Manipulating d‐Band Center of Ru Sites in Branched RuO2 Nanofibers Enables Significantly Enhanced Alkaline Overall Water Splitting Performance

Abstract Although ruthenium dioxide (RuO 2 ) is an efficacious oxygen evolution reaction (OER) catalyst in acidic media, its performance in alkaline conditions is subpar and it is also ineffective for hydrogen evolution reaction (HER) in common electrolytes. Here, an effective phosphorus (P)‐doping strategy is introduced to manipulate the d ‐band center of ruthenium (Ru) sites, attenuating the adsorption energy of HER intermediates and lowering the energy barrier in OER, thereby significantly accelerating both HER and OER performance. The representative 10%P‐RuO 2 nanofibers (NFs) catalyst presents an ultralow overpotential of 177.9 mV at 1 A cm −2 and long‐term stability of 300 h in 1 m KOH toward HER, greatly exceeding those of benchmark platinum (Pt)/C catalyst. Moreover, the 10%P‐RuO 2 NFs catalyst exhibits an exceptional OER performance with a low overpotential of 250 mV at 10 mA cm −2 (η 10 ) and desirable stability of 150 h at 1 A cm −2 , which is far better than commercial RuO 2 and many other typical previously reported OER catalysts. Additionally, an overall water electrolytic cell using 10%P‐RuO 2 NFs as both anode and cathode necessitates a working voltage of 1.52 V (η 10 ) and demonstrates long‐term stability over 100 h at 1 A cm −2 , outperforming many typical water electrolysis cells.