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

Abstract

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.

Novel Thermotolerant and Flexible Polyimide Aerogel Separator Achieving Advanced Lithium‐Ion Batteries

“…As a result, to explain the high stability of the PIA separator at the molecular level, the bond dissociation energies in the polyimide molecule was determined by DFT calculations using the software Gaussian 16. [35,36] The bond dissociation energy was obtained by the cleavage reaction: [37] ′…”

Recent Progress in Graphene-Based Electrocatalysts for Hydrogen Evolution Reaction

“…The ReSe 2 @rGO electrocatalyst which has active sites exposed in the vertical direction of ReSe 2 nanosheets exhibited an overpotential of 145.3 mV and Tafel slope of 40.7 mV/dec at a current density of 10 mA/cm 2 . Hu et al [ 87 ] investigated the relationship between the overpotential required for graphene-covered HER electrocatalysts and the proton penetration current in order to understand what factors influence graphene-covered HER catalysts. The results show that the extent of proton penetration decreases as the number of layers of graphene-covered HER catalysts increases, and that the capability of protons to penetrate graphene determines the HER activity of graphene-covered non-precious metal catalysts.…”

Recent advances in MoS2-based materials for electrocatalysis

“…10 The electrochemical hydrogen evolution reaction, which converts water into high-purity H 2 , is a viable, efficient, and environmentally-friendly way to mitigate severe energy shortages and greenhouse gas emissions. 11–14 Similar to H 2 , ammonia (NH 3 ), with a high energy density, is a potential carbon-free transportation fuel. 15 It is also a crucial feedstock for fertilizers and has become the second highest produced chemical in the world.…”