Photocatalytic CO-to-Ethylene Conversion over BiS/CdS Heterostructures Constructed via Facile Cation Exchange.

Solar-driven CO conversion to multicarbon (C) 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 BiS/CdS heterostructures via facile cation exchange, by which a unique pathway of CO-to-CH photoconversion is achieved. Specifically, the BCS-30 shows an optimal CH production rate of 3.49 mol h g based on the regulation of band structures and energy levels of photocatalysts by controlled growth of BiS 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 CO conversion towards C products under mild photocatalytic conditions.