Synthesis and properties of nickel/graphene electrodes for hydrogen generation

ABSTRACT The use of nanomaterials, such graphene oxide (GO), as blocks for the synthesis of hybrid materials has been extensively studied in recent years. In this paper a simple and reproducible method for the synthesis of hybrid nickel/graphene electrodes is presented. This method involves the modification of a conventional electroplating nickel bath by incorporating graphene oxide flakes, so the synthesis can be industrially scalable. The synthesized catalyst was structurally and electrochemically characterized. The XRD studies show no appreciable change in the lattice parameter, but a decrease is observed in the relationship between (200)/(111) planes related to an increase in catalyst stability. Raman spectra show the characteristic reduced GO bands on the catalyst matrix. Also, the formation of nickel hydrides in the nickel/graphene catalyst is not observed, unlike the pure nickel electrode. The kinetics of hydrogen evolution reaction (HER) was studied in both, conventional nickel and nickel/graphene catalysts, finding changes in activity. The hybrid catalyst has a higher catalytic activity towards the HER and the presence of GO in the Ni matrix inhibits the nickel hydride formation with the consequent loss of catalytic activity.