One Step Hydrothermal Synthesis of Ni-MoS2-RGO Bifunctional Electrocatalysts for HER and OER

Abstract

Pure MoS 2 and Ni-MoS 2 -RGO were prepared by a one-step hydrothermal approach. The result indicated that intensity of XRD diffraction peaks for MoS 2 increase slightly as with the increase of RGO content. Mesopores of the MoS 2 , Ni-MoS 2 /RGO-10 and Ni-MoS 2 /RGO-15 are mainly distributed in the pore diameter rage of 2-50 nm. The addition of RGO increase the layer numbers of MoS 2 in Ni-MoS 2 /RGO. Two Raman characteristic peaks at about 378 and 400 cm -1 according to A 1g and E 12g modes have been observed in the MoS 2 and Ni-MoS 2 /RGO. The eletrocatalytic test results show that the Ni-MoS 2 /RGO-5 has the lowest overpotentials of 349 mV at a current density of 10 mA cm -2 for OER and the Ni-MoS 2 /RGO-10 has the lowest overpotentials of 398 mV at a current density of 10 mA cm -2 for HER. Moderate Ni doping and RGO composites can effectively improve the intrinsic conductivity, the hydrogen adsorption free energy for HER, as well as providing more active sites for HER and OER.