Synergy of nanoclusters/single atoms regulates sustainable oxidation pathways for self-motivated Fenton-like...

Synergy mechanism of nanoclusters/single atoms as coexisting electron-rich centers for sustainable Fenton-like catalysis without oxidant addition remains unclear. In this study, a composite catalyst consisting of Fe₂P nanoclusters coexisting with Fe single atoms (Fe₂P/FeN₂P₂/C) was synthesized and utilized in two catalytic systems: one with zero-peroxymonosulfate (PMS) addition and the other with low-PMS addition. Results indicated that Fe₂P/FeN₂P₂/C catalyst with electron-deficient region could adsorb pollutants via π-π bond and extract electrons from pollutants to the atomic FeN₂P₂/C as electron acceptor, and this self-motivated process in PMS-free system could be modulated by the Fe₂P nanoclusters via dynamic synergistic effects. In addition, electron-donating capacities of pollutants, that is, pollutants with stronger electron-donating capacity exhibited stronger driving force for electron transfer from the pollutants to the Fe₂P/FeN₂P₂/C catalyst. In contrast, PMS-addition Fe₂P/FeN₂P₂/C systems involved both the self-motivated process in PMS-free Fe₂P/FeN₂P₂/C and PMS-activation process with complex pathways. Furthermore, PMS-free and PMS-addition Fe₂P/FeN₂P₂/C systems have been further applied to two catalytic modules for a certain long-term and enlarged operation. Unraveling this synergy mechanism will enable the design of adaptive catalytic systems capable of tackling complex real-world wastewater matrices, ensuring robust contaminant removal across diverse industrial and municipal water treatment scenarios.