Photocatalytic Conversion Of CO2 Research Articles

3D ZnO hollow spheres-dispersed CsPbBr3 quantum dots S-scheme heterojunctions for high-efficient CO2 photoreduction

Efficient electron transfer process and excellent CO2 adsorption capacity are of great significance for improving CO2 photoreduction efficiency. 3D-0D ZnO/CsPbBr3 S-scheme heterojunction hollow spheres were successfully prepared via a simple self-assembled process for efficient CO2 photoreduction. Photocatalytic CO2 reduction experiments showed that the ZnO/CsPbBr3 had the excellent CO2 photocatalytic conversion activity to CO, which was about 2.61 times higher than that of ZnO hollow micro-spheres and 1.9 times higher than that of pure CsPbBr3 quantum dots (QDs). Photoelectrochemical characterization confirmed that the ZnO/CsPbBr3 composite had good photoelectric conversion ability and carrier transfer ability, which was beneficial to the photocatalytic reaction. The suitable band gap structure and DFT calculation results showed that the formation of built-in electric field at the ZnO/CsPbBr3 interface can greatly improve the S-scheme electron transfer ability, which can foster the CO2 photoreduction. Besides, the introduction of 3D structure can improve the dispersion of CsPbBr3 QDs and effectively enhance the CO2 capture ability of the catalyst, which greatly promoted the CO2 photoreduction reaction. The current work can present a novel S-scheme photocatalyst, which is looked forward to providing a certain perception into the advance of novel highly efficient CsPbBr3 QDs-based photocatalysts for CO2 resource utilization.

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.

Polymeric carbon nitride loaded with atomic Cu sites for improved CO2 photocatalytic conversion performance

CO2 photocatalytic conversion has been considered as a promising strategy to reduce CO2 level and produce chemical feedstocks. However, developing highly efficient photocatalysts still remains a challenge. Here, copper (Cu) single atom sites (SAs) have been loaded into polymeric carbon nitride (CN) framework through one-step thermal polymerization method. The Cu sites loaded in CN framework can not only enhance the visible light absorption, but also accelerate the mobility of charge carriers. The range of light absorption can be extended to a longer wavelength, and the recombination of photogenerated electron and hole pairs can be considerably suppressed. Furthermore, the valence band of obtained photocatalysts shift more negative with Cu loading, resulting in stronger reduction potential for CO2 photocatalytic conversion. As a result, the CO2 photocatalytic activity can be considerably enhanced a lot. By regulating the content of Cu, the CO production amount (1.62 μmol/g.h) can be enhanced 2.7 times higher than that of bulk CN (0.6 μmol/g.h). This work proposes a facile and eco-friendly way to modify CN photocatalyst, which is inspiring to design high efficiency photocatalysts.

Synergistic effects of heterointerface and surface Br vacancies in ultrathin 2D/2D H2WO4/Cs2AgBiBr6 for efficient CO2 photoreduction to CH4

Efficient photocatalytic conversion of CO2 to CH4 is challenging due to the complex eight-electron coupled proton transfer process. Herein, a 2D/2D H2WO4/Cs2AgBiBr6 (HWO/CABB) heterojunction was fabricated specifically through the “top-down” acid cleavage of layered Bi2WO6 (Bi2O2-WO4) into 2D HWO nanosheet, followed by the in-situ “bottom-up” epitaxial growth of 2D CABB on HWO nanosheet. Detailed characterizations revealed that HWO/CABB possessed abundant surface Br-vacancies (VBr) with an ultrathin 2D/2D heterointerface involving Bi-O and Ag-O bonds, facilitating charge transfer via an S-scheme. Density functional theory (DFT) calculations demonstrated that VBr could promote the adsorption/activation of CO2 and reduce the formation energy barrier of CHO* significantly. Therefore, HWO/CABB exhibited an enhanced CH4 production rate of 22.6 µmol·g−1·h−1 (the electron selectivity of 86.1%), approximately 30 times higher than that of pristine CABB. Furthermore, a plausible mechanism of photocatalytic CO2 to CH4 was proposed based on in-situ diffuse reflectance infrared spectroscopy and DFT calculations. This work demonstrates the potential of heterointerface and surface defects in synergistically tailoring CO2 selective reduction on halide perovskite photocatalysts.

