Efficient Photocatalytic CO2 Reduction Research Articles

New insight into efficient photocatalytic CO2 reduction without any sacrifice agent over the novel hierarchical structured SiOC whisker aerogel

Photoreduction of CO2 to valuable fuels provides a promising strategy for managing the global carbon balance using renewable solar energy, yet the design of active, cost-effective, highly selective, and stable CO2 reduction photocatalysts remains a big challenge. Herein, we report a novel SiOC aerogel photocatalyst synthesized by a simple one-step sol-gel process, combined with the supercritical drying technique and heat treatment processes. The resulting SiOC aerogel exhibits a large BET specific area with typical hierarchical structures, which is responsible for the enhanced photocatalytic activity. In addition, the formation mechanism of the SiOC whisker aerogel is revealed in this study. The optimized SiOC aerogel exhibits CH4 and CO evolution activity of 5.8 and 20.5 μmol/g under simulated sunlight irradiation, respectively, without any additional co-catalyst or sacrificial agent, which is 6.4 and 3.9 times higher than those of the pristine SiC aerogel. The density functional theory (DFT) calculation confirms that the resulting SiOC aerogel can effectively adsorb and activate CO2 and H2O molecules on the catalyst surface. The Gibbs free energy diagram further verifies the superior performance of the resulting SiOC aerogel over the pristine SiC and SiO2 cluster via the rate-determining step calculations. The high efficiency of CO2 reduction can be attributed to the structural merits and the electronic structures modulation, which greatly achieves fast separation and transfer of charge carriers. The work paves an insight into the rational design of photocatalysts toward simultaneously facilitating carrier separation and CO2 activation from aerogel-based porous materials.

Constructing bridging oxygen vacancies in SnTa2O6−x for efficient and stable photocatalytic CO2 reduction under visible light irradiation

Construction of oxygen vacancies is a common strategy to improve the performance of metal oxide photocatalysts. However, the oxygen vacancies can be easily filled and consumed by the oxygen atoms of CO2 molecules during CO2 photoreduction reactions, resulting in deactivation of the catalyst. In this study, bridging oxygen vacancies were introduced into SnTa2O6 nanosheets, which remarkably enhanced the photocatalytic performance with good stability. The SnTa2O6−x obtained after 40 s of flame reduction treatment showed 7.5 times higher visible-light-activity than pristine SnTa2O6 (21.1 μmol h−1 g−1 of CO), and sustained good stability even after five cycles. Accompanied by a positive shift in the d-band center, the adsorption configuration of CO2 on the catalysts changed from monodentate to bidentate after the introduction of bridging oxygen vacancies into SnTa2O6, which is beneficial for CO2 adsorption and activation. Furthermore, the bridging oxygen vacancies in SnTa2O6−x can reduce the Gibbs free energy of COOH*, and facilitate the photo conversion of CO2 by receiving photogenerated electrons. The good stability of SnTa2O6−x can be attributed to the distinct molecular configuration of CO2, which avoids filling and consuming the oxygen vacancies.

Construction of ZnIn2S4-CdIn2S4 Microspheres for Efficient Photo-catalytic Reduction of CO2 with Visible Light

ZnIn2S4 has emerged in water splitting and degradation of dyes due to its good stability and light absorption properties. However, there are still few reports of CO2 photoreduction. Herein, we successfully synthesized ZnIn2S4 and obtained a series of ZnIn2S4-CdIn2S4 heterostructured microspheres through the ion exchange method, and first used them in photocatalytic CO2 reduction in noble-metal-free systems. The activity results showed that these ZnIn2S4-CdIn2S4 photocatalysts exhibit excellent catalytic activity under visible light, and the best CO yield is as high as 33.57 μmol·h-1 with a selectivity of 91%. Furthermore, the stability and reusability of ZnIn2S4-CdIn2S4 was firmly confirmed by diverse characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX) and N2 adsorption measurements.

