Mapping Hydrogen Evolution Activity Trends of Intermetallic Pt-Group Silicides

Finding out the catalysis trend is an important prerequisite for the development of advanced or untouched catalysts. Intermetallic silicides composed of interstitial Si and Pt-group metals (PGMs) are currently rarely reported as hydrogen evolution reaction (HER) catalysts due to the absence of accessibility and predictability. Herein, by theoretical calculations, we unveil the activity trend of PGM silicides and show that IrSi is the most efficient HER catalyst because of the appropriate d-band center and optimal adsorption behavior. Furthermore, we pioneer the use of the molten salt-assisted synthesis strategy to successfully synthesize a series of PGM silicides (IrSi, PtSi, Pd2Si, RhSi, and RuSix) under normal pressure and mild conditions by overcoming the slow diffusion of silicon (Si) and verify the generality of this strategy. Electrochemical evaluation demonstrates that IrSi indeed possesses excellent HER catalysis activity, outperforming the commercial Pt catalyst, with an ultralow overpotential of 24 mV to achieve 10 mA cm(-2) in acidic media, and the predicted activity trend is further fitted experimentally. This work provides a valuable prediction result for catalysis and a feasible general method for construction of PGM silicides.

Automated summary

This study unveils the catalytic activity trend of platinum-group metal silicides, with IrSi identified as the most efficient catalyst for the hydrogen evolution reaction (HER). Additionally, a molten salt-assisted synthesis strategy is successfully employed to synthesize various PGM silicides, validating its generality. Electrochemical evaluation demonstrates that IrSi exhibits excellent HER catalysis activity, surpassing commercial platinum catalysts.