Modulation of Charge Redistribution in Heterogeneous NiO‐Ni3Se4 Nanosheet Arrays for Advanced Water Electrolysis

Abstract Developing highly effective electrocatalysts capable of bifunctionally facilitating hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is paramount for advancing water electrolysis. Herein, the authors report heterogeneous NiO‐Ni 3 Se 4 nanosheet arrays grown on Ti 3 C 2 T x MXene (NiO‐Ni 3 Se 4 /MXene) with asymmetrical charge distribution as bifunctional electrocatalysts to enhance the electrocatalytic performance for overall water splitting. Impressively, the meticulously engineered NiO‐Ni 3 Se 4 /MXene exhibits remarkable catalytic activities for the HER and the OER with low overpotentials of 50 mV and 260 mV at 10 mA cm −2 , respectively. Moreover, the electrolyzer equipped with NiO‐Ni 3 Se 4 /MXene as both the cathode and anode demonstrates outstanding performance, reaching 10 mA cm −2 at a low cell voltage of 1.54 V and maintaining exceptional long‐term durability for over 50 h. The combination of theoretical calculations and experiments unveils the charge transfer induced at heterointerfaces in the NiO‐Ni 3 Se 4 heterogeneous, leading to asymmetrical charge distributions, which modulate the adsorption/desorption of the reaction intermediates and enhance the reaction kinetics. This study presents a promising approach for rationalizing heterogeneous electrocatalysts with exceptional performance.