Thermo-photocatalytic degradation of benzene on Pt-loaded TiO2/ZrO2

A TiO2/ZrO2 powder was prepared using TiOSO4 and ZrOCO3 through a homogeneous co-precipitation process. The Pt-loaded TiO2/ZrO2 catalyst was obtained by loading Pt onto the powder via an incipient wetness approach. The catalyst samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, degree of dispersion, N2 adsorption–desorption (BET) and X-ray photoelectron spectroscopy (XPS). It was found that the catalytic activity was significantly affected by Pt loadings, reduction temperatures and the reaction temperatures. A synergetic effect took place between photocatalytic and thermocatalytic reactions when benzene was engaged in the thermo-photocatalytic degradation. For 80 mg m−3 benzene, the kinetic constant of thermo-photocatalysis was 1.26, 1.64, 2.15 and 2.93 times higher than these ones of single photocatalysis, when 90 °C, 120 °C, 150 °C and 180 °C was applied to the reaction, respectively. The rate constant at 150 °C, presented by the thermo-photocatalytic reaction, was 2 times higher than it was obtained from the photocatalytic reaction, under various experiment conditions. It was also found that, highly concentrated benzene, in a concentration of 1000 mg m−3, was degraded effectively by thermo-photocatalysis and the mineralization rate reached 90.3% within 16 h. The thermo-photocatalytic technique was considered to have practical application foreground in the degradation of highly concentrated benzene.

Graphical abstractThis observation revealed that the kinetic constant of thermo-photocatalysis was higher than the rate constant sum of the photocatalytic and the thermocatalytic reaction. It suggested that there be a synergetic effect between photocatalytic and thermocatalytic reactions.Figure optionsDownload full-size imageDownload high-quality image (92 K)Download as PowerPoint slideHighlights► Easy reduction of Pt4+ at room temperature. ► Minor difference of Pt0 content, however, noticeable difference of activity. ► An obvious synergetic effect between photocatalytic and thermocatalytic reactions. ► A mechanism proposed about thermo-photocatalysis.