Loading metal nanoparticles on the CoAl-LDH/CGCNN S-scheme heterojunction for efficient photocatalytic CO2 reduction under visible light

Converting CO2 into high-value products by photocatalysis can alleviate the global greenhouse effect and energy crisis. In this work, CoAl-LDH/CGCNN-Metal NPs (AC-M) ternary photocatalysts were synthesized by calcination, hydrothermal, and ultrasonic self-assembly methods. In pure water, the best sample AC-Au could convert CO2 into CO, CH4, C2H4, and C2H6 with the yields of 5.93, 17.68, 1.25 and 2.15 µmol g−1h−1, respectively, and exhibited good stability within 5 cycles (30 h). The synergistic effect between S-scheme heterojunction and metal NPs could broaden the composite's photo-response range and promote the separation of photogenerated carriers. Furthermore, the metal NPs could also serve as the electron-rich centers to improve the chemisorption of CO2 and convert it into C1 and C2 products under visible light. This work can provide meaningful guidance for studying the efficient reduction of CO2 to C1 and C2 products by S-scheme heterojunction/metal NPs ternary photocatalytic system.

Activated g-C3N4 Photocatalyst with Defect Engineering for Efficient Reduction of CO2 in Water

The conversion and utilization of CO2 into hydrocarbon fuel using solar energy is an attractive way to reduce CO2 emissions. In the photocatalytic CO2 conversion process, a synergistic enhancement of both photoreaction and chemical reaction is quite important for promoting the conversion. Here, we present a facile method for preparing a defective and activated graphitic carbon nitride (g-C3N4) photocatalyst, which exhibits a superior CO2-to-CO production of 32.06 μmol g–1 without sacrificial agent or noble metal. This is about 9.1 times higher than that of the defect containing g-C3N4 (3.51 μmol g–1). The activated g-C3N4, in which the TiO2 species coexist, not only improved the CO production to 54.03 umol g–1 but also reduced CO2 into CH4 with 2.50 umol g–1 in 5 h. This is because the coexistence of TiO2 species in activated g-C3N4 promotes molecule and electron transfer, as observed through experimental characterization techniques. Therefore, this work provides a novel insight into the synthesis of multifunctional g-C3N4 for efficient photocatalytic CO2 reduction with H2O.

Understanding the mechanism of saturated and mono-/tri-lacunary Keggin SiWx doped in Bi2WO6 and BiOBr for efficient photocatalytic CO2 reduction

Different from the doping of common simple ions, polyoxometalates (POMs) with the ability to regulate electron transfer as a large dopant and their doping mechanism is rarely studied. In this work, saturated and mono-/tri-lacunary Keggin SiWx (x = 9, 11, 12) have been successfully doped in Bi2WO6 and BiOBr through a two-step hydrothermal method, respectively, in which SiWx respectively replaced WO42− of Bi2WO6 and Br− of BiOBr, and are denoted as SiWx-Bi2WO6 and SiWx-BiOBr. As a shallow electron trap, SiWx inhibits photoinduced carrier recombination of Bi2WO6 and BiOBr. Besides, SiWx-Bi2WO6 and SiWx-BiOBr behave differently in photocatalytic CO2 reduction, which the CO yields of SiW9-Bi2WO6, SiW11-Bi2WO6 and SiW12-Bi2WO6 are 1.5, 3.3 and 6.2 times higher than Bi2WO6, while the CO yields of SiW9-BiOBr, SiW11-BiOBr and SiW12-BiOBr are 1.6, 2 and 2.6 times that of BiOBr. The corresponding reasons for the different performances can be attributed to the different hydrophobicity of the materials, reduction of the Bi2WO6 and BiOBr nanosheet stacking thickness and inhibition of carrier recombination. The deep insights into the influences of saturated and lacunary POMs on photocatalytic performances provide more ideas for the rational design of photocatalytic materials for CO2 reduction to high-valuable products.

Liquid phase exfoliation of metal–organic frameworks in aqueous quaternary ammonium hydroxide solution enables highly efficient photocatalytic CO2 reduction

Metal−organic framework nanosheets (MONs) show promising applications in many fields, but the production of large amounts of high-quality MONs remains a challenge. Here, we report a general liquid-phase stripped approach to exfoliate a benzoic acid linked MOF (Al2(OH)2TCPP-Co) in water by using quaternary ammonium hydroxides as deprotonation reagent, intercalator and stabilizer simultaneously. It is shown that the stripped yield is high up to 27.5%, the thickness of MONs is mainly 1–3 nm, and the horizontalsize is less than one hundred nanometers. The molecular geometry and alkalinity of quaternary ammonium hydroxides play vital roles in the exfoliation of MONs. Moreover, the MONs have been applied as photocatalysts for the conversion of CO2 to CO in a gas–solid model under UV–visible light illumination without using anyphotosensitizer and sacrificialagents. The productivity rate of CO is 118.7 μmol g−1 h−1, which outperforms most of the photocatalysts reported previously. Thus, the liquid phase stripping method reported in this work has great potential in the large-scale production of MONs for efficient photocatalysis of CO2 reduction in the gaseous phase.

