Phase controllable fabrication of MOF-derived iron nickel sulfides as Fenton-like catalysts for peroxymonosulfate activation: The phase transition effect induced variations in the mechanism and performance

This study constructed an iron-nickel bimetallic sulfide (FeNiS@C) with a controllable phase to significantly improve PMS activation and durability. The precise phase control and continuous phase transition were achieved by tuning the sulfuration temperature, and the phase transformation from Ni-rich (Fe, Ni)S 2 to Ni-poor (Fe, Ni)S 2 and Fe-doped NiS changed the d-band center and work function of FeNiS@C, which induced variation in the electron-donating ability and Ni charge in each phase further improving the electron-transfer rate and dominating HO•, SO 4 - • and 1 O 2 generation. The Ni-rich (Fe, Ni)S 2 phase exhibited a 21- and 9-fold increased bisphenol A (BPA) removal rate (0.251 min −1 ), excellent structural robustness (> 95 % reactivity maintained after cycling and long-term assays) and satisfactory anti-interference ability over the other two phases, demonstrating promising application prospects in actual wastewater. This work provides new insight into phase-controllable bimetallic sulfide catalyst preparation and phase transition mechanisms for heterogeneous Fenton-like systems.