In-situ self-grown binder-free FeCr co-doped Ni3P/NF with green phosphorus source and enhanced water splitting performance

• Green synthesis of binder-free FeCr-Ni3P/NF without toxic PH3 emission. • FeCr-Ni3P/NF exhibits excellent bifunctional electrocatalytic performance for OER and HER. • Distinct surface reconstruction into NiOOH (OER) and Ni(OH)2 (HER) contributes to enhanced catalytic activity. Water electrolysis is vital for producing green hydrogen, yet widespread deployment is impeded by the steep cost of noble-metal electrocatalysts. In this work, a binder-free Fe and Cr co-doped Ni 3 P electrocatalyst (FeCr-Ni 3 P/NF) was successfully fabricated via direct growth on NF, with biomass-derived sodium phytate serving as the P supplier to eliminate the risk of toxic PH 3 emission in conventional synthesis. Benefiting from the unique nanosheet-layered structure and electronic synergy, FeCr-Ni 3 P/NF displays outstanding bifunctional electrocatalytic performance and durability in 1 M KOH. With low overpotentials of 270 mV (OER, 100 mA cm -2 ) and 137 mV (HER, 10 mA cm -2 ). Subsequent structural characterizations further reveal the distinct surface reconstruction behavior of FeCr-Ni 3 P/NF under different catalytic conditions. The pre-catalysts are reconstructed into NiOOH after OER stability tests and converted to Ni(OH) 2 after HER tests. Moreover, the composite structure formed by the precatalyst and in-situ generated nickel (oxy)hydroxide further enhances the overall catalytic performance.