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

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 H 2 SO 4 , 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.