Ag/CoFe₂O₄ as a Fenton-Like Catalyst for the Degradation of Methylene Blue

Surface plasmon resonance (SPR) effect of noble metal nanoparticles has been widely exploited in surface-enhanced Raman spectroscopy, optical biosensing, and photocatalysis. In this work, silver nanoparticles were deposited on the surface of cobalt ferrite (CoFe₂O₄) to prepare a composite Fenton-like catalyst. Such catalyst was utilized to degrade methylene blue under visible light through activating peroxymonosulfate (PMS). The effects of the loading and particle size of silver nanoparticles, the dosage of the catalyst, PMS concentration, and other variables on the catalytic efficiency were explored. The catalytic efficiency of the composite catalyst is 3.8 times higher than that of CoFe₂O₄ under optimal conditions. The enhanced catalytic activity can be ascribed to the SPR effect of silver nanoparticles, which can expand the absorption range in the visible region, promote the separation of photogenerated electron-hole pairs, and accelerate the conversion rate of M(III)/M(II) in CoFe₂O₄ (M=Co, Fe).