Exploiting Lattice Carbon-Induced Modulation Effect in Nickel towards Efficient Alkaline Hydrogen Oxidation

Doping with non-metallic heteroatom is an effective approach to tailor the electronic structure of Ni for enhancing its alkaline hydrogen oxidation reaction (HOR) catalytic performance. However, the modulation of HOR activity of Ni by lattice carbon (LC) atoms has rarely been reported, especially to reveal the rule between the doping effect and activity caused by the content of LC atoms. Here, hydrogen is proposed as a scavenger for LC atoms in the pyrolytic reduction process to finely control the content of LC atoms in Ni. With the removal of LC atoms in Ni lattice, the electronic structure changes from Ni₃C-like electronic structure to quasi-Ni structure. Furthermore, a volcanic relationship between the LC content and HOR activity of Ni is established for the first time. The C_less-Ni (LC_0.44-Ni) with optimized LC content shows the best activity owing to the weakened hydrogen binding energy (HBE) and optimal hydroxyl binding energy (OHBE). This work provides an inspiration for the design of high-performance catalysts by tailoring the electronic structure of the metal via LC atoms doping.