Surface conductance analysis of X-MoS₂ (X = Fe, Co, Ni) prepared on graphite felt as bifunctional catalysts for the hydrogen/oxidation evolution reactions

The surface admittances calculated from electrochemical impedance spectra are used to analyze the surface states of X-MoS₂ (X=Fe, Co, Ni) prepared on graphite felt. Because of the semiconducting properties of Fe-MoS₂ at the electrolyte-semiconductor interface, the bifunctional catalytic properties in the hydrogen/oxidation evolution reactions (HER/OER) are enhanced as a result of better surface adsorption/desorption and slow-changing surface conductance. The surface morphology and electric field between the semiconductor and electrolyte are important parameters affecting the surface properties in HER/OER.