Coupling High-Entropy Core with Rh Shell for Efficient Ph-Universal Hydrogen Evolution

Abstract

Constructing high-entropy alloys (HEAs) with core-shell (CS) nanostructure is efficiency for enhancing catalytic activity. However, it is extremely challenging to incorporate the CS structure with HEAs. Herein, PtCoNiMoRh@Rh CS nanoparticles (PtCoNiMoRh@Rh) with ~5.7 nm for pH-universal hydrogen evolution reaction (HER) are reported for the first time. The PtCoNiMoRh@Rh just require 9.1, 24.9 and 17.1 mV to achieve -10 mA cm-2 in acid, neutral and alkaline electrolyte, and the corresponding mass activity are 5.8, 2.79 and 91.8 times higher than that of Rh/C. Comparing to PtCoNiMoRh nanoparticles, the PtCoNiMoRh@Rh exhibit excellent HER activity attributed to the multi-active sites in HEA, the high facet index (2 2 1) and (5 5 3), as well as the synergistic effect in Rh shell and HEA core. Theorical calculation exhibits that Rh-dyz, dx2, and dxz orbitals experience a negative shift with shell thickness increasing. The HEAs with CS structure would facilitate the rational design of high-performance HEAs catalysts.

Keywords: PtCoNiMoRh@Rh core-shell, High entropy catalysis, pH-universal hydrogen evolution, Multiple active sites