Synergistic coupling of reduced graphene oxide with Ni0.85Se for highly active bifunctional electrocatalyst for water splitting

Abstract

Electrochemical water splitting can provide eco-friendly fuel. Nevertheless, this method requires efficient bifunctional electrocatalysts. In this study, a bifunctional electrocatalyst was synthesized by coating Ni0.85Se and hydrothermally-reduced graphene oxide on nickel foam (NF) using two-step electrodeposition. Moreover, graphene oxide was reduced through hydrothermal means prior to the pulse reverse electrodeposition. As confirmed by FT-IR, hydrothermally and electrochemically reduced graphene oxide on NF (HERGO) reveals a higher reduction degree in comparison to electrochemically-reduced graphene oxide on NF (ERGO). Ni0.85Se covered HERGO through the on-off cathodic pulse electrodeposition. Therefore, excellent electrocatalytic activity was obtained using the synergetic effect of RGO and Ni0.85Se. The ECSA values of 431 and 3500 cm2 were attained through coating HERGO and Ni0.85Se/HERGO on bare NF, respectively. The Ni0.85Se/HERGO revealed Ƞ10 of 67 and 230 mV for HER and OER, respectively. For overall water splitting, the Ni0.85Se/HERGO ǁ Ni0.85Se/HERGO device requaired 1.533 V at 10 mA/cm2.