The roles of gold and silver nanoparticles on ZnIn2S4/silver (gold)/tetra(4-carboxyphenyl)porphyrin iron(III) chloride hybrids in carbon dioxide photoreduction

The construction of hybrid catalysts composed of inorganic semiconductors and molecular catalysts shows great potential for achieving high photocatalytic carbon dioxide (CO₂) conversion efficiency. In this study, ZnIn₂S₄ was first synthesized via a solvothermal route. Gold (Au) and silver (Ag) nanoparticles were then deposited on ZnIn₂S₄ via the reduction of noble metal precursor by sulfur vacancy defects. The obtained composite was further combined with tetra(4-carboxyphenyl)porphyrin iron(III) chloride (FeTCPP) molecular catalyst for efficient photocatalytic CO₂ conversion. The roles of different noble metal nanoparticles in charge separation and interfacial electron transfer have been comprehensively studied. The photocatalytic performance and photoelectrochemical characterizations demonstrate that the introduction of Ag or Au nanoparticles is beneficial for charge separation. More importantly, the presence of Ag nanoparticles plays a crucial role in promoting the interfacial charge transfer between ZnIn₂S₄ and FeTCPP, whereas, Au nanoparticles function as active sites for the water reduction reaction.

Atomic heterojunction-induced accelerated charge transfer for boosted photocatalytic hydrogen evolution over 1D CdS nanorod/2D ZnIn2S4 nanosheet composites

Design of highly efficient heterojunctions for photocatalytic hydrogen evolution is of significant importance to address the energy shortage and environmental crisis. Nevertheless, the smart design of semiconductor-based heterojunctions at the atomic scale still remains a significant challenge hitherto. Herein, we report novel atomic CdS/ZnIn₂S₄ heterojunctions by in-situ epitaxially growing 2D ZnIn₂S₄ nanosheets onto the surface of 1D defective CdS nanorods. The strong electronic coupling between defective CdS and ZnIn₂S₄ is confirmed by transient photocurrent response measurements, •O₂^- and •OH radicals experiments, and PL results, leading to accelerated interfacial charge separation and transfer. Additionally, the elevated charge transfer and electronic coupling are further confirmed by theoretical calculations. Consequently, CdS/ZnIn₂S₄ hybrids exhibit superior photocatalytic hydrogen generation activity to pristine CdS. Our findings offer a new paradigm for designing atomic 1D/2D heterojunctions for efficient solar-driven energy conversion.

CuMoxW(1-x)O4 Solid Solution Display Visible Light Photoreduction of CO2 to CH3OH Coupling with Oxidation of Amine to Imine

The photoreduction of carbon dioxide (CO₂) to valuable fuels is a promising strategy for the prevention of rising atmospheric levels of CO₂ and the depletion of fossil fuel reserves. However, most reported photocatalysts are only active in the ultraviolet region, which necessitates co-catalysts and sacrificial agents in the reaction systems, leading to an unsatisfied economy of the process in energy and atoms. In this research, a CuMo_xW_(1-x)O₄ solid solution was synthesized, characterized, and tested for the photocatalytic reduction of CO₂ in the presence of amines. The results revealed that the yield of CH₃OH from CO₂ was 1017.7 μmol/g under 24 h visible light irradiation using CuW_0.7Mo_0.3O₄ (x = 0.7) as the catalyst. This was associated with the maximum conversion (82.1%) of benzylamine to N-benzylidene benzylamine with high selectivity (>99%). These results give new insight into the photocatalytic reduction of CO₂ for valuable chemical products in an economic way.

Vacancy induced photocatalytic activity of La doped In(OH)3 for CO2 reduction with water vapor

A possible mechanism to explain the impact of La doping on electron transfer process in wide band gap semiconductor In(OH)₃.

In Situ Grown Monolayer N-Doped Graphene on CdS Hollow Spheres with Seamless Contact for Photocatalytic CO2 Reduction

Photocatalytic CO₂ reduction is an effective way to simultaneously mitigate the greenhouse effect and the energy crisis. Herein, CdS hollow spheres, on which monolayer nitrogen-doped graphene is in situ grown by chemical vapor deposition, are applied for realizing effective photocatalytic CO₂ reduction. The constructed photocatalyst possesses a hollow interior for strengthening light absorption, a thin shell for shortening the electron migration distance, tight adhesion for facilitating separation and transfer of carriers, and a monolayer nitrogen-doped graphene surface for adsorbing and activating CO₂ molecules. Achieving seamless contact between a photocatalyst and a cocatalyst, which provides a pollution-free and large-area transport interface for carriers, is an effective strategy for improving the photocatalytic CO₂ reduction performance. Therefore, the yield of CO and CH₄ , as dominating products, can be increased by four and five times than that of pristine CdS hollow spheres, respectively. This work emphasizes the importance of contact interface regulation between the photocatalyst and the cocatalyst and provides new ideas for the seamless and large-area contact of heterojunctions.

Design of atomically dispersed catalytic sites for photocatalytic CO2 reduction

Photocatalytic conversion of CO₂ into carbonaceous chemical fuels and building blocks is an intriguing strategy for solving fossil energy crisis and reducing CO₂ emission. Recently, development of atomically dispersed catalytic sites for photocatalytic CO₂ reduction has sparked tremendous interest as their coordinatively unsaturated states, tunable electronic structures and well-defined active sites provide versatile knobs for tuning CO₂ conversion. While this Minireview mainly highlights recent key developments in this important research field and elucidates the common fundamentals behind various materials systems, it also provides insights into the future development and emphasizes opportunities and challenges.