LAUSR

Perovskite oxides have been recognized as one of the most attractive oxygen evolution reaction (OER) catalysts because of their low cost, earth-abundance, and robust nature. Herein, one-dimensional porous LaFe1-xNixO3 perovskite oxide nanofibers (LFNO NFs) are fabricated with a feasible electrospinning route and its further post-calcination treatment. By tailoring atomic percent of Fe and Ni in the perovskite oxide, we determined that LaFe0.25Ni0.75O3 (LFNO-III) NFs afford the best OER activity among all the prepared perovskite oxides. Especially remarkable is that the further selenide-doped LaFe0.25Ni0.75O3 (LFNOSe-III) NFs exhibit outstanding OER activity with a low overpotential of 287 mV at 10 mA cm-2 and a small Tafel slope of 87 mV dec-1 in 1 M KOH solution, markedly exceeding that of the parent perovskite oxide and the commercial RuO2. It also delivers decent durability with no significantly degrade after 22 h stability test. In the meanwhile, density functional theory calculations are also conducted to justify the optimized adsorption features of *OH, *O, and *OOH intermediates, and unveil that the electrocatalytic active sites are the Ni atoms that adjacent to Fe in the Ni- and Se co-doped perovskite. This work provides an effective method for the development of highly-efficient perovskite oxide catalysts.