Plasma-induced vacancy defects of Ru-doped CoFe layered double hydroxide for superior oxygen evolution activity

CoFe layered double hydroxide (CoFe LDH) can serve as a cost-effective and active electrocatalyst for oxygen evolution reaction (OER). Unfortunately, it still faces the challenges of low electrical conductivity, stability and limited active sites to achieve the threshold current density with low overpotential. In this study, the strategy of Ru doped together with air plasma treatment was proposed to improve the OER performances of CoFe LDH. The doping of Ru and air plasma process could induce electronic interaction and the oxygen defects to regulate the electronic structure. Significantly, the air plasma treated Ru doped CoFe LDH (P-Ru-CoFe LDH) catalyst achieved superior catalytic properties to the CoFe LDH and RuO ₂ benchmarks, which was demonstrated by a relatively smaller overpotential of 275 mV at 10 mA cm ⁻² and a lower Tafel slope of 107 mV dec ⁻¹ for OER. In addition, it also maintained an excellent stability in long-term chronoamperometry test. In general, P-Ru-CoFe LDH catalyst could boost the OER performance through intrinsic electronic structure adjustment with Ru doped and air plasma process. These findings provide an effective pathway to design/develop OER electrocatalysts with high performances by internal electron coupling effects.