Construction of a S and Fe co-regulated metal Ni electrocatalyst for efficient alkaline overall water splitting

Rational design of bifunctional transition metal electrocatalysts with customary efficiency for water splitting is essential for yielding high-purity hydrogen, but remains challenging. Herein, we propose a non-metal atom S and oxyphilic transition metal atom Fe co-regulation strategy to optimize the alkaline hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance of metallic Ni (S-Fe-Ni). The S-Fe-Ni metal exhibits super activities with an ultralow overpotential of 25 mV and 200 mV at 10 mA cm(-2) and 89 mV and 235 mV at 100 mA cm(-2) for the HER and OER, respectively. When served as the cathode and anode, the S-Fe-Ni catalyst only needs 1.49 V to obtain 10 mA cm(-2) for water splitting. Further experimental results and theoretical calculations reveal that the S and Fe induced electronic redistribution optimizes water and hydrogen adsorption for enhanced HER and the in situ derived S doped NiFe hydroxyl oxide is associated with the enhanced OER. This work puts forward new insights into designing transition metal bifunctional catalysts for alkaline water splitting.