Coordination adsorption of Ag(I) on cobalt-ferrous oxalates and their derived Ag/CoFe2O4 for catalytic hydrogenation reactions

Abstract Well-defined deposition of noble metal nanoparticles is attractive for the synthesis of heterogeneous metal catalysts with excellent activity, stability, and easy separability. Herein, a facile method combining surface coordination deposition with thermal decomposition has been proposed to fabricate Ag/CoFe2O4 composites as magnetic catalysts for hydrogenation reduction of 4-nitrophenol and 2-nitroaniline. This method involved the adsorption of silver ions on cobalt-ferrous oxalate through the surface coordination, and then the thermal decomposition into Ag/CoFe2O4. The characterizations of XRD, SEM, FTIR, BET, VSM, XPS and Element mapping were utilized to reveal that Ag/CoFe2O4 exhibited a magnetic saturation of 40.4 emu g‒1, a specific surface area of 58.8 m2 g-1, and an even distribution of metallic Ag on CoFe2O4 particles. Catalytic reduction tests of 4-nitrophenol and 2-nitroaniline indicated that the Ag contents in Ag/CoFe2O4 seriously affected the catalytic activity of the catalysts. Moreover, the durability test showed that Ag/CoFe2O4 still preserved ∼74.6% of the initial catalytic activity even at the 20th run.