Metal edge confined platinum atoms in metal/hydroxide hierarchy structure for multiple hydrogen conversion and evolution

Abstract

Single-atom catalysts (SACs), as a thriving subfield of catalysis, have progressed tremendously. However, the contradiction between the isolated dispersion feature of metal sites and the high mass-specific activity of the catalyst inhibits the advances of the SACs. Herein, the Pt atoms are confined at the metallic Co phase edge in two-dimensional Co/Co(OH)2 hierarchy structure (PtSA-Co@Co-Co(OH)2) by the defect inducted order electrodeposition strategy. Both integrations of in-situ/ex-situ experimental characterizations and theoretical calculation reveal that such metal edge confined Pt atoms possess an enlarged atom exposure ratio, high stability, and the like-metal electronic state contributed by metal Co 3d, which enables the Pt atoms with more suitable affinity to simultaneously bind the multiple H atoms for durable H*-H2 conversion and H2 evolution. Moreover, the metallic PtSA-Co collaborated Co/Co(OH)2 interfaces demonstrate a strong H2O dissociation capacity by the preference adsorption of H* on metallic PtSA-Co and OH*on Co/Co(OH)2 interfaces. Combining a further enhancement of constructing the catalysts on an Ag nanowire network to form a seamlessly conductive nanostructure, the PtSA-Co@Co-Co(OH)2 achieves a high mass activity with 5.92 A mg−1 at the overpotential of 100 mV in alkaline condition, 37 times to that of the benchmark Pt/C catalyst and significantly outperforming the reported catalysts. While our work has focused on the hydrogen evolution reaction, this class of metal edge collaborated single-atom catalysts may be conducive to unlock the low mass-specific activity of atomically dispersed catalysts for various processes, such as oxygen evolution reactions (OER), CO2 reduction, and biomass conversion, etc.