An Efficient Electrocatalyst Based on Vertically Aligned Heteroatom(B/N/P/O/S)‐Doped Graphene Array Integrated with FeCoNiP Nanoparticles for Overall Water Splitting

Abstract Iron group metal phosphides (IMPs) are one of the most promising substitutes for non‐noble electrocatalysts in overall water splitting. In this work, an electrocatalyst system consisting of different vertically aligned heteroatom‐doped graphene arrays (X‐rGO, X = N, P, B, O, S) integrated with FeCoNiP nanoparticles (FeCoNiP@X‐rGO, X = N, P, B, O, S) is prepared for overall water splitting. The unique vertical structure and the synergistic effect between the P in P‐rGO and the P in FeCoNiP leads to the excellent electrocatalytic performance of FeCoNiP@P‐rGO by exhibiting low overpotentials (121 and 216 mV) at a current density of 10 mA cm⁻² for hydrogen evolution reaction in 1 m KOH and 0.5 m H₂SO₄, respectively. As well as a low overpotential (354 mV) at a current density of 10 mA cm⁻² for the oxygen evolution reaction in 1.0 m KOH. The FeCoNiP@P‐rGO electrocatalyst exhibits an outstanding durability toward overall water splitting in alkaline electrolytes, and excellent Faraday efficiency (about 92%) as well. This work provides an insight in proper tuning and the development of appropriate substrates for IMPs and other transition metal compounds toward cost‐effective and high efficiency electrocatalysts for water splitting reactions.