Boosting Electrochemical Styrene Transformation via Tandem Water Oxidation over a Single-Atom Cr₁ /CoSe₂ Catalyst

Electrocatalytic oxidation of organics using water as the oxygen source is a prospective but challenging method to produce high-value-added chemicals; especially, the competitive oxygen evolution reaction (OER) limits its efficiency. Herein, a tandem catalysis strategy based on a single-atom catalyst with Cr atoms atomically dispersed at a CoSe₂ support (Cr₁ /CoSe₂ ) is presented. Thereinto, Co and Cr sites are endowed with a specific function to activate water and styrene respectively, and the competition between the OER and styrene oxidation is turned into mutual benefits via cooperated active sites. Under a potential of 1.6 V_Ag/AgCl , excellent selectivity of 95% to benzaldehyde and a high conversion rate of styrene at 88% without any exogenous oxidizing reagent are achieved. Isotopic tracing, isotope-labeled in situ Raman spectra, and detailed theoretical calculation further reveal the tandem mechanism, showing that the transfer of *OOH intermediates from the Co to the Cr sites serves as a bridge to link the oxidation of water and styrene. This work develops a new strategy for the co-oxidation of multi-species based on tandem catalysis, providing novel insights for the design of single-atom catalysts.