In Situ Growth of Lead-Free Cs2CuBr4 Perovskite Quantum Dots in KIT-6 Mesoporous Molecular Sieve for CO2 Adsorption, Activation, and Reduction.

Metal halide perovskites (MHPs) are emerging as promising candidates for photocatalytic CO2 conversion. However, their practical application is still restricted by the poor intrinsic stability and weak adsorption/activation toward CO2 molecules. The rational design of MHPs-based heterostructures with high stability and abundant active sites is a potential solution to this obstacle. Herein, we report the in situ growth of lead-free Cs2CuBr4 perovskite quantum dots (PQDs) in KIT-6 mesoporous molecular sieve, obtaining remarkable photocatalytic CO2 reduction activity and durable stability. The optimized Cs2CuBr4@KIT-6 heterostructure exhibits the photocatalytic CO and CH4 evolution rates of 51.6 and 17.2 μmol g-1 h-1, respectively, far exceeding those of pristine Cs2CuBr4. On the basis of in situ diffuse reflectance infrared Fourier transform spectra and theoretical investigations, the detailed CO2 photoreduction pathway is systematically revealed. This work provides a new route for the rational construction of perovskite-based heterostructures with strong CO2 adsorption/activation and good stability for photocatalytic CO2 reduction.

Highly efficient photocatalytic conversion of CO2 into CH4 over Cu single atom promoted heterojunction: The effect of uplifted d-band center

Photoreduction of CO2 to solar fuels has caused great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, we designed a S-scheme heterojunction (Cu-TiO2/WO3) with Cu single atom to significantly boost the photoreduction of CO2. Notably, the developed Cu-TiO2/WO3 achieved the solar-driven conversion of CO2 to CH4 with an evolution rate of 98.69 µmol g−1 h−1, and the electron selectivity of CH4 reached 88.5%. The yield was much higher than those of pristine WO3, TiO2/WO3 and Cu-TiO2 samples. Experimental and theoretical analysis suggested that the S-scheme heterojunction accelerated charge migration and inhibited the recombination of electron-hole pairs. Importantly, the charge separation effect of the heterojunction meliorated the position of the d-band. The uplifted d-band centers of Cu and Ti on Cu-TiO2/WO3 not only improved the electron interaction between Cu single atoms and substrate-TiO2, accelerated the adsorption and activation of CO2 on the active sites of Cu single atom, but also optimized the Gibbs free energies of CH4 formation pathway, leading to excellent selectivity toward CH4. This work provides new insights into the design of photocatalyst systems with high photocatalytic performance.

Near-Infrared-Responsive Photocatalytic CO2 Conversion via In Situ Generated Co3O4/Cu2O.

Photocatalytic CO2 conversion to fuels is a promising strategy for achieving global carbon neutrality. However, infrared light, which accounts for ∼50% of the full sunlight spectrum, has not yet been effectively utilized via photocatalysis. Here, we present an approach to directly power photocatalytic CO2 reduction using near-infrared light. This near-infrared light-responsive process occurs on an in situ generated Co3O4/Cu2O photocatalyst with a nanobranch structure. Photoassisted Kelvin probe force microscopy and relative photocatalytic measurements demonstrate the increase of surface photovoltage after illumination by near-infrared light. We also find that Cu(I) on this in situ generated Co3O4/Cu2O could facilitate the formation of a *CHO intermediate, thus enabling a high-performance CH4 production with a yield of 6.5 μmol/h and a selectivity of 99%. Moreover, we perform a practically oriented direct solar-driven photocatalytic CO2 reduction under concentrated sunlight and achieve a fuel yield of 12.5 μmol/h.

Highly Selective Photosynthesis of Formic Acid by Unifying the Products of CO2 Reduction and Methanol Oxidation

Photocatalytic conversion of CO2 to added‐value fuels or chemicals is a promising technology for the effective utilization of the disturbing greenhouse gas, but its economic benefit is limited either by low efficiency due to the difficulty of water oxidation or by the employment of expensive sacrificial reagents. To overcome this dilemma, herein, an effective strategy is reported for the resourceful utilization of CO2 by creating an eco‐friendly bifunctional photocatalyst to achieve CO2 photoreduction concurrent with methanol photooxidation to the uniform product of formic acid for the first time. The bifunctional photocatalyst is elaborately constructed by in situ encapsulating lead‐free double perovskite (Cs2AgBiBr6, abbreviated as CABB) nanocrystals into the pores of Fe‐based metal−organic framework (MIL‐101(Fe)). The tight contact between CABB and MIL‐101(Fe) in the resultant CABB/MIL‐101(Fe) composite facilitates the efficient spatial separation of photogenerated carriers, which leads to the division of reduction and oxidation functional units. CABB/MIL‐101(Fe) composites can unify the redox products into formic acid, reaching an impressive formation yield of 1375 μmol g−1 h−1 with a high selectivity of 97.8%. This work provides a viable strategy for the efficient photosynthesis of formic acid, promoting the cost‐effective utilization of CO2.

