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.