Self-Supported Phosphorus-Doped Vertically Aligned Graphene Arrays Integrated with FeCoNiP Nanoparticles as Bifunctional Electrocatalysts for Water-Splitting Over a Wide pH Range

Self-supported non-noble metal based bifunctional electrocatalysts with high catalytic activity and long-term stability in a wide pH range are highly essential for the production of hydrogen and oxygen, remains a great challenge. Herein, a bifunctional electrocatalyst is synthesized via electroless plating of FeCoNiP nanoparticles on self-supported phosphorus-doped vertically aligned graphene arrays (FeCoNiP/P-VG). FeCoNiP/P-VG exhibits an exceptionally high catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in a wide pH range, with an overpotential of 81 and 141 mV for HER, and 240 and 409 mV for OER, in 1.0 M KOH and 0.5 M H 2 SO 4 respectively, at current density of 10 mA. It also performs quite low Tafel slope value of 40 mV·dec −1 for HER and 69 mV·dec −1 for OER in 1.0 M KOH. More importantly, it shows prominent stability in acidic and alkaline electrolytes. This study may open a new avenue for the design and fabrication of self-supported bifunctional electrocatalysts for water splitting. Graphic Abstract