Rationally Construction of Mn‐Doped RuO2 Nanofibers for High‐Activity and Stable Alkaline Ampere‐Level Current Density Overall Water Splitting

Abstract

AbstractNowadays, highly active and stable alkaline bifunctional electrocatalysts toward water electrolysis that can work at high current density (≥1000 mA cm−2) are urgently needed. Herein, Mn‐doped RuO2 (MnxRu1‐xO2) nanofibers (NFs) are constructed to achieve this object, presenting wonderful hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances with the overpotentials of only 269 and 461 mV at 1 A cm−2 in 1 m KOH solution, and remarkably stability under industrial demand with 1 A cm−2, significantly better than the benchmark Pt/C and commercial RuO2 electrocatalysts, respectively. More importantly, the assembled Mn0.05Ru0.95O2 NFs||Mn0.05Ru0.95O2 NFs electrolyzer toward overall water splitting reaches the current density of 10 mA cm−2 with a cell voltage of 1.52 V and also delivers an outstanding stability over 150 h of continuous operation, far surpassing commercial Pt/C||commercial RuO2, RuO2 NFs||RuO2 NFs and most previously reported exceptional electrolyzers. Theoretical calculations indicate that Mn‐doping into RuO2 can significantly optimize the electronic structure and weaken the strength of O─H bond to achieve the near‐zero hydrogen adsorption free energy (ΔGH*) value for HER, and can also effectively weaken the adsorption strength of intermediate O* at the relevant sites, achieving the higher OER catalytic activity, since the overlapping center of p‐d orbitals is closer to the Fermi level.