO₂ or Ti₃C₂ can effectively capture the photogenerated electrons through the atomic interfacial Pt O bond with shortened charge migration distance, and simultaneously serve as active sites for CO₂ adsorption and activation. Benefiting from the synergistic effect of the atomic interface engineering of single-atom Pt and interfacial Ti O Ti, the optimized photocatalyst exhibits excellent CO₂-to-CO conversion activity of 20.5 µmol g⁻¹ h⁻¹ with a selectivity of 96%, which is five times that of commercial TiO₂ (P25). This work sheds new light on designing ideal atomic-scale interface and single-atom catalysts for efficient solar fuel conversation.     

Salt-Assisted Low-Temperature Growth of 2D Bi2O2Se with Controlled Thickness for Electronics

Bi₂O₂Se is the most promising 2D material due to its semiconducting feature and high mobility, making it propitious channel material for high-performance electronics that demands highly crystalline Bi₂O₂Se at low-growth temperature. Here, a low-temperature salt-assisted chemical vapor deposition approach for growing single-domain Bi₂O₂Se on a millimeter scale with thicknesses of multilayer to monolayer is presented. Because of the advantage of thickness-dependent growth, systematical scrutiny of layer-dependent Raman spectroscopy of Bi₂O₂Se from monolayer to bulk is investigated, revealing a redshift of the A_1g mode at 162.4 cm⁻¹. Moreover, the long-term environmental stability of ≈2.4 nm thick Bi₂O₂Se is confirmed after exposing the sample for 1.5 years to air. The backgated field effect transistor (FET) based on a few-layered Bi₂O₂Se flake represents decent carrier mobility (≈287 cm² V⁻¹s⁻¹) and an ON/OFF ratio of up to 10⁷. This report indicates a technique to grow large-domain thickness controlled Bi₂O₂Se single crystals for electronics.     

Highly efficient nanostructured metal-decorated hybrid semiconductors for solar conversion of CO2 with almost complete CO selectivity

Photocatalytic reduction of CO₂ into solar fuels is regarded as a promising method to address global warming and energy crisis problems. Although heterostructured hybrid metal oxide catalysts have been used for CO₂ reduction, selective control for CO production-only remains the subject of debate. In this paper, we report an absolute selectivity for CO production-only with enhanced photocatalytic ability using Ag-decorated reduced titanium oxide/tungsten hybrid nanoparticles (blue TiO₂/WO₃–Ag HNPs) at 1166.72 μmol g⁻¹ h⁻¹ with an apparent quantum yield of 34.8%. The construction of a Z-scheme between blue TiO₂ and WO₃ domains with an excellent band alignment provided remarkably improved separation of photoinduced charges. Importantly, the presence of novel Ag not only produces the highest selectivity up to 100% CO production-only, but also increases the photocatalytic electron reaction rate (2333.44 μmol g⁻¹ h⁻¹).     

The effects of morphologies on photoreduction of carbon dioxide to gaseous fuel over tin disulfide under visible light irradiation

Artificial photosynthesis has attracted a lot of attention because it can tackle both global environmental problems and energy crisis. In this paper, SnS₂ with different morphologies were synthesized to study their activity and selectivity of photocatalytic reduction of carbon dioxide (CO₂). The size of tablet-like SnS₂ is around 80–120 nm while the flower-like SnS₂ is composed of nanosheets with a thickness of 10 nm. The reduction products of the as-obtained samples are both CO and CH₄. The flower-like SnS₂ sample processes more efficacious separation of photogenerated carriers compared to tablet-like SnS₂ and shows higher photocatalytic reduction efficiency with CH₄ yield of 97.5 μmol g⁻¹, which is approximately 5.7 times higher than that of tablet-like SnS₂, while the tablet-like SnS₂ shows high selectivity (79%) for CO production. The results reveal that the morphology plays an important role in the activity and selectivity of photocatalytic reduction of CO₂ over SnS₂.     

