CuCo2O4 nanoparticles on nitrogenated graphene as highly efficient oxygen evolution catalyst

• CuCo2O4 nanoparticles of size 4.0 nm were facilely synthesised on NrGO sheets.
• CuCo2O4/NrGO hybrid was explored as OER catalyst for the first time.
• CuCo2O4/NrGO shows high activity than any of the Cu–Co catalysts reported.
• The hybrid has shown good stability in alkaline media.
• High activity is due to presence of divalent copper ions at octahedral sites.

Highly active, durable and cost-effective electrocatalysts for oxygen evolution reaction play a key role on developing energy-conversion technologies. Here, we report a composite material consisting of CuCo2O4 nanoparticles anchored on nitrogenated reduced graphene oxide (CuCo2O4/NrGO) as a highly efficient oxygen evolution electrocatalyst in both alkaline and neutral solutions for the first time. In 1 M KOH, 0.1 M KOH and 0.1 M PBS, CuCo2O4/NrGO catalyst exhibited a current density of 10 mA cm−2 at a small overpotential of 0.36 V, 0.41 V and 1.15 V respectively, which are better than those of RuO2 and IrO2 catalysts. The CuCo2O4/NrGO exhibited good stability under strong alkaline conditions. The enhanced OER performance of CuCo2O4/NrGO is attributed to the presence of Cu2+ ions at the octahedral sites, reduction in the size of the CuCo2O4 nanoparticles as measured by the TEM, enhancement of electrochemically active surface area (ECSA), and synergetic effect between CuCo2O4 nanoparticles and NrGO sheets. This cost effective and highly efficient catalyst can possibly replace the expensive catalysts such as RuO2 and IrO2.

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