Solid redox equilibrium via d-band centers regulation in the MoS₂/Ni₃S₂ heterojunction for efficient selective oxidation of 5-hydroxymethylfurfural

The 5-hydroxymethylfurfural electrocatalytic oxidation reaction (HMFOR), in coupling with the hydrogen evolution reaction (HER), can replace the kinetically slow anodic oxygen evolution reaction (OER) to produce high value oxides and hydrogen. However, the commonly employed Ni-based electrocatalyst exhibits an unsatisfied performance due to the existence of OER. Here, we design and synthesize the Ni₃S₂/MoS₂/NiMoO₄ catalyst for efficient and stable HMFOR reaction. Through the in situ Raman spectroscopy, we demonstrate that the Ni^III–OOH formed during the surface reconstruction process is the real reactive species for HMFOR. Moreover, the density functional theory results show that the upward shift of d-band centers in the reconstructed NiOOH/MoS₂ is beneficial for the HMF adsorption and guarantees the smooth progression of redox equilibrium reactions. As a result, the prepared electrocatalyst shows a good HMFOR electrocatalytic performance in terms of selectivity (99.2%), conversion (96.7%), and Faraday efficiency (96.5%).