Enhanced Photocatalytic Properties due to Electron-rich Ti-ion Doping in ZnFe2O4 under Visible Light Irradiation

Abstract

The substitution effect of Ti4+ at the Fe3+ site in the spinel-phase ZnFe2O4 system has been studied and further optimized to fabricate an efficient photocatalyst. The material doped with an electron donor (Ti+4), ZnFe2-xTixO4, with an optimum composition of x = 0.06 exhibited a unchanged band gap, which generated two times higher photocurrent and showed an enhanced quantum yield (upto 0.77%) for photodecomposition of a H2O-CH3OH mixture compared to the undoped material under a visible light (lambda >= 420 nm). In contrast, the material doped with very high concentration of Ti revealed deteriorated photochemical properties due to constituent impurity phases. The higher electron density caused by n-type doping seemed to be responsible for the more efficient charge separation in ZnFe2-xTixO4 (0.01 < x < 0.09), and hence, the high photocatalytic activity