Enhanced Interfacial Charge Transfer/Separation By LSPR-Induced Defective Semiconductor Toward High Co2RR Performance

Solar-driven reduction of CO₂ emissions into high-value-added carbonaceous compounds has been recognized as a sustainable energy conversion way. The high-efficiency charge separation and effective activation are the critical issues in the process. The local plasma effect of metal and the vacancy of semiconductors in the metal-semiconductor heterostructure can solve this issue extensively. Herein, an oxygen vacancy photocatalyst containing uniform Ag nanoparticles (Ag-20@Nb₂O_5-x) is designed, which exhibits an excellent reduction performance and the CO yield can reach 59.13 µmol g⁻¹ with high selectivity. The carrier migration is accelerated and the activation of CO₂ is facilitated by the local surface plasmon effect and oxygen vacancy. Moreover, the photocatalytic CO₂ reduction mechanism is revealed based on the density functional theory and in situ technology in detail. This work provides an in-depth understanding of the design of more ingenious metal-semiconductor photocatalysts to achieve more efficient charge transfer.     

In Situ Constructed Perovskite–Chalcogenide Heterojunction for Photocatalytic CO2 Reduction

Perovskite nanocrystals (PNCs) are promising candidates for solar-to-fuel conversions yet exhibit low photocatalytic activities mainly due to serious recombination of photogenerated charge carriers. Constructing heterojunction is regarded as an effective method to promote the separation of charge carriers in PNCs. However, the low interfacial quality and non-directional charge transfer in heterojunction lead to low charge transfer efficiency. Herein, a CsPbBr₃–CdZnS heterojunction is designed and prepared via an in situ hot-injection method for photocatalytic CO₂ reduction. It is found that the high-quality interface in heterojunction and anisotropic charge transfer of CdZnS nanorods (NRs) enable efficient spatial separation of charge carriers in CsPbBr₃–CdZnS heterojunction. The CsPbBr₃–CdZnS heterojunction achieves a higher CO yield (55.8 µmol g⁻¹ h⁻¹) than that of the pristine CsPbBr₃ NCs (13.9 µmol g⁻¹ h⁻¹). Furthermore, spectroscopic experiments and density functional theory (DFT) simulations further confirm that the suppressed recombination of charge carriers and lowered energy barrier for CO₂ reduction contribute to the improved photocatalytic activity of the CsPbBr₃–CdZnS heterojunction. This work demonstrates a valid method to construct high-quality heterojunction with directional charge transfer for photocatalytic CO₂ reduction. This study is expected to pave a new avenue to design perovskite–chalcogenide heterojunction.     

Synergistic Functionality of Dopants and Defects in Co-Phthalocyanine/B-CN Z-Scheme Photocatalysts for Promoting Photocatalytic CO2 Reduction Reactions

The realization of solar-light-driven CO₂ reduction reactions (CO₂ RR) is essential for the commercial development of renewable energy modules and the reduction of global CO₂ emissions. Combining experimental measurements and theoretical calculations, to introduce boron dopants and nitrogen defects in graphitic carbon nitride (g-C₃N₄), sodium borohydride is simply calcined with the mixture of g-C₃N₄ (CN), followed by the introduction of ultrathin Co phthalocyanine through phosphate groups. By strengthening H-bonding interactions, the resultant CoPc/P-BNDCN nanocomposite showed excellent photocatalytic CO₂ reduction activity, releasing 197.76 and 130.32 µmol h⁻¹ g⁻¹ CO and CH₄, respectively, and conveying an unprecedented 10-26-time improvement under visible-light irradiation. The substantial tuning is performed towards the conduction and valance band locations by B-dopants and N-defects to modulate the band structure for significantly accelerated CO₂ RR. Through the use of ultrathin metal phthalocyanine assemblies that have a lot of single-atom sites, this work demonstrates a sustainable approach for achieving effective photocatalytic CO₂ activation. More importantly, the excellent photoactivity is attributed to the fast charge separation via Z-scheme transfer mechanism formed by the universally facile strategy of dimension-matched ultrathin (≈4 nm) metal phthalocyanine-assisted nanocomposites.     

