Well-ordered single-atomic cobalt-1T-MoS₂/C superlattice heterostructure toward durable overall water splitting

Van der Waals superlattice heterostructure with different two-dimensional (2D) nanosheets provides a promising way to exploit the intrinsic properties of both 2D components. However, developing efficient methods for precisely constructing ordered/controlled layer sequence superlattice heterostructures has always been challenging. Here, we report a facile strategy for the preparation of single-atomic cobalt anchored 1T-MoS₂/carbon (Co-1T-MoS₂/C) heterostructure with a well-ordered superlattice of alternating Co-1T-MoS₂ and C nanosheets at a molecular level. The coordination of Co atoms on the 1T-MoS₂ matrix and its effect on the phase transformation of MoS₂ has been systematically investigated. Importantly, the Co atoms can efficiently improve the metastable 1T phase stability of MoS₂. As a proof-of-concept application, the obtained Co-1T-MoS₂/C is employed as an electrocatalyst for overall water splitting in alkaline conditions. The rapid interfacial charge transfer and abundant active catalytic sites, coupled with the contribution of the single-atomic Co sites enable the Co-1T-MoS₂/C superlattice heterostructure to exhibit excellent performance. The assembled Pt/C||Co-1T-MoS₂/C cell needs only 1.57 V to reach the current density of 10 mA/cm². Our research strategy provides a feasible path for the design of 2D-2D van der Waals superlattice heterostructures and further broadens their applications.