PNNL

Abstract

Alkaline hydrogen evolution reaction (A-HER) holds great promise for clean hydrogen fuel generation but its practical utilization is severely hindered by the sluggish kinetics for water dissociation in alkaline solutions. Traditional ways to improve the electrochemical kinetics for the A-HER catalysts have been focusing on surface modification, which still can not meet the demanding requirements for practical water electrolysis because of the catalyst surface deactivation. Herein, we report an interior modification strategy to significantly boost A-HER performance. Specifically, a trace amount of Pt was doped in the interior Co2P (Pt-Co2P) in order to introduce stronger dopant-host interaction than the surface-modified catalyst. Consequently, the local chemical state and electronic structure of the catalysts were adjusted by regulating energy levels to the Fermi level, beneficial for improving electron mobility and reducing the energy barriers for hydrogen adsorption and H-H bond formation. As a proof-of-concept, the interior-modified Pt-Co2P shows reduced onset potential at near-zero volt for A-HER, low overpotentials of 2 mV and 58 mV to achieve 10 and 100 mA cm-2, and excellent durability for long-term utilization. The interior-modified Pt-Co2P delivers superior A-HER performance to Pt/C and the state-of-the-art electrocatalysts. This work will open a new avenue for A-HER catalyst design.