Carbon impurity-free, novel Mn,N co-doped porous Mo2C nanorods for an efficient and stable hydrogen evolution reaction

Abstract

Heteroatom doping is an effective way to modulate the electronic configuration and optimize the electroactivity over a series of electrocatalytic materials. Here we report novel kinds of Mn,N co-doped porous Mo₂C nanorods for the hydrogen evolution reaction (HER) in acidic solution, which are facilely fabricated based on Mn-modified MoO_x-amine precursors. The obtained porous, monocrystalline nanorods without carbon impurities could not only provide abundant catalytic sites, but also facilitate electrolyte penetration and hydrogen release. Furthermore, the fine-tuned electronic structure of Mo₂C nanorods with Mn,N dopants could produce more available active sites and reduce the hydrogen adsorption energy (ΔG_H*). As a result, the optimized Mn,N co-doped Mo₂C nanorods exhibit high HER activity with a low overpotential (η₁₀ = 163 mV), a small Tafel slope (66 mV dec⁻¹), and excellent long-term stability in acidic electrolyte. EPR and DFT calculations confirm that the high performance originates from new active sites (Mn site), a low charge-transfer resistance and an optimized adsorption–desorption behavior after Mn,N co-doping. This work may provide a new pathway to design and explore efficient non-noble metal water-splitting electrocatalysts via electronic engineering of their compositions and nanostructures.