Solar-wind energy complementary coupling realizes magnetic-field assisted efficient photocatalytic CO2 reduction

We report the synthesis of a Z-scheme monolithic photocatalyst in the form of copper foam (CF) supported TiO2 combining Cu2O and Ag nanoparticles (CF@TiO2/Cu2O-Ag). The designed catalysts with efficient charge separation show superior photocatalytic activity toward CO2 reduction, with a maximum CO yielding rate of 25.58 μmol‧g-1‧h-1. More importantly, we develop a solar-wind energy complementary device, which enables the strong coupling of the magnetic field into the photocatalytic reaction. Specifically, the in-situ space electric field generated from the wind-driven induced electromotive force further enhances the separation and transportation of photogenerated charge carriers in the Z-scheme system. The productivity of CO in the proof-of-concept device based on the use of CF@TiO2/Cu2O-Ag catalyst reaches 71.66 μmol‧g-1‧h-1. This study provides an ideal approach for reinforcing photocatalytic CO2 reduction through muti-field coupling and highlights the prospect of solar-wind energy coupled photocatalysis.

Two-dimensional interface engineering of g-C3N4/g-C3N4 nanohybrid: Synergy between isotype and p-n heterojunctions for highly efficient photocatalytic CO2 reduction

The creation of an isotype phase junction has been recognized as an effective means of improving the spatial charge separation and migration in g-C3N4 materials. Nevertheless, due to a lack of electrostatic control in the internal electric field, isotype heterojunction alone is incapable of providing a sufficient driving force to maximize charge carrier transfer. Herein, we present an interface engineering strategy for co-integrating isotype and p-n heterojunctions to fabricate g-C3N4/g-C3N4 nanohybrids using a facile ultrasonic-assisted self-assembly method. The coherent boundary between the two distinct phases of g-C3N4 demonstrates that an intimate 2D interfacial contact can be easily established by π-π stacking interactions because of their high structural similarities and low lattice strain. Furthermore, their compatible and well-matched electronic band structures led to a staggered type II alignment in the lateral heterojunction, which confers the resulting composite with strong redox ability, efficient exciton dissociation, and desirable optoelectronic characteristics beyond those of the two constituents. Essentially, the isotype and p-n heterojunctions work in tandem to create a robust built-in electric field, allowing for effective interfacial charge steering for directional electron migration from BCN to CNx. Benefiting from these merits, the BCN/CNx nanohybrid manifested remarkable CH4 generation from photocatalytic CO2 reduction, outperforming its CNx and BCN counterparts by 1.91 and 6.88-fold, respectively. The midgap states induced by nitrogen defects in CNx also pose a positive effect on the improved photoactivity of the binary composite by acting as an electron reservoir to mediate electron transfer and further impede charge carrier recombination. This proof-of-concept study highlights the significance of interface engineering in charge flow manipulation and utilization for photocatalytic enhancement.

Superheterojunction covalent organic frameworks: Supramolecular synergetic charge transfer for highly efficient photocatalytic CO2 reduction

Photocatalytic conversion of CO2 into value–added chemicals under visible light irradiation is very appealing but challenging due to the easy recombination of hole–electron pairs in traditional photocatalysts. π–π stacking interactions can be favorable for efficient separation and transfer of photo–irradiated charges to promote photocatalysis, but are rarely studied in crystalline porous frameworks like covalent organic frameworks (COFs). Herein, we report a series of thienothiophenes–porphyrin based 2D COFs, denoted as TT–Por(M)–COF (M = 2 H/Co/Cu/Ni), which show enhanced intralayer and interlayer charge separation and migration due to the donor-acceptor heterojunctions and π–stacked columns. The TT–Por(Co)–COF achieves enhanced CO evolution rate than COF–366–Co without the heterojunctions and π–columns (10.05 mmol g–1 h–1 versus 7.10 mmol g–1 h–1) under visible light irradiation. This work not only shows the important role of π–π stacking interactions of COFs for CO2 conversion, but also provides insight into the mechanistic aspect for photocatalysis.

