Tailoring hydrogen adsorption via charge transfer at bimetallic Cr0.48Ru0.52 alloy nanoparticles decorated on carbon nanofiber for enhanced hydrogen evolution catalysis

Abstract

Designing and synthesizing highly efficient and stable electrocatalysts for the hydrogen evolution reaction (HER) is crucial for the practical and large-scale application of hydrogen sources. Recent research has focused on tuning the electronic structure of electrocatalysts to achieve optimal HER activity, with particular emphasis on interfacial engineering to induce electron transfer and optimize HER kinetics. In this study, as part of research into heterointerface engineering, bimetallic Cr_0.48Ru_0.52 alloy nanoparticles decorated on carbon nanofibers (Cr_0.48Ru_0.52/CNFs) were fabricated through a simple electrospinning and post-calcination process to serve as an efficient alkaline HER catalyst. The Cr_0.48Ru_0.52/CNFs demonstrated exceptional electrocatalytic HER performance, with an overpotential of only 13 mV at −10 mA cm⁻² and a Tafel slope of 60.8 mV dec⁻¹, indicating high catalytic activity compared to commercial benchmark catalysts (i.e., Ru/C and Pt/C). First-principles density functional theory calculations support these results, revealing that Cr_0.48Ru_0.52 balances proton reduction (Volmer step) and H∗ desorption (Tafel/Heyrovsky step) processes during electrocatalysis, as evidenced by the near-zero hydrogen adsorption (ΔG_H∗) value (ca. −0.11 eV). Therefore, this study highlights that Cr_0.48Ru_0.52/CNFs, with noble Ru comprising only half of the total metal content, can promote optimal HER kinetics under alkaline condition.