Ni(OH)2/Ni/g-C3N4 composite: An efficient electrocatalyst for hydrogen evolution

Abstract The preparation of efficient catalysts in hydrogen evolution reaction (HER) is an urgent task at present. In this work, Ni(OH)2/Ni/g-C3N4 composite catalyst was prepared through liquid phase impregnation with in-situ reduction, which was used to compose the cathode with carbon paper (CP) for the microbial electrolysis cell (MEC). With the help of SEM, TEM, XRD, XPS and electrochemical analysis techniques, the structure, properties and electrocatalytic performance in hydrogen evolution of the Ni(OH)2/Ni/g-C3N4 composite were investigated. The results indicate that the Ni(OH)2/Ni/g-C3N4 catalyst exhibits excellent electrochemical activity for hydrogen evolution in the MEC. Using the Ni(OH)2/Ni/g-C3N4 catalyst, the current density reaches 100 A/cm2 at a small overpotential of 1881 mV, with a low charge transfer resistance of 10.86 Ω and a low Tafel slope of 44.3 mV/dec, which is much superior to pure g-C3N4 catalyst and CP, and even comparable to the Pt catalyst, suggesting that the Ni(OH)2/Ni/g-C3N4 composite can be a potential candidate of HER catalyst in MEC.