Fabrication of Bi2WO6/In2O3 photocatalysts with efficient photocatalytic performance for the degradation of organic pollutants: Insight into the role of oxygen vacancy and heterojunction

Photocatalysis is an attractive and green strategy for organic pollutant removal. The development of alternative and effective photocatalysts has attracted great attention. Herein, we rationally engineer an alternative rich-oxygen vacancies (OVs) Bi₂WO₆/In₂O₃ composite photocatalyst via integrating the calcination and hydrothermal method for removing organic dyes (rhodamine B). Thanks to the synergistic effect of OVs and heterojunction structure, the 80 wt% Bi₂WO₆/In₂O₃ (BiIn80) displays enhanced photocatalytic degradation effect. The degradation rate of BiIn80 is up to 97.3% under light irradiation within 120 min and the reaction rate constant k value (0.03221 min⁻¹) is about 15-fold and 4.17-fold as high as those of In₂O₃ (0.00203 min⁻¹) and Bi₂WO₆ (0.00772 min⁻¹), respectively. The heterostructure of Bi₂WO₆/In₂O₃ can extend the lifespan of the photogenerated charge carriers. Moreover, the density functional theory (DFT) calculations reveal that the OVs in Bi₂WO₆/In₂O₃ can boost visible light absorbability by decreasing band gap value and serve as the extra electron transfer channels to enhance the separation efficiency of photogenerated electron-hole pairs. This study not only provides an alternative route for fabricating highly efficient heterojunction photocatalysts, but also obtains better understanding of the synergistic effect of OVs and heterojunction on enhancing the photocatalytic performance.     

Highly Selective Photoreduction of CO2 with Suppressing H2 Evolution by Plasmonic Au/CdSe–Cu2O Hierarchical Nanostructures under Visible Light

Here, the photocatalytic CO₂ reduction reaction (CO₂RR) with the selectivity of carbon products up to 100% is realized by completely suppressing the H₂ evolution reaction under visible light (λ > 420 nm) irradiation. To target this, plasmonic Au/CdSe dumbbell nanorods enhance light harvesting and produce a plasmon‐enhanced charge‐rich environment; peripheral Cu₂O provides rich active sites for CO₂ reduction and suppresses the hydrogen generation to improve the selectivity of carbon products. The middle CdSe serves as a bridge to transfer the photocharges. Based on synthesizing these Au/CdSe–Cu₂O hierarchical nanostructures (HNSs), efficient photoinduced electron/hole (e^?/h⁺) separation and 100% of CO selectivity can be realized. Also, the 2e^?/2H⁺ products of CO can be further enhanced and hydrogenated to effectively complete 8e^?/8H⁺ reduction of CO₂ to methane (CH₄), where a sufficient CO concentration and the proton provided by H₂O reduction are indispensable. Under the optimum condition, the Au/CdSe–Cu₂O HNSs display high photocatalytic activity and stability, where the stable gas generation rates are 254 and 123 µmol g^?1 h^?1 for CO and CH₄ over a 60 h period.     

Ferroelectric and pyroelectric properties of (Na0.5Bi0.5)TiO3-BaTiO3 based trilayered thin films

Trilayered Bi_3.25La_0.75Ti₃O₁₂ (25 nm)/(Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃ (300 nm)/Bi_3.25La_0.75Ti₃O₁₂ (25 nm) and Pb(Zr_0.4Ti_0.6)O₃ (25 nm)/(Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃ (300 nm)/Pb(Zr_0.4Ti_0.6)O₃ (25 nm) thin films without undesirable phases have been deposited on Pt/Ti/SiO₂/Si substrates. It was found that the Bi_3.25La_0.75Ti₃O₁₂ and Pb(Zr_0.4Ti_0.6)O₃ layers are very effective to inhibit the charge transport in the trilayered films. Much better insulating properties than those of (Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃ films have been achieved in the trilayered films. The trilayered films show good dielectric, ferroelectric and pyroelectric properties. Remnant polarizations 2P_r of 16 µC/cm² and 34 µC/cm², pyroelectric coefficients of 4.8 × 10^− 4 C m^− 2 K^− 1 and 7.0 × 10^− 4 C m^− 2 K^− 1 have been obtained for the Bi_3.25La_0.75Ti₃O₁₂/(Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃/Bi_3.25La_0.75Ti₃O₁₂ and Pb(Zr_0.4Ti_0.6)O₃/(Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃/Pb(Zr_0.4Ti_0.6)O₃ thin films, respectively. The trilayered films are promising candidates for sensor and actuator applications.     

