Tuning interfacial microenvironment of Ni(OH)2/GO by lanthanum doping for efficient photoelectrocatalytic oxidation of methanol

Nickel-based catalysts are attractive for methanol oxidation owing to their structural tunability and intrinsic activity for C–H bond activation. However, their limited ability to capture OH – at the reaction interface results in reduced energy-conversion efficiency. In this work, we demonstrate that La-Ni(OH) 2 /graphene oxide (GO) delivers a multilevel synergistic optimization that markedly enhances photoelectrochemical methanol oxidation. The random doping of La disturbs the periodicity of Ni–O lattice, which promotes surface reconstruction and the enrichment of OH – at the electrified interface. Notably, La doping-induced oxygen vacancies act as charge-trapping sites, promoting the separation of photogenerated electron-hole pairs. More photogenerated holes can reach the reaction interface and participate in oxidation, synergistically enhancing the photoelectrocatalytic efficiency. By optimizing the interfacial microenvironment, the La-Ni(OH) 2 /GO catalyst achieves a current density of 179.8 mA/cm 2 in alkaline medium and increases to 222.6 mA/cm 2 under illumination.