TiO2-coated/activated carbon composites (TCS) were prepared by supercritical pretreatment and sol-gel processing. The prepared TCS were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption analysis. The photocatalytic performances of the composites were evaluated by the decolorization of an acid red 27 solution. The results show that the TCS have higher photocatalytic activity than bare TiO2 because of the smaller crystalline size of TiO2 and the higher amount of adsorbed acid red 27 as well as hydroxyl radicals. The photocatalytic activity of TCS increased and then decreased with an increase in surface area. The kinetic behavior of the photocatalytic degradation of acid red 27 over various composites is described in terms of a modified Langmuir-Hinshelwood model. The kinetic results clearly indicate differences in the photocatalytic activity of TCS, which is mainly attributed to interactions between the surface areas and the adsorption strength. TCS3 gave the highest photocatalytic activity with an optimal adsorption strength resulting from its moderate surface areas.%通过超临界预处理和溶胶-凝胶过程,制备TiO2/活性炭复合体(TCS),利用X射线衍射,X光电子能谱和氮气吸附-解吸分析对其结构特征进行表征,以酸性红27的光催化降解评价复合体的光催化活性.结果表明:TCS光催化活性比纯TiO2大,归功于TiO2小晶粒尺寸,对酸性红27和羟基自由基高的吸附量.TCS复合体对酸性红27的降解效率随其比表面积的增大先升高后降低.通过改进的Langmuir-Hinshelwood模型对酸性红27在不同的复合体上光催化降解动力学行为进行描述,表明TCS光催化活性的差异主要是由比表面积和吸附强度相互制约所引起.TCS3由于具有适当的比表面积和恰当的吸附强度而具有最高的光催化活性.
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