Doping Sn4+ ionized cocatalyst in CdSe/S colloidal crystal for promoting photocatalytic CO2 reduction under visible light

The exploration of low-cost and efficient cocatalysts is vitally important for attaining reliable and affordable photocatalytic CO2 conversion. Here, it is found that post-transition metal ions (Sn4+) doped CdSe/S colloidal crystal can serve as effective photocatalyst for CO2 reduction under visible light, in which Sn4+ serves as an ionized cocatalyst. Specifically, Sn4+ doped CdSe/S colloidal crystal shows an improved and stable photocatalytic CO2 reduction performance with CO generation rate of 50.3 μmol h−1 and H2 generation rate of 7.8 μmol h−1 in the presence of triethanolamine as sacrificial agent. The improved photocatalytic activity can be ascribed to the increased light harvesting ability, enhanced CO2 adsorption capability and the improved surface charge transfer efficiency induced by Sn4+ dopant.

Z-scheme heterojunction of chemically integrated COF-366-Co/UiO-66-NH2 MOFs nanocomposites for selective production of CO via CO2 solar-drive photoreduction

The photocatalytic conversion of CO2 to renewable fuel using solar energy has recently become an interesting topic, owing to its potential to replace fossil fuels. However, the low efficiency and selectivity of photocatalysis hinder the development of this method for practical applications. In this work, a composite photocatalyst composed of UiO-66-NH2 and COF-366-Co materials is developed using a facile synthetic route with varying concentrations of UiO-66-NH2. The optimized COF-366-Co/UiO-66-NH2 composite exhibited a remarkable efficiency of CO2 photoreduction toward the CO production, reaching ∼ 4092.16 µmol. g-1.h-1 at the end of 4 h, which is around 2.37 times higher than the bare COF, while maintaining a significant CO selectivity at ca 73.28 %. The apparent quantum yield (AQY) of the composite photocatalyst is estimated to be ∼2.4 %. at 400 nm, which is one of the promising values in the CO2 photoreduction reaction. Parametric studies by varying various components revealed the key mechanism of the photoreduction process. The electrochemical impedance, time-resolved, steady state photoluminescence, linear sweep voltammetry and photocurrent measurements of the systems revealed that the incorporation of UiO-66-NH2 to COF-366-Co has enhanced the properties of the system by improving the lifetime of the excited carriers via electron delocalization and transfer of carriers to the adsorbed CO2 for their effective reduction to CO. Furthermore, the estimated band edge potential of the systems using Mott-Schottky plots suggested that there could be a Z-scheme formation, which mediates the charge transfer at the junction towards achieving an enhanced CO2 photoreduction efficiency and selectivity. This research could promote the development of porphyrin-based COF/MOF-based composites for selective CO2 photoconversion into value-added chemicals and fuels.

Microwave-assisted construction of Bi2MoO6/g-C3N4 heterostructure for boosting photocatalytic CO2 conversion

Photocatalytic CO2 reduction can simultaneously alleviate the energy crisis and solve environmental issues. Nevertheless, it is still challenging for designing photocatalysts with efficient carrier mobility in rational. Herein, the Bi2MoO6/g-C3N4 (BMO/CN) heterostructure was constructed through a microwave-assisted which could enhance the construction of two-dimensional and two-dimensional (2D/2D) structures. The 2D/2D BMO/CN heterojunction possessed excellent charge separation efficiency which exhibited superior performance on photocatalytic CO2 reduction. It was shown by the characterization that the (131) surface of Bi2MoO6 was constructed with the (100) surface of g-C3N4. The work functions of Bi2MoO6 and g-C3N4 were determined to be 4.57 and 4.22 eV, respectively, which suggested the type-II heterojunction was formed. The formation of CO and CH3OH over the optimized BMO/CN-30% catalyst reached 2.44 and 3.61 µmol⋅g−1⋅h−1, respectively. The immediate products of HCO3- were observed within in-situ FT-IR to further certify the evolution of CH3OH. This work highlighted a microwave-assisted strategy to build a heterojunction structure for enhancing photoreduction CO2.

