Architecting Ni 3 Se 4 ‐NiSe 2 ‐Co 3 O 4 Triple‐Interface Heterostructure on MXene Nanosheets for Boosting Water Splitting by Electronic Modulation and Interface Effects

Abstract Strategically engineering electrocatalysts with optimized interfacial electronic architectures and accelerated reaction dynamics is pivotal for augmenting hydrogen generation via alkaline water electrolysis on an industrial scale. Herein, a novel triple‐interface heterostructure Ni 3 Se 4 ‐NiSe 2 ‐Co 3 O 4 nanoarrays are designed anchored on Ti 3 C 2 T x MXene (Ni 3 Se 4 ‐NiSe 2 ‐Co 3 O 4 /MXene) with significant work function difference (ΔΦ) as bifunctional electrocatalysts for water electrolysis. Theoretical calculations combined with experiments uncover the pivotal role of the interface‐induced electric field in steering charge redistribution, which in turn modulates the adsorption and desorption kinetics of reaction intermediates. Furthermore, the synergistic interaction between Ni 3 Se 4 ‐NiSe 2 ‐Co 3 O 4 and Ti 3 C 2 T x MXene nanosheets endows the hybrids with a large electrochemical surface area, abundantly active sites, and high conductivity. Thus, Ni 3 Se 4 ‐NiSe 2 ‐Co 3 O 4 /MXene manifests exceptional catalytic prowess for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In addition, the Ni 3 Se 4 ‐NiSe 2 ‐Co 3 O 4 /MXene electrocatalyst in the water electrolyzer delivers excellent performance and maintains commendable stability beyond 100 h of electrocatalytic operation.