Modulating photothermal properties by integration of fined Fe-Co in confined carbon layer of SiO nanosphere for pollutant degradation and solar water evaporation.

Environmental governance by photothermal materials especially for the separation of organic pollutants and regeneration of freshwater afford growing attention owing to their special solar-to-heat properties. Here, we construct a special functional nanosphere composed of an internal silica core coated by a thin carbon layer encapsulated plasmonic bimetallic FeCoO spinel (SiO@CoFe/C) by a facile self-assembled approach and tuned calcination. Through combining the advantage of bimetallic Fe-Co and carbon layer, this obtained nanosphere affords improved multiple environmental governing functions including peroxymonosulfate (PMS) activation to degrade pollutants and photothermal interfacial solar water evaporation. Impressively, fined bimetal (FeCo) species (20 nm) acted as main catalytic substance were distributed on the N-doping carbon thin layer, which favors electron transfer and reactive accessibility of active metals. The increasing treatment temperature of catalysts caused the optimization of the surface active metal species and tuning catalytic properties in the AOPs. Besides, the incorporation of Co in the SiO@CoFe/C-700 could enable the improved PMS activation efficiency compared to SiO@Fe/C-700 and the mixed SiO@Co/C-700 and SiO@Fe/C-700, hinting a synergetic promotion effect. The bimetal coupled catalyst SiO@CoFe/C-700 affords enhanced photothermal properties compared to SiO@Co/C-700. Furthermore, photothermal catalytic PMS activation using optimal SiO@CoFe/C-700 was further explored in addressing stubborn pollutants including oxytetracycline, sulfamethoxazole, 2, 4-dichlorophenol, and phenol. The free radical quenching control suggests that both the sulfate radical, hydroxyl radical, superoxide radical, and singlet oxygen species are involved in the degradation, while the hydroxyl radical and singlet oxygen play a dominant role. Furthermore, the implementation of a solar-driven interfacial water evaporation model using SiO@CoFe/C-700 was further studied to obtain freshwater regeneration (1.26 kg m h, 76.81% efficiency), indicating the comprehensive ability of the constructed nanocomposites for treating complicated environmental pollution including organics removal and freshwater regeneration.