Nanoarchitecture engineering of crumpled polymeric carbon nitride nanosheets for efficient visible-light photocatalytic CO2 reduction

Polymeric carbon nitride nanosheets with few layers have emerged as a new category of semiconductor materials which are promising for photocatalytic applications because of their unique optical and electronic characteristics. The texture and optical–electronic properties of the nanosheets significantly influence the photocatalytic activities. In this study, a series of crumpled polymeric carbon nitride nanosheets was prepared via a facile stepwise pyrolytic strategy and a time-dependent pyrolysis process. The as-obtained nanosheets exhibit a sequential change in morphology from a continuous-aggregation architecture to discrete nanosheets with prolonged thermal-treatment time. The nanosheets with the continuous-aggregation architecture, consisting of small curved nanosheet subunits are laterally large; thus, they can provide numerous reactive sites for surface reactions and awaken intrinsic n → π* electron transitions to promote photocatalytic activity. The optimum crumpled polymeric carbon nitride nanosheet is formed after 2 h of thermal condensation, and it demonstrates efficient CO2-conversion performance with the highest CO-evolution rate of 1287 µmol g−1h−1, which is 7 times more than that of pristine polymeric carbon-nitride nanosheets. This work provides an opportunity to significantly understand the roles of texture and optical–electronic properties in improving the photocatalytic activities of polymeric carbon-nitride nanosheets.

W18O49/MnWO4 heterojunction for highly efficient photocatalytic reduction of CO2 under full spectrum light

Solar-energy-driven CO2 reduction for chemical reagents production, such as CH3OH, CH4 and CO, has tremendous potential for carbon neutrality in the energy industries. However, the low reduction efficiency limits its applicability. Herein, W18O49/MnWO4 (WMn) heterojunctions were prepared via one-step in-situ solvothermal process. Through this method, W18O49 tightly combined with the surface of MnWO4 nanofibers to form nanoflower heterojunction. It was found that under full spectrum light irradiation for 4 h, the yields of photoreduction of CO2 to CO, CH4 and CH3OH by 3–1 WMn heterojunction were 61.74, 71.30 and 18.98 μmol/g, respectively, which were 2.4, 1.8 and 1.1 times that of pristine W18O49, and ca.20 times that of pristine MnWO4 towards CO production. Furthermore, even in the air atmosphere, the WMn heterojunction still performed excellent photocatalytic performance. Systematic investigations demonstrated that the catalytic performance of WMn heterojunction was improved by superior light utilization and more efficient photo-generated carrier separation and migration as compared with W18O49 and MnWO4. Meanwhile, the intermediate products of the photocatalytic CO2 reduction process were also studied in detail by in-situ FTIR. Therefore, this study provides a new way for designing high efficiency of heterojunction for CO2 reduction.

Self-supported CsPbBr3/Ti3C2Tx MXene aerogels towards efficient photocatalytic CO2 reduction

Aerogels, especially MXene aerogels, are an ideal multifunctional platform for developing efficient photocatalysts for CO2 reduction because they are featured by abundant catalytic sites, high electrical conductivity, high gas absorption ability and self-supported structure. However, the pristine MXene aerogel has almost no ability to utilize light, which requires additional photosensitizers to assist it in achieving efficient light harvesting. Herein, we immobilized colloidal CsPbBr3 nanocrystals (NCs) onto the self-supported Ti3C2Tx (where Tx represents surface terminations such as fluorine, oxygen, and hydroxyl groups) MXene aerogels for photocatalytic CO2 reduction. The resultant CsPbBr3/Ti3C2Tx MXene aerogels exhibit a remarkable photocatalytic activity toward CO2 reduction with total electron consumption rate of 112.6 μmol g-1h-1, which is 6.6-fold higher than that of the pristine CsPbBr3 NC powders. The improvement of the photocatalytic performance is presumably attributed to the strong light absorption, effective charge separation and CO2 adsorption in the CsPbBr3/Ti3C2Tx MXene aerogels. This work presents an effective perovskite-based photocatalyst in aerogel form and opens a new avenue for their solar-to-fuel conversions.

