High-entropy alloy nanocrystal assembled by nanosheets with d–d electron interaction for hydrogen evolution reaction†
Abstract
The development of efficient catalysts with superior performance for water splitting into hydrogen is urgently required in the catalysis community. Herein, for the first time, we report unique high-entropy alloy (HEA) catalysts– PtMoPdRhNi nanocrystals (NCs) with strong d–d electron interaction encapsulated with radial nanosheets. Through the exploration of the atomic ratio of PtMoPdRhNi, the obtained Pt28Mo6Pd28Rh27Ni15 NCs with the strongest d–d electron interaction display the highest alkaline hydrogen evolution reaction (HER) activity, with the overpotential as low as 9.7 mV at a current density of −10 mA cm−2. The superior HER performance mainly originated from the d–d electron interaction in constituent metals and multi-active sites with optimized energy barriers of HEAs. In situ surface-enhanced Raman spectroscopy (SERS) and theoretical calculations are combined to reveal the mechanism in both water dissociation and H* adsorption/desorption. This study not only elucidates the complex structural information and the catalytic mechanisms of multielement HEA systems in depth for further rational design of efficient catalysts but also highlights HEAs as sufficiently advanced catalysts and accelerates the research of HEAs in energy-related applications.