Construction of a highly efficient and durable 1D ternary CdS/ZnS/ Pt nanohybrid catalyst for photocatalytic CO₂ reduction into chemical fuels under solar light irradiation

The conversion of anthropogenic CO₂ to value-added chemicals through solar-driven catalysis has been proposed as a promising approach to overcome the problems associated with high CO₂ emissions and to address the energy crisis. Although a variety of materials have been investigated for catalysts in the production of high-energy fuels from CO₂ in water, the development of efficient and stable nanostructures for long-time operation remains a challenge. In this respect, nanohybrid systems with co-catalysts have been investigated because the reduction of CO₂ requires multiple electrons. Here, we report the unique design of a nanohybrid system consisting of photodeposited Pt nanoparticles on a core−shell structure of CdS/ZnS as a durable catalyst for the reduction of CO₂. This nanohybrid system enhances photoabsorption and accelerates the separation of photogenerated charge carriers, which are evidenced by optical studies. The photocatalytic reaction involved in the reduction of CO₂ is investigated in an aqueous solution, leading to the production of CO and CH₄ with the assistance of triethanolamine as a hole scavenger. The CO and CH₄ production rates by the optimized CdS/ZnS/Pt photocatalyst are ∼50 times higher than those by bare CdS, while the photocatalyst maintains its stability for more than 42 h. The production of H₂ and CH₄ becomes reduced under long-time run with CdS/ZnS/Pt, which selectively produces CO as the major compound. The proposed nanocomposite material successfully achieves solar-to-chemical energy conversion with a quantum yield of 3.5% (λ ≥ 425 nm), demonstrating that it holds promise as a highly efficient and stable photocatalyst of CO₂ reduction to produce carbon fuels under solar light.