In-situ electrochemical-ion-exchange synthesis of S-scheme 1D/2D BiPO4/BiOBr heterojunction film from Bi plate with highly efficient photocatalytic CO2 reduction activity

In-situ electrochemical-ion-exchange synthesis of S-scheme 1D/2D BiPO4/BiOBr heterojunction film from Bi plate with highly efficient photocatalytic CO2 reduction activity

2D/2D Carbon Nitride/Zn-Doped Bismuth Vanadium Oxide S-Scheme Heterojunction for Enhancing Photocatalytic CO2 Reduction into Methanol

Developing superior photocatalytic CO2 conversion systems for the generation of high-valued fuels or chemicals is highly desirable but is still challenging work. Herein, the well-organized carbon nitride/Zn-doped bismuth vanadium oxide (CN-ZnBVO) nanohybrids were constructed by a facile CTAB-assisted solvothermal strategy to achieve an efficient photocatalytic reduction of CO2 to CH3OH under UV–vis light. Impressively, the distinctive butterfly-like 2D/2D CN-ZnBVO catalyst showed markedly enhanced photocatalytic performance in alkaline medium, with the largest CH3OH generation rate of 609.1 μmol g–1 h–1 and a high selectivity of 90.5%, outperforming most recently reported CO2 photoreduction systems. Moreover, the yield of CH3OH remained nearly constant over three successive repeated cycles, signifying its good stability. Detailed characterization and theoretical calculations revealed that the outstanding photocatalytic activity owes much to the more accessible reaction sites and improved CO2 absorption capacity induced by the distinctive micromorphology effect, as well as the localized charge density distribution and fast spatial charge separation and transfer caused by the 2D/2D S-scheme heterojunction, thus providing more photogenerated electrons for efficient CH3OH formation. The present work offers a new perspective for the in situ construction of highly active S-scheme heterostructures for selective photocatalytic CO2 reduction.

A novel metal-free porous covalent organic polymer for efficient room-temperature photocatalytic CO2 reduction via dry-reforming of methane

At room temperature, the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane (DRM) is quite promising and challenging. Herein, we developed a novel covalent organic porous polymer (TPE-COP) with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature, which can efficiently generate syngas (CO and H2). Both electron donor (tris(4-aminophenyl)amine, TAPA) and acceptor (4,4′,4″,4‴-((1 E,1′E,1″E, 1‴E)-(ethene-1,1,2,2-tetrayltetrakis (benzene-4,1-diyl))tetrakis (ethene-2,1-diyl))tetrakis (1-(4-formylbenzyl)quinolin-1-ium), TPE-CHO) were existed in TPE-COP, in which the push–pull effect between them promoted the separation of photogenerated electron–hole, thus greatly improving the photocatalytic activity. Density functional theory (DFT) simulation results show that TPE-COP can form charge-separating species under light irradiation, leading to electrons accumulation in TPE-CHO unit and holes in TAPA, and thus efficiently initiating DRM. After 20 h illumination, the photocatalytic results show that the yields reach 1123.6 and 30.8 μmol g−1 for CO and H2, respectively, which are significantly higher than those of TPE-CHO small molecules. This excellent result is mainly due to the increase of specific surface area, the enhancement of light absorption capacity, and the improvement of photoelectron-generating efficiency after the formation of COP. Overall, this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.

Surfactant-free synthesis of ordered 1D/2D NiZn-LDH heterostructure through oriented attachment for efficient photocatalytic CO2 reduction with nearly 100% CO selectivity

Ordered assembly of anisotropic one-dimensional (1D) and 2D nanomaterials is necessary for preparing delicate heterostructures with close contact to alleviate the energy and environmental crisis. Here, we exploited oriented attachment, a non-classical growth mechanism, as a tool for preparing ordered 1D/2D NiZn layered double hydroxide (Ni-Zn LDH) heterostructures beyond the use of surfactants. Lattice matching between the (101) plane of 1D nanoneedles (NNs) and the (100) plane of 2D nanosheets (NSs) drives the spontaneous ordered assembly of 1D NiZn-LDH NNs on 2D NiZn-LDH NSs. Accordingly, the oxygen-deficient 1D NiZn-LDH capable of CO2 adsorption is, therefore, well dispersed on the 2D platform. The oriented assembly generates strong and intimate interactions between the 1D and 2D units, enabling the efficient transfer of photogenerated electrons from 2D to 1D NiZn-LDH. The oriented 1D/2D NiZn-LDH heterostructure demonstrates superior CO2 photoreduction performance under visible light irradiation, with a CO yield rate of 16,950 µmol g−1 h−1 and a 100% CO selectivity. The findings demonstrate that the growth of anisotropic nanomaterials can be tailored for advanced heterostructure design through oriented attachment alone.

