Regulating spin state of Fe active sites by the P-doping strategy for enhancing peroxymonosulfate activation

Optimization of Fe-based heterogeneous catalyst for enhancing PMS activation was studies by an electronic structure regulation strategy. The single atom and nano-particle Fe-catalysts were then modified by P-doping on carbon support and tested for BPA degradation. Catalysts with P-doping led to 100 % BPA degradation in 30 min, much better than single atom and nano-particle control groups (56 % and 61 %). Experimental and DFT results revealed that P-doping increased the electron density of Fe and induced the transformation of Fe 3d electron spin state from low spin to medium spin, then the Fe 3d orbitals with high energy could better overlap with O 2p orbitals of PMS, promoting the electron transfer process from Fe to PMS and generation of hydroxyl radical. This work provides a deep understanding of spin state modulation for designing high-performance PMS activation catalysts.