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In promising transition metal sulfide catalysts, the extraordinary instability under air exposure and oxygen evolution reaction (OER) catalysis severely degrades their activity and stability in the electrochemical water splitting reaction, inhibiting their practical applications. Herein, guided by a theoretical mechanism study, it is disclosed that the adsorbing ability and electronic interaction for molecular oxygen will be significantly weakened in nickel disulfide (NiS 2 ) by constructing an electron-deficient distribution on Ni−S sites with N atom introduction, which efficiently inhibits the process of O 2 adsorption and electrophilic activation during oxidation, thus achieving air-stable capacity for NiS 2 . In addition, theoretical calculations further reveal that such an electronic redistribution will weaken the OH − adsorption on NiS 2 and thus inhibit the reconstruction process during the OER process. Inspired by this, NiS 2 nanosheets (NiS 2 NSs) are synthesized and N atoms are introduced to bridge with Ni and S, resulting in electron-deficient Ni and S sites in N atom-bridged NiS 2 NSs (N−NiS 2 NSs). As expected, only 28.1% of the NiS 2 phase is oxidized into sulfate nickel in N−NiS 2 NSs after one month of air exposure with only 13 mV overpotential degradation toward the OER, while for NiS 2 NSs, a fast and drastic phase transformation is undergone, resulting in 155 mV OER decline. For the OER process, the reconstruction from sulfides to (oxy)hydroxides is deservedly inhibited in such N−NiS 2 NSs, with an in situ constructed N−NiS 2 /NiOOH heterostructure as an OER active phase, which exhibits higher OER activity and stability compared to those of completely NiOOH-oxidized NiS 2 NSs. Rationalized by density functional theory (DFT) calculations, the N−NiS 2 /NiOOH heterostructure features a strong electron rearrangement at the interface, thus improving the chemisorption ability and conductivity compared to those of pristine NiOOH. Moreover, such a strategy of improving the air stability is also valid for other transition metal sulfides (TMS) (such as CoS 2 and FeS 2 ).

The Pt3Sn nanoparticles (NPs) enriched with Pt3Sn/SnO2 interfaces (Pt3Sn@u-SnO2/NG) were achieved through thermal treatment of Pt2Sn/NG in H2 atmosphere, followed by annealing under H2 and air conditions. The unique structure...