Rationally Construction of Mn-Doped RuO 2 Nanofibers for High-Activity and Stable Alkaline Ampere-Level Current Density Overall Water Splitting.

Nowadays, 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 RuO 2 (Mn x Ru 1-x O 2 ) 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 RuO 2 electrocatalysts, respectively. More importantly, the assembled Mn 0.05 Ru 0.95 O 2 NFs||Mn 0.05 Ru 0.95 O 2 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 RuO 2 , RuO 2 NFs||RuO 2 NFs and most previously reported exceptional electrolyzers. Theoretical calculations indicate that Mn-doping into RuO 2 can significantly optimize the electronic structure and weaken the strength of O─H bond to achieve the near-zero hydrogen adsorption free energy (ΔG H* ) 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.