Spatial Specific Janus S-Scheme Photocatalyst with Enhanced H2O2 Production Performance

Photocatalytic oxygen reduction reaction (ORR) for H₂O₂ production in the absence of sacrificing agents is a green approach and of great significance, where the design of photocatalysts with high performance is the central task. Herein, a spatial specific S-scheme heterojunction design by introducing a novel semiconducting pair with a S-scheme mechanism in a purpose-designed Janus core–shell-structured hollow morphology is reported. In this design, TiO₂ nanocrystals are grown inside the inner wall of resorcinol-formaldehyde (RF) resin hollow nanocakes with a reverse bumpy ball morphology (TiO₂@RF). The S-scheme heterojunction preserves the high redox ability of the TiO₂ and RF pair, the spatial specific Janus design enhances the charge separation, promotes active site exposure, and reduces the H₂O₂ decomposition to a large extent. The TiO₂@RF photocatalyst shows a high H₂O₂ yield of 66.6 mM g⁻¹ h⁻¹ and solar-to-chemical conversion efficiency of 1.11%, superior to another Janus structure (RF@TiO₂) with the same heterojunction but a reversed Janus spatial arrangement, and most reported photocatalysts under similar reaction conditions. The work has paved the way toward the design of next-generation photocatalysts for green synthesis of H₂O₂ production.     

Graphitic-C3N4/ZnCr-layered double hydroxide 2D/2D nanosheet heterojunction: Mesoporous photocatalyst for advanced oxidation of azo dyes with in situ produced H2O2

In this study the constructional modification of Graphitic carbon nitride nanosheet (GCN-ns) has been made with the aid of ZnCr layered double hydroxide (ZC-LDH) in a unique 2D-2D structure to enhance its visible light absorption. Optical and morphological study presents successful incorporation of ZC-LDH on the surface of GCN-ns. Through adjusting of GCN-ns by ZC-LDH lower recombination rate of e^?/h⁺ pairs, longer lifetimes and an increase in contamination reduction was brought out. The binary nanocomposite was employed to effectively degrade Rhodamine B under UV/vis light irradiation. The improvement in photocatalytic abilities was proven to be related to in situ self-production of H₂O₂ on GCN-ns/ZC-LDH surface by Xe light irradiation which in return accounts for additional hydroxide radical generation. Radical quenching experiments specified the main active species involved while the consequent step-scheme (S-scheme) charge transfer mechanism was proposed.     

Synthesis of efficient composite photocatalysts from solid solution Bi3O4Cl0.5Br0.5 and Ag-AgI/AgCl for decomposition the oil field pollutants of phenol and acrylamide

Composite photocatalysts typically display enhanced photocatalytic performance. In this paper, the polycomplex Ag-AgI/AgCl/Bi₃O₄Cl_0.5Br_0.5 was prepared by a photo-reduction approach. The identity of the composite was confirmed by several characterization methods including, the structure of sample was confirmed by X-ray diffraction and high-resolution transmission electron microscopy, the morphology and element information of sample was investigated through scanning electron microscopy and SEM-mapping, the surface valence states of sample was confirmed by the X-ray photoelectron spectroscopy. Oilfield produced wastewater was chosen as the target in this study due to the toxicity and persistent nature of its components (pollutants such as, phenol and acrylamide). Ag-AgI/AgCl/Bi₃O₄Cl_0.5Br_0.5 exhibited superior photocatalytic activity than either Bi₃O₄Cl_0.5Br_0.5 or Ag-AgI/AgCl, after irradiation with visible and UV light for 5 h. Under visible irradiation 5 h, the Ag-AgI/AgCl/Bi₃O₄Cl_0.5Br_0.5 exhibited excellent photocatalytic activity for degradation phenol of 57.7%, which was about 4 times and 1.5 times higher than Bi₃O₄Cl_0.5Br_0.5 and Ag-AgI/AgCl, respectively. Additionally, the Ag-AgI/AgCl/Bi₃O₄Cl_0.5Br_0.5 displayed photodegradation rates of 41.0% for acrylamide after 5 h UV–visible light irradiation, which was approximately 3.1 times and 1.6 times when treated with Bi₃O₄Cl_0.5Br_0.5 and Ag-AgI/AgCl, respectively. The remarkable photocatalytic activity of AgI/AgCl/Bi₃O₄Cl_0.5Br_0.5 was further confirmed by the PL spectra, photocurrent response and electrochemical impedance. Furthermore, the stability and reusability were investigated by recycling experiments. In combination with the trapping experiments, the surface Plasmon resonance (SPR) of Ag-AgI/AgCl/Bi₃O₄Cl_0.5Br_0.5 reveals the catalyst has an ultra-fast charge-separation efficiency and possesses a high redox ability. In this this paper, a new approach for the synthesis of quaternary composites is described and these photocatalysts have been shown to efficiently degrade of oil field pollutants.     

