Design of single atom coupled nitrogen doped graphene/molybdenum sulfide interface significantly improves water splitting property

Developing efficient, clean, and robust electrochemical energy devices to tame the energy crisis and greenhouse effect is urgently required for environmental sustainability. We present a method enabling the design of atomically dispersed metals supported on Nitrogen-doped Graphene (NGr) and MoS₂ heterostructure through a facile synthesis technique, which enhances water-splitting performance. The cobalt atoms are anchored and exposed on the surface of the NGr/MoS₂ due to strong electron interaction and efficient chemical bond interaction. The atomic interface structure enhances the exposure of atomically dispersed Co, thereby increasing the number of active sites for oxygen/hydrogen reaction intermediates adsorption. Additionally, the strong Electronic Metal-Support Interactions (EMSIs) induce significant charge delocalization in Co atoms, leading to changes in bond energy and charge redistribution. The MoS₂ and NGr-Co Single-Atom Catalysts (SACs) heterostructures demonstrate promising catalytic performance, with a low Oxygen Evolution Reaction (OER) overpotential of 310 mV and Hydrogen Evolution Reaction (HER) overpotential of 200 mV at 10 mA cm⁻², along with remarkable stability. The catalysts retain their original structure with negligible activity loss even after 60 h. OER/HER investigations and Density Functional Theory (DFT) calculations reveal that the MoS₂/NGr-Co active moieties facilitate the rate-limiting release of OH* and lower H* energy barrier and enhance the OER/HER process compared to MoS₂-Co SACs and MoS₂. Additionally, the excellent water-splitting performance of these catalysts is attributed to the high affinity of Co-N₄ active sites for H₂ and O₂, supported by their unique anti-poisoning properties toward NGr. Therefore, the facile and scalable fabrication method, combined with relevant catalytic efficiency and robust stability, highlights the potential for practical applications.