Nickel-borate/reduced graphene oxide nanohybrid: a robust and efficient electrocatalyst for oxygen evolution reaction in alkaline and near neutral media

Designing highly active electrocatalysts with cost-effective transition metals for oxygen evolution reaction (OER) is of vital significance for multifarious energy conversion and storage devices. Herein, a facile in situ co-reduction method was applied for the preparation of nickel-borate nanoparticle on reduced graphene oxide (Ni−Bi/RGO) with high surface active sites exposure yield and reinforced electron transfer ability. Such Ni−Bi/RGO nanohybrid shows high catalytic activity with overpotential of 329 mV to drive a geometrical current density of 10 mA cm−2and Tafel slop of 79 mV dec−1in 1 m KOH. Moreover, this Ni−Bi/RGO nanohybrid also displays excellent performance under near neutral condition, with a low onset potential of 352 mV and Tafel slop of 176 mV dec−1in 0.1 m potassium borate (KBi, pH 9.2), better than most of Ni-based OER catalysts. Our research has paved a facile path for the development of highly active electrocatalysts.