Ultrastable monolithic electrodes with single-atom platinum-oxygen sites for efficient hydrogen evolution in acidic conditions.

PtNC single-atom catalysts (SACs) single-atom catalysts (SACs) are promising for acidic hydrogen evolution reaction (HER) but suffer from instability at high current densities, limiting their large-scale application. Herein, PtO bonds are constructed to securely anchor atomically dispersed Pt for single-atom (SA) catalysis, utilizing etched vertical graphene (EVG) nanosheets as monolithic supports (Pt-SAs/EVG). Compared to PtNC, the resultant PtO coordination demonstrates improved stability while maintaining significant catalytic activity. When applying this catalyst in the acidic HER, a high turnover frequency (34.6 s) is achieved at 70 mV, accompanied by exceptional durability exceeding 100 h at -100 mA cm. Theoretical analyses indicate that the PtO bonds confer stability to the Pt atoms, facilitating the efficient adsorption of protons and the subsequent desorption of hydrogen. The prepared Pt-SAs/EVG can also be directly employed as the cathode to afford stable operation at 0.5 A cm in a proton exchange membrane electrolyzer cell. This study offers novel insights into enhancing the performance of SACs for industrial applications in electrocatalysis.