Reduced graphene oxide supported nitrogen-doped porous carbon-coated NiFe alloy composite with excellent electrocatalytic activity for oxygen evolution reaction

Designing of cost-effective electrocatalysts for efficient oxygen evolution reaction (OER) is highly desired for the practical production of clean hydrogen energy. Herein, reduced graphene oxide (RGO) supported N-doped porous carbon-coated NiFe alloy composite (NiFe@NC/RGO) was synthesized via a facile pyrolysis route. The introduction of RGO effectively protects the active NiFe component from agglomeration and largely promotes charge transfer. Meanwhile, the formation of porous N-doped carbon shell provides sufficient contact between active species and electrolyte, thus exposing plenty of accessible active sites. Specifically, the optimized NiFe@ NC/RGO composite shows superior electrocatalytic performance, delivering an overpotential as low as 223 mV at current density of 10 mA cm(-2), and a small Tafel slope of 48.7 mV dec(-1) in 1 M KOH solution, which outperforms commercial precious metal oxide catalysts such as RuO2 and a vast majority of electrocatalysts reported so far. Long-term cycling test demonstrates that the overpotential at current density of 10 mA cm(-2) has almost no change after 1000 cycles at a scan rate of 50 mV s(-1), indicating its quite good stability. The low-cost and high-performance electrocatalyst developed in this work shows great potential for practical hydrogen production from electrolysis of water.