Coordination structure regulation of Pt-NxOy-S1 catalytic sites for promoting high-efficiency hydrogen evolution

The development of atomically dispersed platinum-based catalysts with high performance and well-defined active site structures is crucial for the commercialization of water electrolysis for hydrogen production. Herein, we propose a coordination dual-shell synergistic regulation mechanism of coal pitch-derived carbon-supported single atom Pt-N x O y -S 1 catalytic sites by a self-assembly-pyrolysis strategy for promoting hydrogen evolution reaction (HER). The Pt-N 3 O 1 -S 1 sites exhibited the highest HER performance, with an overpotential of 92 mV at a current density of 400 mA cm −2 . At 50 mV, the turnover frequency was 34.04 s −1 and the mass activity was 22.83 A mg Pt −1 , which is 63.4 times that of the 20% Pt/C catalyst. Theoretical calculations revealed that the coordination dual-shell impacts the electronic structure of the Pt atoms and the adsorption strength towards reactants synergistically. The S atoms in the second coordination shell weakened the strength of Pt-N first shell, resulting the more surface valence electrons around Pt atoms, exhibiting the most suitable adsorption free energy and enhancing the adsorption of H + on Pt-N 3 O 1 -S 1 sites, thus enhancing the electrocatalytic HER process by promoting Volmer step. This work reveals that coordination dual-shell synergistic regulation is an effective strategy for enhancing the electrocatalytic reaction process.