Decoding the Reaction Mechanisms of WS ₂ ‐Confined Atomic Co Sites in Hydrogenation and Hydrogen Production Reactions

ABSTRACT Developing advanced catalysts for hydrogenation and hydrogen production is essential for producing fuels and materials in a sustainable form. However, challenges remain due to the catalysts’ poor activity and limited lifetime. Herein, we report on an efficient atomic editing approach using sulfur‐confined atomic Co atoms on tungsten sulfide nanosheets (Co 1 /WS 2 ) that can effectively break scaling‐limitations. This approach yields improved catalytic performance in achieving transfer hydrogenation of quinoline, exhibiting an excellent yield of 99% toward 1,2,3,4‐tetrahydroquinoline and a record high turnover frequency (TOF) of 3371 h −1 . Importantly, a wide substrate scope and efficient continuous‐flow production are successfully demonstrated. Using Co 1 /WS 2 as a hydrogen evolution reaction (HER) catalyst in acidic media, an ultra‐low overpotential of 19 mV at 10 mA cm −2 and a high operational stability are obtained. Characterizations and computational studies demonstrate that the coordination environments, metal‐support interactions, and charge transfer lead to optimized intermediates and adsorption energies. This not only facilitates the transfer hydrogenation of quinoline with active * H species through the Eley−Rideal mechanism, but also enhances proton transfer and promotes efficient H 2 desorption for HER. This work paves the way for a tailored catalyst design strategy with high atom‐economy that overcomes the dilemma between activity and stability.