K-mediated peripheral electronic tuning of low-valence Au single atoms for efficient acetylene hydrochlorination

Abstract

Gold single-atom catalysts hold great promise for acetylene hydrochlorination, yet their practical application is hindered by the instability and reduction tendency of high-valence Au species. Herein, we report a K-mediated peripheral electron regulation strategy for the construction of stable low-valence Au single-atom catalysts on nitrogen-doped carbon supports (Au/K-NC-SA). During a 400-hour stability test, the catalyst achieved a reaction rate of 812.1 kg_VCM kg_Au⁻¹ h⁻¹ and a deactivation rate of (7.6 ± 0.2) × 10⁻³% h⁻¹. As an electron donor, K reduces the average oxidation state of Au, increases the electron density of Au 5d orbitals and upshifts the d-band center. This further strengthens the adsorption of acetylene and hydrogen chloride, stabilizes the key transition state, and reduces the energy barrier of the rate-determining step by 0.28 eV. Beyond providing a highly active and stable catalyst, this work deciphers the synergistic mechanism of electronic and field effects in the “K-mediated peripheral effect”, offering a general design principle for stabilizing single-atom catalysts with tailored electronic states, providing a feasible technical scheme for the green transformation of the coal-based polyvinyl chloride industry and aligning with the core principles of green chemistry.