Photocatalytic activity evaluation of tetragonal CuFe 2O 4 nanoparticles for the H 2 evolution under visible light irradiation

Abstract

Copper ferrite (CuFe 2O 4) nanoparticles have been successfully synthesized via a citric acid-assisted sol–gel method. For comparison, CuFe 2O 4 materials were also fabricated by solid-state reaction and co-precipitation method. Techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectrum (UV–vis DRS) have been employed to characterize the as-synthesized CuFe 2O 4 products. The CuFe 2O 4 sample prepared by sol–gel approach is composed of almost uniform nanoparticles with a grain size of about 80 nm and crystallized in a tetragonal crystal phase structure. Moreover, the photocatalytic activity of the as-obtained CuFe 2O 4 has been evaluated based on the H 2 evolution from aqueous oxalic acid solution under visible light irradiation. The effects of preparation routes, photocatalyst mass concentration, initial sacrificial reagent concentration and the durability of the as-obtained CuFe 2O 4 have been investigated in detail. The best result of the photocatalytic H 2 evolution activity (1.72 mmol h −1 g cat −1) was obtained over the sol–gel synthesized CuFe 2O 4 nanoparticles when the photocatalyst concentration is 1.0 g l −1 and the oxalic acid concentration is 0.05 M.