Facile preparation of heterostructured Bi2O3/Bi2MoO6 hollow microspheres with enhanced visible-light-driven photocatalytic and antimicrobial activity

Hierarchical β-Bi₂O₃/Bi₂MoO₆ heterostructured flower-like microspheres assembled from nanoplates with different β-Bi₂O₃ loadings (0–26.5 mol%) were synthesized through a one-step template-free solvothermal route. Under visible-light illumination (λ > 420 nm), over 99% of rhodamine B was degraded within 90 min on the 21.9 mol% of β-Bi₂O₃ loading Bi₂O₃/Bi₂MoO₆ microspheres. The remarkable enhancement of photocatalytic activity of the hierarchical Bi₂O₃/Bi₂MoO₆ micro/nanostructures can be attributed to the effective separation of the photoinduced charge carriers at the interfaces and in the semiconductors. The electrons (e⁻) are the main active species in aqueous solution under visible-light irradiation. The Bi₂O₃/Bi₂MoO₆ also displays visible-light photocatalytic activity for the destruction of E. coli. In addition, the β-Bi₂O₃ in the hierarchical Bi₂O₃/Bi₂MoO₆ microspheres is very stable and the composite can be easily recycled by a simple filtration step, thus the second pollution can be effectively avoided. A possible photocatalytic mechanism was proposed based on the experimental results.     

Heterostructured Fe3O4/Bi2O2CO3 photocatalyst: Synthesis,characterization and application in recyclable photodegradation of organic dyes under visible light irradiation

Heterostructured Fe₃O₄/Bi₂O₂CO₃ photocatalyst was synthesized by a two-step method. First, Fe₃O₄ nanoparticles with the size of ca. 10 nm were synthesized by chemical method at room temperature and then heterostructured Fe₃O₄/Bi₂O₂CO₃ photocatalyst was synthesized by hydrothermal method at 180 °C for 24 h with the addition of 10 wt% Fe₃O₄ nanoparticles into the precursor suspension of Bi₂O₂CO₃. The pH value of synthesis suspension was adjusted to 4 and 6 with the addition of 2 M NaOH aqueous solution. By controlling the pH of synthesis suspension at 4 and 6, sphere- and flower-like Fe₃O₄/Bi₂O₂CO₃ photocatalysts were obtained, respectively. Both photocatalysts demonstrate superparamagnetic behavior at room temperature. The UV–vis diffuse reflectance spectra of the photocatalysts confirm that all the heterostructured photocatalysts are responsive to visible light. The photocatalytic activity of the heterostructured photocatalysts was evaluated for the degradation of methylene blue (MB) and methyl orange (MO) in aqueous solution over the photocatalysts under visible light irradiation. The heterostructured photocatalysts prepared in this study exhibit highly efficient visible-light-driven photocatalytic activity for the degradation of MB and MO, and they can be easily recovered by applying an external magnetic field.     

