Identification of Co–O–Mo Active Centers on Co-Doped MoS2 Electrocatalyst

Strategies for harmonizing the construction of an active site and the building of electron transport for a hybrid MoS2 catalyst are crucial for its application in electrochemical reactions. In this work, an accurate and facile hydrothermal strategy was proposed to fabricate the active center of Co–O–Mo on a supported MoS2 catalyst by forming a CoMoSO phase on the edge of MoS2, yielding (Co–O)x-MoSy (x = 0, 0.3, 0.6, 1, 1.5, or 2.1). The results show that the electrochemical performances (hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical degradation) of the yielded MoS2-based catalysts were positively correlated with the Co–O bonds, verifying the significant role of Co–O–Mo as the active center. The fabricated (Co–O)-MoS0.9 presented an extremely low overpotential and Tafel slope in both HER and OER, and it also demonstrated excellent BPA removal in the electrochemical degradation reaction. As compared with the Co–Mo–S configuration, the configuration of Co–O–Mo not only serves as the active center but also provides a conducting channel to facilitate electron conductivity with more accessible charge transfer at the electrode/electrolyte interface, which is favorable for electrocatalytic reaction. This work offers a new perspective for the active mechanism of metallic-heteroatom-dopant electrocatalysts and further boosts research on the development of noble/non-noble hybrid electrocatalysts in the future.