Topologically transformed CoSe2 for enhanced ethanol electrolysis in high-efficiency water splitting and zinc–ethanol–air batteries

Spin engineering has garnered significant attention due to its ability to modulate the interaction between active sites and reaction intermediates, thereby enhancing catalytic kinetics. In this study, we present a strategy to tune the coordination environment of Co via topological transformation, effectively modulating its spin state. The resulting CoSexOy-200 exhibited enhanced catalytic kinetics toward ethanol oxidation reaction, achieving a current density of 10 mA cm−2 at a low potential of 1.34 V. The improved catalytic performance is attributed to a topochemical transition-induced spin reconstruction, optimizing the adsorption of reaction intermediates. Building on these findings, the catalyst was further applied to a zinc–ethanol–air battery, leading to a decrease in charging voltage and a narrowed charge–discharge voltage window, which is less than 650 mV. This study establishes a controllable spin-state modulation strategy via topochemical transformation, paving the way for the rational design of advanced electrocatalyst for water electrolysis and next-generation zinc–ethanol–air batteries.