The interstitial Ru dopant induces abundant Ni(Fe)Ru cooperative sites to promote ampere-level current density for overall water splitting

The well-designed Ru-NiFeP/NF electrode is constructed by ’quenching doped Ru-phosphorization’ strategy. Remarkably, the interstitial Ru dopants induce abundant Ni(Fe)Ru bonds with optimized electronic configuration, greatly stabilizing the presence of Ru and enhancing the reaction kinetics for HER and OER. As expected, the η1000 value of Ru-NiFeP/NF is merely 0.285 V for HER and 0.34V for OER, is 0.9 times that of Pt/C@NF in HER and 0.62 times that of RuO2@NF in OER, respectively. Benefit from the abundant Ni(Fe)Ru cooperative sites, the Ru-NiFeP/NF||Ru-NiFeP/NF electrolyzer only needs a voltage of 1.54 V to provide a current density of 1 A cm−2, which is much better than that of Pt/C@NF||RuO2@NF. [Display omitted] Directionally induced interstitial Ru dopant rather than ordinary substitutional doping is a challenge. Furthermore, DFT calculations revealed that compared with the substituted Ru dopants, the interstitial Ru dopants induce abundant Ni(Fe)Ru cooperative sites, greatly expediting the reaction kinetics for HER and OER. Inspired by these, the interstitial Ru-doped NiFeP/NF electrode is constructed by the ’quenching doped Ru-phosphorization’ strategy. Relevant physical characterizations confirmed that interstitial Ru dopants promote electron reset in the Ni(Fe)Ru synergistic sites, effectively avoiding metal atom dissolution and encouraging more Ni (Fe)OOH active species. As expected, the Ru-NiFeP/NF||Ru-NiFeP/NF electrolyzer only need as low as 1.54 V to yield a current density of 1 A cm−2. In summary, this work innovatively constructs the phosphide electrode with ampere-level current density from the perspective of regulating the doping position of Ru. This provides a new design idea for optimizing the Ru doping strategy.