Spindle-shaped cobalt-doped iron phosphide anchored on three-dimensional graphene electrocatalysis for hydrogen evolution reactions in both acidic and alkaline media

Exploitation of earth-abundant, highly active and noble metal-free electrocatalysts to utilise water splitting for hydrogen production over a broad pH ranges remains a substantial challenge. Herein, we report a spindle-like high-performance electrocatalyst of Co-doped FeP supported on a three-dimensional framework reduced graphene oxide (Co–FeP/3D RGO) by using earth-abundant materials (such as C and Fe). The porous internet-like graphene not only provides a three-dimensional framework for FeP growth to prevent its aggregation, but also accelerates its electrical conductivity and stability. The doping of heteroatomic Co further enhances the intrinsic activity of FeP. As expected, Co–FeP/3D RGO demonstrates a lower hydrogen evolution reaction (HER) overpotential (η₁₀ = 110.8 mV) and Tafel slope (53 mV dec⁻¹) in the acidic electrolyte and reveals low overpotential (137 and 190 mV) at 20 and 50 mA cm⁻². Besides, the catalyst also has excellent HER activity and stability in the alkaline electrolyte. This work may provide more opportunities and potential value for the rational design of HER electrocatalysts with a wide pH range of abundant non-precious metals on the earth.