Exploring cost-effective and highly-active oxygen evolution reaction (OER) electrocatalysts is a pressing task to propel water electrolysis for green hydrogen production. Herein, we constructed a class of Fe-doped and S-enriched Ni₃S₂ nanowires electrocatalysts for optimizing the target intermediates adsorption to decrease the OER overpotentials at various current densities. The optimal Ni₃S₂-1.4%Fe electrocatalyst possesses the most active sites and exhibits an ultralow overpotential of 190 mV at 10 mA cm⁻² with an excellent stability of > 60 h, exceeding the majority of recently-reported Ni₃S₂-based electrocatalysts. The trivalence Fe-doping not only reduces the electron density of the Ni center, but also enables the sulfur enrichment on the Ni₃S₂ surface, which greatly improves the intrinsic activity and the number of target intermediates (^*OOH). A novel methanol-assisted electrochemical evaluation further reveals that the Ni₃S₂-1.4%Fe electrocatalyst demonstrates a weaker binding ability to ^*OH with the rapid generation of ^*OOH species, and thus gives a lower apparent activation energy compared with the surface sulfur reduced ones. This work provides a new perspective for regulating the adsorption of intermediates through doping strategy.

The low specific capacity and sluggish electrochemical reaction kinetics greatly block the development of sodium-ion batteries (SIBs). New high-performance electrode materials will enhance development and are urgently required for SIBs. Herein, we report the preparation of supersaturated bridge-sulfur and vanadium co-doped MoS₂ nanosheet arrays on carbon cloth (denoted as V-MoS_2+x/CC). The bridge-sulfur in MoS₂ has been created as a new active site for greater Na⁺ storage. The vanadium doping increases the density of carriers and facilitates accelerated electron transfer. The synergistic dual-doping effects endow the V-MoS_2+x/CC anodes with high sodium storage performance. The optimized V-MoS_2.49/CC gives superhigh capacities of 370 and 214 mAh·g^-1 at 0.1 and 10 A·g^-1 within 0.4-3.0 V, respectively. After cycling 3,000 times at 2 A·g^-1, almost 83% of the reversible capacity is maintained. The findings indicate that the electrochemical performances of metal sulfides can be further improved by edge-engineering and lattice-doping co-modification concept.