Synergistic effect of V and Fe in Ni/Fe/V ternary layered double hydroxides for efficient and durable oxygen evolution reaction

High-performance and stable electrocatalysts are vital for the oxygen evolution reaction (OER). Herein, via a one-pot hydrothermal method, Ni/Fe/V ternary layered double hydroxides (NiFeV-LDH) derived from Ni foam are fabricated to work as highly active and durable electrocatalysts for OER. By changing the feeding ratio of Fe and V salts, the prepared ternary hydroxides were optimized. At an Fe:V ratio of 0.5:0.5, NiFeV-LDH exhibits outstanding OER activity superior to that of the binary hydroxides, requiring overpotentials of 269 and 274 mV at 50 mA(.)cm(-2) in the linear sweep voltammetry and sampled current voltammetry measurements, respectively. Importantly, NiFeV-LDH shows extraordinary long-term stability (not greater than or equal to 75 h) at an extremely high current density of 200 mA(.)cm(-2). In contrast, the binary hydroxides present quick decay at 200 mA(.)cm(-2) or even reduced current densities (150 and 100 mA(.)cm(-2)). The outstanding OER performance of NiFeV-LDH benefits from the synergistic effect of V and Fe while doping the third metal into bimetallic hydroxide layers: (a) Fe plays a crucial role as the active site; (b) electron-withdrawing V stabilizes the high valence state of Fe, thus accelerating the OER process; (c) V further offers great stabilization for the formed intermediate of FeOOH, thus achieving superior durability.