Vacancy defects engineering in Yolk-shelled Co-CeO2 for efficient visible Light-Driven CO2 reduction

Solar-driven photocatalytic CO2 conversion is considered as the most promising approach to eliminating atmospheric CO2 emissions. However, great challenges lie in the utilization of visible-infrared light and the activation of the inert CO2 molecule. Herein, we report the preparation of a yolk-shell Co-CeO2 octahedron and the strategy for surface defect engineering to optimize the photocatalyst by two-step calcination of a Ce-based metal–organic framework (Ce-UiO-66). As a result of the synergistic effect of incorporating the Co atom and rich oxygen vacancies, the energy barrier of activating and transforming the adsorbed CO2 to *COOH is significantly reduced. Benefiting from the structure with high surface area, cavity, and abundant defects, the optimized Co-CeO2 photocatalyst not only provides more exposed active sites and enhanced photoabsorption but also improves charge separation and transfer. Accordingly, 1%–Co-CeO2-H2 exhibits much higher photocatalytic activity in CO2 reduction under visible light irradiation with a CO generation rate of 46.9 μmol/h, which is 4.6 times than that of less defective 1%–Co-CeO2, and far more than that of pure CeO2.

Tailoring defects in In2S3/Zn0.3Cd0.7S heterojunctions for efficient photocatalytic CO2 conversion

Defect engineering is a highly effective approach to regulate the electronic structure of the catalyst surface, widely employed in the field of photocatalytic energy conversion. In this study, we have successfully synthesized a novel dual-defective In2S3/Zn0.3Cd0.7S (IS/ZCS) heterojunction structure via a self-assembly method, composed of Zn-vacancy-rich Zn0.3Cd0.7S (ZCS) and S-vacancy-rich In2S3 (IS). Under visible light illumination, 3% IS/ZCS sample exhibits remarkable photocatalytic performance in the synergistic reaction of CO2 reduction and 4-chlorobenzyl alcohol (Cl-PhCH2OH) oxidation with the CO yield significantly improved by a factor of 3.5 and 51 compared to that of ZCS and IS, respectively. The combined experimental data and theoretical calculations demonstrate that the dual-defective structure and Z-scheme transfer mode are the key factors behind the enhanced photocatalytic activity, providing more active sites and effectively improving the utilization of photogenerated charge carriers (PCCs). Moreover, the reaction pathway and catalytic mechanism of photocatalytic CO2 reduction were elucidated by the in-situ FTIR technique combined with DFT calculations, monitoring the intermediate and final products during the reaction period. Our results provide a powerful example of designing novel heterojunction photocatalysts with high activity and accelerating the separation of PCCs, with broad implications for the development of efficient photocatalytic systems.

Oxygen Vacancy-Rich S-Scheme CeO2@Ni1–xCoxSe2 Hollow Spheres Derived from NiCo-MOF for Remarkable Photocatalytic CO2 Conversion

Photocatalytic CO2 conversion into chemicals has been a promising strategy to utilize sustainable solar energy and alleviate the greenhouse effect. Nonetheless, the achievements of these photocatalytic reactions are challenging. Herein, we present a strategy for the synthesis of hierarchical CeO2@Ni1–xCoxSe2 hollow spheres (HSs) including the successive steps of coating of the CeO2 nanolayer on SiO2 spheres, in situ growth of NiCo-MOF nanosheets, selenization reaction, and subsequent etching treatment. The hierarchical CeO2@Ni1–xCoxSe2 HSs exhibiting intimate interface contact between two nanoshells form an S-scheme heterojunction with fast charge/mass transport and excellent visible-light absorption, while maintaining the strong reducing power of electrons in the conduction band of Ni1–xCoxSe2 nanosheets and the strong oxidizing capacity of holes in the valence band of CeO2 HSs with oxygen vacancies. The S-scheme photogenerated charge transfer mechanism was testified by the work function and electron paramagnetic resonance measurements. These advantages make the optimized CeO2@Ni1–xCoxSe2 HS sample exhibit superior activity and high stability in photocatalytic CO2 reduction with a CO production rate of 25.93 μmol h–1 g–1. This work provides more opportunities to fabricate other hierarchical S-scheme semiconductor-based photocatalysts.

