Effect of intermediate ball milling on the synthesis of Cu-doped TiO2 nano-photocatalyst by sol–gel method

Abstract

AbstractIn this paper, Cu-doped TiO2 powder was prepared by sol–gel method and the influence of 1\u2009h intermediate ball milling before calcination on different properties was investigated. The powders were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA), diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and ultraviolet–visible spectrophotometer. Ball milling before calcination for 1\u2009h was sufficient enough to accelerate the calcination process and obtain small size of the powder particles. Calcined ball milled sample at 450\u2009°C for 2\u2009h revealed anatase TiO2 phase structure with average particle size of 180\u2009nm. The results showed that the synergistic effect of Cu doping and ball milling before calcination considerably narrowed the band gap of the synthesized TiO2 photocatalyst to 2.85\u2009eV. PL results confirmed an effective separation of electron-hole pairs by Cu doping and also intermediated ball milling. The best photocatalytic performance under visible light in degradation of methylene blue (MB) was achieved with the combined influence of ball milling before calcination and Cu doping on TiO2, whereby a degradation of about 66% was obtained. It was found that the degradation reactions of MB by prepared photocatalysts followed the pseudo-first order reaction kinetics. In comparison, ball milling of TiO2 and Cu-doped TiO2 after calcination showed the undesirable effect on photocatalytic performance. In addition, nano-photocatalyst showed the good stability under visible light after recycling.\n Cu-doped TiO2 nano-photocatalyst with an average particle size of 180\u2009nm and a band gap of 2.85\u2009eV was synthesized and MB degradation of about 66% was obtained after 120\u2009min visible light irradiation.HighlightsCu-doped TiO2 powder was synthesized by combined sol–gel and mechanical milling.Effect of 1\u2009h intermediate ball milling before calcination was investigated.Synergistic effect of Cu doping and ball milling narrowed the band gap of TiO2.Effective separation of electron-hole pairs by Cu doping and milling was confirmed.Photocatalytic degradation of 66% for methylene blue in visible light was obtained.