Enabling energy-efficient benzyl alcohol oxidation with a NiO-Cr2O3 Mott–Schottky heterojunction

Heterostructure engineering via the construction of Mott–Schottky (M–S) interfaces is a powerful strategy for designing advanced electrocatalysts. This study designs and synthesizes a NiO-Cr 2 O 3 M–S heterojunction for the efficient benzyl alcohol oxidation reaction (BAOR), which achieves a current density of 100 mA cm −2 at a low potential of 1.46 V (vs. RHE). Spectroscopic characterizations and theoretical calculations confirm the formation of an M–S junction, where a significant work function difference drives spontaneous electron transfer from NiO to Cr 2 O 3 , establishing a strong built-in electric field at the interface. This interfacial charge rearrangement fundamentally reshapes the electronic environment of the Ni active sites, enhancing the initial adsorption of reactants and upshifting the Ni d-band center. Such electronic modulation optimizes the binding strength of key intermediates and ultimately lowers the energy barrier for the rate-determining step (*Ph-CH 2 O→*Ph-CHO). The practical utility of the NiO-Cr 2 O 3 is demonstrated in a hybrid water electrolyzer, where it enabled substantial energy savings for H 2 production and the generation of benzoic acid. This work provides a clear validation of M–S heterojunction engineering as a powerful design principle for creating next-generation catalysts that synergize energy-efficient processes with value-added chemical synthesis.