“…As shown Figure S5a, the adsorption−desorption curve of FeNiCoO x /CoO x /CP is a type-IV isotherm with a hysteresis loop at 0.4 of P/P 0 , indicating its mesoporous structure. 42 The pore size distribution determined by the Barrett−Joyner−Halenda (BJH) model exhibits the mesopore feature of the as-synthesized FeNiCoO x /CoO x ranging from 2 to 50 nm (Figure S5b), effectively promoting the mass transport. 43,44 The Brunauer−Emmett−Teller (BET) surface area of FeNiCoO x /CoO x is 13.868 m 2 g −1 , much higher than that of CoO x /CP (5.323 m 2 g −1 ) (Figure S5c and S5d), suggesting more exposed active sites after the deposition of FeNiCoO x .…”