Mg0.5NixZn0.5-xFe2O4 spinel as a sustainable magnetic nano-photocatalyst with dopant driven band shifting and reduced recombination for visible and solar degradation of Reactive Blue-19

Focussing on visible light active ferrites for high performance removal of noxious pollutants, we report the synthesis of Mg_0.5Ni_xZn_0.5-xFe₂O₄ (x = 0.1, 0.2, 0.3, 0.4, & 0.5) ferrite nanoparticle for degradation of reactive blue-19 (RB-19). Lattice parameters calculated using intense X-ray diffraction (XRD) peaks and Nelson-Riley plots (N-R plot) are in well agreement with each other. The sample Mg_0.5Ni_0.4Zn_0.1Fe₂O₄ (M5N4) exhibits best performance with 99.5% RB-19 degradation in 90 min under visible light. Photoluminescence (PL) results confirm that recombination of charge carriers is highly reduced in the photocatalyst. Scavenging experiments suggest that O₂⁻ radicals were the dominant species responsible for photocatalytic performance. The photocatalytic mechanism was explained in terms of dopant driven shifting of conduction bands and valence bands (calculated by Mott-Schottky plots). The thermodynamic probability of radical generation along with role of redox cycles of metal ions has been discussed in the mechanism. The dye degradation was ascertained by detection of intermediates via mass spectrometry analysis and a possible degradation route was also predicted. The findings in this work provide intriguing opportunities to modify the electronic band structure of spinel ferrites for visible and solar light photocatalytic activity for environmental detoxification.     

Atomically Dispersed Electron Traps in Cu Doped BiOBr Boosting CO2 Reduction to Methanol by Pure H2O

Overall photocatalytic conversion of CO₂ and pure H₂O driven by solar irradiation into methanol provides a sustainable approach for extraterrestrial synthesis. However, few photocatalysts exhibit efficient production of CH₃OH. Here, BiOBr nanosheets supporting atomic Cu catalysts for CO₂ reduction are reported. The investigation of charge dynamics demonstrates a strong built-in electric field established by isolated Cu sites as electron traps to facilitate charge transfer and stabilize charge carriers. As result, the catalysts exhibit a substantially high catalytic performance with methanol productivity of 627.66 µmol g_catal⁻¹ h⁻¹ and selectivity of ≈90% with an apparent quantum efficiency of 12.23%. Mechanism studies reveal that the high selectivity of methanol can be ascribed to energy-favorable hydrogenation of *CO intermediate giving rise to *CHO. The unfavorable adsorption on Cu₁@BiOBr prevents methanol from being oxidized by photogenerated holes. This work highlights the great potential of single-atom photocatalysts in chemical transformation and energy storage reactions.     

Preparation of Z-scheme Au-Ag2S/Bi2O3 composite by selective deposition method and its improved photocatalytic degradation and reduction activity

In this work, Z-scheme Ag₂S/Bi₂O₃ composites were fabricated through the precipitation of Ag₂S nanoplates on the surface of Bi₂O₃ microrods. Consequently, Au nanoparticles were selectively deposited on the Ag₂S nanoplates surface to obtain.Au-Ag₂S/Bi₂O₃ composites using near-infrared light photodeposition method. The characterization results indicate that the Ag₂S nanoplates were uniformly anchored on Bi₂O₃ surface, and Au nanoparticles were highly dispersed on the surface of Ag₂S nanoplate instead of Bi₂O₃. Acid orange 7 (AO7), Rhodamine B (RhB) and Cr(VI) were chosen as model reactant for the evaluation of photocatalytic degradation and reduction activity of the products under simulated sunlight irradiation. After the decoration of Ag₂S nanoplates, the photocatalytic activity of Ag₂S/Bi₂O₃ is much higher than that of bare Bi₂O₃, and the optimal catalytic efficiency is achieved by 12 %Ag₂S/Bi₂O₃ sample. More importantly, the photocatalytic activity of 12 %Ag₂S/Bi₂O₃ sample can be further enhanced by the selective decoration Au nanoparticles on the Ag₂S nanoplates. Among the ternary composites, 2Au-12 %Ag₂S/Bi₂O₃ sample with the Au content of 2% exhibits highest catalytic efficiency for 60 min (AO7: 96%; RhB: 56%; Cr(VI): 65%). The possible mechanism for the improvement of the photocatalytic activity of Bi₂O₃ by Ag₂S and Au decoration was proposed.