Inter-atomic electronic interactions enabled by a Rh single atoms/CuCo₂S₄@MoS₂ core-shell heterostructure for high-efficiency solar-assisted water splitting

In this work, we developed an electrocatalyst of Rh single atom-confined CuCo₂S₄@MoS₂ core-shell heterostructure (Rh SAs/CuCo₂S₄@MoS₂) for the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). Interatomic electronic interaction between Rh single atoms and the CuCo₂S₄@MoS₂ heterostructure allows the improvement of the intrinsic catalytic behavior of each active site. In addition, the Rh SAs/CuCo₂S₄@MoS₂ catalyst combines all advantages of the Rh single atom centers, the uniform core-shell structure of CuCo₂S₄@MoS₂ nanorods, and the open three-dimensional configuration of nickel foam, which significantly enhance the electroactive surface area to expose more active sites, accompanied by excellent capability in charge and mass transportations. As a result, to achieve a current density of 10 mA cm⁻², the device using Rh SAs/CuCo₂S₄@MoS_2(+,−) requires a cell voltage of 1.589 V, along with a high STH conversion efficiency of 19.12%. The high catalytic activities for all the HER, OER, and solar-assisted overall water splitting processes evidenced that Rh SAs/CuCo₂S₄@MoS₂ is a potential electrocatalyst for green hydrogen production.