Precisely
tailoring the electronic structures of electrocatalysts
to achieve an optimum hydroxide binding energy (OHBE) is vital to
the alkaline hydrogen oxidation reaction (HOR). As a promising alternative
to the Pt-group metals, considerable efforts have been devoted to
exploring highly efficient Ni-based catalysts for alkaline HOR. However,
their performances still lack practical competitiveness. Herein, based
on insights from the molecular orbital theory and the Hammer–Nørskov
d-band model, we propose an ingenious surface oxygen insertion strategy
to precisely tailor the electronic structures of Ni electrocatalysts,
simultaneously increasing the degree of energy-level alignment between
the adsorbed hydroxide (*OH) states and surface Ni d-band and decreasing
the degree of anti-bonding filling, which leads to an optimal OHBE.
Through the pyrolysis procedure mediated by a metal–organic
framework at a low temperature under a reducing atmosphere, the obtained
oxygen-inserted two atomic-layer Ni shell-modified Ni metal core nanoparticle
(Ni@Oi-Ni) exhibits a remarkable alkaline HOR performance
with a record mass activity of 85.63 mA mg–1, which
is 40-fold higher than that of the freshly synthesized Ni catalyst.
Combining CO stripping experiments with ab initio calculations, we further reveal a linear relationship between the
OHBE and the content of inserted oxygen, which thus results in a volcano-type
correlation between the OH binding strength and alkaline HOR activity.
This work indicates that the oxygen insertion into the top-surface
layers is an efficient strategy to regulate the coordination environment
and electronic structure of Ni catalysts and identifies the dominate
role of OH binding strength in alkaline HOR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.