Constructing Sulfur Vacancy-Rich NiCo2S4@MoS2 Core@shell Heterostructure via Interface Engineering for Enhanced HER Electrocatalysis
Ziteng Song, Yuan Liu, Peng Yin, Jie Dai, Yingying Xu, Rongming Wang, Sibin Duan
Abstract
The rational design of heterointerfaces with optimized charge dynamics and defect engineering remains pivotal for developing advanced non-noble metal-based electrocatalysts for water splitting. A comparative study of NiCo2S4–MoS2 heterostructures was conducted to elucidate the impact of interfacial architecture and defect engineering on hydrogen evolution reaction (HER) performance. A core@shell NiCo2S4@MoS2 heterostructure was synthesized via a facile hydrothermal growth method, inducing lattice distortion and strong interfacial coupling, while supported NiCo2S4/MoS2 heterostructures were prepared by ultrasonic-assisted deposition. A detailed structural and spectroscopic characterization and theoretical calculation demonstrated that the core@shell configuration promotes charge redistribution across the NiCo2S4–MoS2 interface and generates abundant sulfur vacancies, thereby increasing the density of electroactive sites. Electrochemical measurements reveal that NiCo2S4@MoS2 markedly outperforms the supported heterostructure, single-component NiCo2S4, and MoS2 when serving as the HER catalyst in acid solution. These findings establish a dual-optimization strategy—combining interfacial design with vacancy modulation—that provides a generalizable paradigm for the deliberate design of high-efficiency non-noble metal-based electrocatalysts for water splitting reactions.