Tunable Interfacial Charge Transfer in a 2D-2D Composite for Efficient Visible-Light-Driven CO2 Conversion.

Photocatalytic CO2 conversion for hydrocarbon fuel production has been known as one of the most promising strategies for achieving carbon neutrality. Yet, its conversion efficiency remains unsatisfactory mainly due to its severe charge-transfer resistance and slow charge kinetics. Herein, a tunable interfacial charge transfer on an oxygen-vacancies-modified bismuth molybdate nanoflower assembled by 2D nanosheets (BMOVs) and 2D bismuthene composite (Bi/BMOVs) is demonstrated for photocatalytic CO2 conversion. Specifically, the meticulous design of the Ohmic contact formed between BMOVs and bismuthene can allow the modulation of the interfacial charge-transfer resistance. According to density functional theory (DFT) simulations, it is ascertained that such exceptional charge kinetics is attributed to the tunable built-in electric field (IEF) of the Ohmic contact. As such, the photocatalytic CO2 reduction performance of the optimized Bi/BMOVs (CO and CH4 productions rate of 169.93 and 4.65µmol g-1 h-1 , respectively) is ca. 10 times higher than that of the pristine BMO (CO and CH4 production rates of 16.06 and 0.51µmol g-1 h-1 , respectively). The tunable interfacial resistance of the Ohmic contact reported in this work can shed some important light on the design of highly efficient photocatalysts for both energy and environmental applications.

Hierarchical Hollow-TiO2@CdS/ZnS Hybrid for Solar-Driven CO2-Selective Conversion.

Light-driven valorization conversion of CO2 is an encouraging carbon-negative pathway that shifts energy-reliance from fossil fuels to renewables. Herein, a hierarchical urchin-like hollow-TiO2@CdS/ZnS (HTO@CdS/ZnS) Z-scheme hybrid synthesized by an in situ self-assembly strategy presents superior photocatalytic CO2-to-CO activity with nearly 100% selectivity. Specifically, benefitting from the reasonable architectural and interface design, as well as surface modification, this benchmarked visible-light-driven photocatalyst achieves a CO output of 62.2 μmol·h-1 and a record apparent quantum yield of 6.54% with the Co(bpy)32+ (bpy = 2,2'-bipyridine) cocatalyst. It rivals all the incumbent selective photocatalytic conversion of CO2 to CO in the CH3CN/H2O/TEOA reaction systems. Specifically, the addition of HTO and stabilized ZnS enables the photocatalyst to effectively upgrade optical and electrical performances, contributing to efficient light-harvesting and photogenerated carrier separation, as well as interfacial charge transfer. The tremendous enhancement of photocatalytic performance reveals the superiority of the Z-scheme heterojunction assembled from HTO and CdS/ZnS, featuring the inner electric field derived from the band bending of HTO@CdS/ZnS make CdS resistant to photocorrosion. This study allows access to inspire studies on rationally modeling and constructing diverse heterostructures for the storage and conversion of renewables and chemicals.

S-Scheme-Heterojunction LaNiO3/CdLa2S4 Photocatalyst for Solar-Driven CO2-to-CO Conversion

Visible-light-driven semiconductor-catalyzed CO2 conversion into valuable chemicals and industrial feedstocks is one of the superior pathways to address the excess carbon emissions and energy shortages. Herein, an innovative step-scheme (S-scheme) heterojunction assembled from bulk CdLa2S4 and surface rare-earth perovskite-type oxide LaNiO3 with precisely engineered suitable band alignment is employed for the selective photocatalytic conversion of CO2 to CO. The optimized 8%-LaNiO3/CdLa2S4 photocatalyst exhibits an outstanding CO output of up to 102.43 μmol h–1 with a selectivity of about 83.4%, rivaling all of the similar incumbent photocatalytic reaction systems for CO2-to-CO conversion. It highlights the effectiveness of the S-scheme heterojunction LaNiO3/CdLa2S4 in hindering the recombination of the photogenerated electron–hole pairs. Meanwhile, a remarkable apparent quantum efficiency (AQE) of as high as 6.76% is achieved, as well as the CO output is still maintained at 99.5% of the initial value after five cycle tests, revealing the superior repeatability and reliability of the 8%-LaNiO3/CdLa2S4 photocatalyst for solar-to-chemical conversion. In addition, an experimentally verified band alignment-boosted reaction mechanism is proposed. This study highlights the construction of structurally flexible and highly designable S-scheme heterojunctions, demonstrating potential application in carbon-negative energy conversion.

