Enhanced electron penetration triggering interfacial charge redistribution in N-doped graphene-wrapped NiGd nanoparticles for coupling methanol electroreforming to H2 production

Abstract

Rational construction of advanced electrocatalysts that can realize coupling of the hydrogen evolution reaction (HER) with electrooxidation of organic compounds, rather than the sluggish oxygen evolution reaction, will make the catalytic efficiency of electrolytic hydrogen production more efficient. Herein, we report a bifunctional chainmail catalyst composed of NiGd nanoparticles wrapped by N-doped graphene shells (NiGd@N–C) for both the HER and methanol oxidation reaction (MOR). Benefiting from the unique architecture, the NiGd@N–C catalyst exhibits excellent HER activity under alkaline conditions (η₁₀ = 45 mV), and also performed with high activity for selective methanol oxidation to formate. Theoretical analysis verifies that introducing the rare earth Gd element could enhance electron penetration from the NiGd core to the N–C shell, which was responsible for enhanced HER and MOR performance. Impressively, the methanol–water co-electrolysis system based on bifunctional NiGd@N–C catalysts only needs 1.34 V of cell voltage to reach 10 mA cm⁻² for co-electrosynthesis of hydrogen and formate.