Catalytic activity of graphene-covered non-noble metals governed by proton penetration in electrochemical hydrogen evolution reaction

Graphene-covering is a promising approach for achieving an acid-stable, non-noble-metal-catalysed hydrogen evolution reaction (HER). Optimization of the number of graphene-covering layers and the density of defects generated by chemical doping is crucial for achieving a balance between corrosion resistance and catalytic activity. Here, we investigate the influence of charge transfer and proton penetration through the graphene layers on the HER mechanisms of the non-noble metals Ni and Cu in an acidic electrolyte. We find that increasing the number of graphene-covering layers significantly alters the HER performances of Ni and Cu. The proton penetration explored through electrochemical experiments and simulations reveals that the HER activity of the graphene-covered catalysts is governed by the degree of proton penetration, as determined by the number of graphene-covering layers. Graphene-covering technology provides a promising approach for achieving a non-noble-metal-catalyst with corrosion protection and catalytic activity under acidic media. Here, the authors unveil that the electrochemical hydrogen evolution mechanism is governed by the proton penetration phenomenon.

Automated summary

The study reveals that increasing the number of graphene-covering layers significantly alters the hydrogen evolution reaction performances of nickel and copper, while graphene-covering technology provides a promising approach to achieve a non-noble-metal catalyst with corrosion protection and catalytic activity under acidic media.