Kinetic Study of Heterogeneous Photocatalytic CO2 Reduction: Development of a General Formula for Relations between Activity and Reaction Conditions

Recently, the development of technologies for CO2 emission reduction has been extensively investigated to achieve the global 2 °C climate stabilization target. This study demonstrates that the photocatalytic activity and selectivity toward carbon monoxide (CO) evolution for the selective photocatalytic conversion of CO2 to CO, using H2O as an electron donor, are significantly dependent on the reaction conditions, such as additive concentration, CO2 partial pressure, and reaction temperature. The systematic experiments performed in this study revealed that the CO formation rate was proportional to the increase in the CO2 partial pressure and inversely proportional to the proton (H+) concentration in the reaction solution. Based on these results, a quantitative expression for the formation rate of CO with CO2 partial pressure and pH as variables was developed using kinetics, considering the equilibria of surface hydroxyl groups. This study confirmed that the derived mathematical expressions matched well with the experimental results of three different photocatalysts, whose activities and selectivities were completely different. Moreover, based on these expressions, a theoretical method is proposed to determine the kinetic constant and activation energy for the reduction of adsorbed CO2 molecules. The developed mathematical expression for photocatalytic CO2 conversation in water contributes to the development of CO2 recycling technologies.

Enhanced Adsorption and Dissociation of H2O Facilitates Photocatalytic CO2 Reduction on Defective BiSbO4

The dissociation of H2O molecules plays an important role in producing protons for promoting hydrogenation reduction of CO2. Therefore, developing excellent photocatalysts to promote the dissociation of H2O molecules and reveal the effect mechanism is the key research direction to enhance CO2 reduction efficiency. In this work, we synthesized BiSbO4 with oxygen vacancies (OVs) to investigate the photocatalytic mechanism of CO2 conversion and H2O dissociation. Experimental results indicate that the introduction of OVs into BiSbO4 can enhance the absorption capacity of light, narrowing band gaps and impeding the recombination of photogenerated carriers. Importantly, the existence of OVs in BiSbO4 can promote the adsorption and activation of H2O molecules via the stronger covalent interaction, which facilitates the dissociation of H2O molecules to generate more protons and lowers the energy barriers of •COOH to improve the efficiency of CO2 reduction. This study reinforces our understanding of the principle of photocatalytic CO2 reduction and the important role of H2O dissociation in photocatalytic CO2 conversion.

Photoinduced deposition of AuCu cocatalyst and polyaniline conducting layer on graphitic-C3N4 for enhanced CO2 photoreduction

Photocatalytic CO2 conversion into solar fuel is of great significance for addressing energy crisis and climate change, but this process is generally hampered by insufficient electron deliverability and sluggish reaction kinetics. Herein, polyaniline (PANI) conducting layer and AuCu alloy cocatalyst are successively deposited on graphitic carbon nitride (g-C3N4) nanoflakes via a two-step photoinduced process, to fabricate an AuCu/PANI/g-C3N4 heterostructure photocatalyst. The presence of PANI layer improves electron deliverability and CO2 adsorption capacity of photocatalyst. The AuCu cocatalyst affords efficient active sites for accelerating the reaction kinetics of CO2 photoreduction, and the surface plasmon resonance (SPR) of Au further enhances light utilization and charge separation. Benefiting from these merits, the AuCu/PANI/g-C3N4 photocatalyst exhibits a superior performance toward CO2 reduction with 100% CO selectivity, affording a CO production rate of 9.2 μmol·gcat−1·h−1 under simulated sunlight, which is 1.3 times that from AuCu/g-C3N4 and 2.3 times that from PANI/g-C3N4, respectively. The photocatalytic CO2 reduction mechanism of AuCu/PANI/g-C3N4 catalyst is investigated by a series of control experiments and in-situ infrared spectroscopy. This study demonstrates a rational construction of heterogeneous photocatalysts and highlights the synergistic effect of multiple components in enhancing CO2 photoreduction.