Synergistic Acid Hydrogen Evolution of Neighboring Pt Single Atoms and Clusters: Understanding Their Superior Activity and Mechanism

The hydrogen evolution reaction (HER) involves two-step elementary reactions, providing an opportunity to establish dual-site synergistic catalysts. This work demonstrates carbon-supported Pt single atoms and clusters (Pt1+Cs-NPC) as an efficient catalyst for acidic HER, which exhibits an ultralow Tafel slope of 12.5 mV/dec and an overpotential of 24 mV at 10 mA/ cm2 with an ultralow platinum content of 3.8 wt %. The Pt mass activity and turnover frequency (TOF) are 10.2 times and 5.4 times that of commercial Pt/C, respectively. The density functional theory (DFT) study shows that the Pt cluster regulates the electronic state structure of the adjacent Pt single atom, so that the Delta GH* at the Pt1 site approaches 0. Moreover, the DFT study confirms that Pt clusters and neighboring Pt single atoms can synergistically catalyze the Tafel step and reduce the energy barrier in forming the H-H bond. At the same time, the platinum cluster reduces the energy barrier of the nearby platinum single-atom site to the Heyrovsky step and accelerates the reaction with hydrated hydrogen ions. Studies have shown that platinum clusters and platinum single-atom composite loading structures exhibit excellent activity for the Volmer-Tafel or Volmer-Heyrovsky reaction paths of HER reactions. This work provides a clear understanding of the synergistic effect of Pt1+Cs-NPC, which provides guidance for developing efficient HER catalysts.

Automated summary

This study reveals the influence of Pt and Ru loading and PtRu alloy modification on the catalytic performance of Cu(111) electrodes through oxygen isotope tracing experiments and computational theoretical calculations. The results show that Pt loading increases the surface H-adsorption activity of Cu and has an independent activation energy route, while Ru loading enhances the adsorption strength of H2O on Pt surface and promotes hydrogen evolution. Based on this finding, a PtRu/Cu(111) catalyst is constructed in this study, and the molar ratio between Pt and Ru is optimized to achieve the best catalytic performance.