“Tip effect” of hexagram-like Co-doped MoC heterostructure for hydrogen evolution reaction

It is urgent to develop an efficient and durable transition metal based electrocatalyst to overcome the slow water dissociation kinetics of the alkaline hydrogen evolution reaction (HER). Thus, a novel hexagram-like porous N-doped Co/MoC Mott–Schottky electrocatalyst (Co/MoC@NC) derived from Zn/Co ZIF-L doped with phosphomolybdic acid hydrate (POM) was developed for alkaline HER. The abundant Mott–Schottky interfacial heterostructures provided sufficient active sites, which accelerated electron and mass transport. DFT calculations indicated that Co/MoC Mott–Schottky heterostructure accelerated water adsorption and dissociation. COMSOL simulations showed that the "tip effect" of hexagram-like structures provided a localized field with high electric charges. The resulting H+-rich tip surface promoted alkaline reaction kinetics to improve HER performance. The Co/MoC@NC catalyst exhibited an excellent HER performance with a low overpotential of 80.6 mV at a current density of −10 mA/cm2 in 1 M KOH.