Electronegative diversity induced localized built-in electric field in a single phased MoSxSeyNz for selectivity-enhanced visible photocatalytic CO2 reduction

How to passivate the recombination in a photocatalyst is a big challenge to achieve efficient photocatalytic CO2 reduction. Besides the heterojunction strategy, the design of intrinsic built-in electric field in a single phased photocatalyst can facilitate the transport while it does not introduce extra side reactions induced by the unbalanced photocarriers. This work utilizes the electronegative diversity between chalcogens and non-chalcogen element in a quarternary transition metal dichalcogenide of MoSxSeyNz to define localized built-in electric fields. It has been revealed that the nitrogen induced intrinsic dipole moments and potential energy have strenghthened the built-in electric fields, promoting the separation of photocarriers and the gathering of electrons around N sites, which has been found to improve the adsorption of intermediate products and lower the energy for methanol-oriented photoproduction route. Finally, the MoSxSeyNz has improved the photoproduction of methanol reduced from CO2 by 162%.

Improved charge transfer in polymeric carbon nitride synergistically induced by the aromatic rings modification and Schottky junctions for efficient photocatalytic CO2 reduction

Polymeric carbon nitride (CN) is one of the most prospective non-metallic catalysts at present, yet its photocatalytic activity is unsatisfactory mainly due to the poor intramolecular charge carrier separation efficiency originated form its special electronic structure. Herein, we demonstrate a synergistic strategy to improve the charge carriers transfer and separation efficiency of CN synchronously by extending the π-conjugated system via incorporation of O-containing aromatic ring in the CN skeleton (Ar-CN) and constructing a Schottky junction via decoration of Au nanoparticles (Au Nps). The introduced O-containing aromatic ring can create a local asymmetry, delocalize the π-conjugated system of CN, and thus promote the in-plane charge transport of CN, while the formed loading of Au Nps can further promote interlayer charge transfer efficiency of Ar-CN. The optimized 3 %Au/Ar-CN photocatalyst exhibits a high photocatalytic CO2 activity with a CO yield of 32.03 μmol·g−1·h−1, which is higher than those of CN (2.38 μmol·g−1·h−1) and Ar-CN (6.42 μmol·g−1·h−1). This study provides a feasible co-modification strategy to enhance the charge transfer and photocatalytic activity of CN by extending the π-conjugation system and constructing Schottky junctions.

Construction of a bismuth-based perovskite direct Z-scheme heterojunction Au-Cs3Bi2Br9/V2O5 for efficient photocatalytic CO2 reduction

Photocatalytic reduction of CO2 to the useful fuels has been supposed to be a hopeful approach to address currently environmental and energy problems. However, photocatalytic CO2 reduction using H2O as a proton source always displays the unsatisfactory activity. Herein, a bismuth-based perovskite Z-scheme heterojunction Cs3Bi2Br9/V2O5 with efficient charge separation and strong redox capability was fabricated for photocatalytic CO2 reduction. The optimal Cs3Bi2Br9/V2O5 shows a superior photocatalytic CO2 reduction performance with a CO yield of 37.8 μmol g-1 h-1, which is 5.3 times higher than that of Cs3Bi2Br9. With the further help of the Au cocatalyst, the CO yield of the optimal Au-Cs3Bi2Br9/V2O5 increases to 98.95 μmol g-1 h-1, superior to most reported perovskite photocatalytic CO2 reduction performances. The charge transfer process and the mechanism of photocatalytic CO2 reduction in the Au-Cs3Bi2Br9/V2O5 composite have been thoroughly investigated. This work enriches the perovskite based Z-scheme heterojunctions and expands the application of bismuth-based perovskites in photocatalytic CO2 reduction.