Photocatalytic CO2–to–Ethylene Conversion over Bi2S3/CdS Heterostructures Constructed via Facile Cation Exchange

Abstract

Solar-driven CO2 conversion to multicarbon (C2+) products has emerged as a key challenge, yet this calls for a systematic investigation on the overall reaction process and mechanism at an atomic level based on the rational design of highly selective photocatalysts. Herein, we report the synthesis of compact Bi2S3/CdS heterostructures via facile cation exchange, by which a unique pathway of CO2–to–C2H4 photoconversion is achieved. Specifically, the BCS–30 shows an optimal C2H4 production rate of 3.49 μmol h−1 g−1 based on the regulation of band structures and energy levels of photocatalysts by controlled growth of Bi2S3 at CdS surface. Both experimental and theoretical results (DFT calculations) identify Bi atoms as new catalytic sites for the adsorption of CO∗ and formation of ∗CO−∗CO dimers that further hydrogenate to produce ethylene. Overall, this work demonstrates vast potentials of delicately designed heterostructures for CO2 conversion towards C2+ products under mild photocatalytic conditions.