Constructing Tunable Strain-Engineered CdS Catalyst toward High Selective CO₂-to-CO Electroreduction

Deciphering the influence of strain environments on the electronic structure of active centers and their adsorption behavior is pivotal for designing highly efficient electrocatalysts. However, precisely manipulating local microstrain to finely regulate the geometric and electronic properties of catalysts remains a formidable challenge. Herein, C, N-incorporated CdS with tunable microstrain levels are constructed via the in situ treatment of Cd₃(C₃N₃S₃)₂ coordination polymers (CdTMT, TMT = 2,4,6-trimercaptotriazine anion). By varying hydrothermal temperatures, different extents of polymer decomposition are induced, resulting in distinct levels of lattice strain. The embedded C atoms introduce tensile strain at Cd sites while acting as electron buffers, enhancing electron localization at these sites. Theoretical analysis reveals electron-rich Cd^δ+ sites, generated through the zmicrostrain effect, reduce the antibonding orbital occupancy of Cd-C_ads, thereby significantly strengthening ^*COOH adsorption, the rate-determining step. The moderately strain-engineered CdTMT-170 catalyst achieves ≈100% Faradaic efficiency for electrochemical CO₂ reduction to CO at industrial-level current density. This study presents an efficient approach to constructing active centers with a tunable microstrain environment, highlighting the effectiveness of strain engineering in designing active CO₂ reduction catalysts.