Combinatorial modulation to augment the all-round HER activity of a Ru–CrN catalyst

Abstract

The proliferation of green technologies to combat the energy crisis has fostered the demand for efficient electrocatalysts towards the hydrogen evolution reaction (HER). It is a challenge to realize electrocatalysts with high activity and stability. Herein, we report a combinatorial design strategy by coupling Ru and CrN to boost the HER performance and durability, surpassing pristine Ru/NC, CrN/NC, and even commercial Pt/C. An in situ Ru–CrN decoration over N-doped carbon (Ru–CrN/NC) is achieved via one-step pyrolysis. CrN induces an electronic modulation in the hybrid that allows facile electron transfer to improve the HER activity. A drastic drop in the η₁₀ for Ru–CrN/NC to 7 and 2 times relative to CrN/NC and Ru/NC, respectively, is observed in alkaline media. Similar observations have been made in acidic media as well. Ru–CrN/NC shows high durability in both the reaction media after 24 h of operation, outperforming commercial Pt/C along with superior mass activity. The activity is mainly controlled by Ru and enhanced further due to the coupling with CrN, and the stability is due to the presence of CrN that inhibits the agglomeration of Ru. Density functional theory (DFT) calculations are done to explore the role of Ru and CrN components in the heterostructure, active sites for intermediate adsorption, revealing that the electronic modulation in the Ru–CrN system enhances the HER compared to Ru/NC.