Effect of MoS2 in doped-reduced graphene oxide composites. Enhanced electrocatalysis for HER

The hydrogen evolution reaction (HER) is a crucial electrochemical reaction for the desired hydrogen economy since it has the potential to provide pure hydrogen for fuel cells. With the aim to solve the principal catalytic and economic problems at the cathode electrode in which HER takes place, a series of two-dimensional (2D) com-posites with different modified-reduced graphene oxide (X-rGO) sheets and a few molybdenum disulfide (MoS2) flakes were obtained by a simple method. Main results indicate that the HER is strongly influenced by the nature and amount of the doping agent (S and/or N) in addition to the interaction with MoS2. Furthermore, differential electrochemical mass spectrometry (DEMS) precisely determines the onset potential and the rate determining step (RDS) for the HER at the 2D catalysts, which indicates similar reaction mechanism but diverse exchange current density that is influenced by the nature of the 2D material.