Low-coordination atoms (LCAs) have been proven to play a critical role in boosting electrocatalysis. However, for enhancing catalytic activity, suitably engineering the LCAs in catalysts through rational design remains a challenge. Herein, we demonstrated self-supporting NiO/Co 3 O 4 hybrids for advanced oxygen evolution reaction (OER) performance. Contributed to an abundance of heterointerfaces and increased oxygen vacancies at the interfaces, the numerous LCAs were generated in NiO/Co 3 O 4 . Consequently, the NiO/Co 3 O 4 heterostructures exhibited an overpotential of only 262 mV at 10 mA cm −2 and a low Tafel slope of 58 mV dec −1 . By employing density functional theory calculations, it was determined that the d electrons were effectively regulated. Moreover, the d-band centers of Co near the interface in NiO/Co 3 O 4 were far from the Fermi level, thereby confirming the reduction of the unfavorable strong adsorption to oxo intermediates during the OER process. This study provides an effective approach for the rational construction of hybrid interfaces.

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Rational reconstruction of oxygen evolution reaction (OER) pre-catalysts and performance index of OER catalysts are crucial but still challenging for universal water electrolysis. Herein, we develop a double-cation etching strategy to tailor the electronic structure of NiMoO4, where the prepared NiMoO4 nanorods etched by H2O2 reconstruct their surface with abundant cation deficiencies and lattice distortion. Calculation results reveal that the double cation deficiencies can make the upshift of d-band center for Ni atoms and the active sites with better oxygen adsorption capacity. As a result, the optimized sample (NMO-30M) possesses an overpotential of 260 mV at 10 mA cm−2 and excellent long-term durability of 162 h. Importantly, in situ Raman test reveals the rapid formation of high-oxidation-state transition metal hydroxide species, which can further help to improve the catalytic activity of NiMoO4 in OER. This work highlights the influence of surface remodification and shed some light on activating catalysts.