Catalytic synergism in heterostructural Ta-doped Mo–Ni–S nanospheres: an efficient bifunctional catalyst for water splitting

Abstract

Designing suitable and efficient electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for sustainable hydrogen production. To date, extensive studies have focused on transition metal chalcogenides (TMSs) due to their unique electronic structure and strong ability to be modified. Herein, we reported a Ta-doped MoS₂/NiS catalyst supported on NF with a stable hierarchical nanosphere structure (Ta-MNS). The synergy between the MoS₂ and NiS phases in the same plane enhanced the mechanical strength and exposed more active sites, while Ta⁵⁺ was applied to adjust the electronic structure, resulting in a well-dispersed and flexible morphology. Moreover, the formation of the –S–Ta⁵⁺–S– bridge was proposed as a significant factor in enhancing the link between components at the active phase and further promoting electron transfer. As a result, for HER, the synthesized Ta-MNS required overpotentials of only 35 and 127 mV at current densities of 10 and 100 mA cm⁻², respectively. Furthermore, it demonstrated outstanding performance for OER and excellent stability, maintaining stable operation for more than 80 h. This paves a new avenue for the design of novel catalysts for water splitting.