Study On Preparation And Properties Of Black Titanium Dioxide Photocatalyst Loaded With CuO

The emission of volatile organic compounds（VOCs）is a serious hazard to human,especially for benzene series with high content,high damage.It has become the focus of relevant experimental research.For the treatment of such pollutants,photocatalysis as a kind of clean and non-polluting treatment technology is utilized to remove the low concentration gaseous organic,which performs excellently.In this study,the Cu-BTC（BTC=1,3,5-benzoic acid）was loaded on the surface of TiO₂ which used to be the carrier.The Cu element was highly distributed in organic metal site,After destroying the Cu-MOF structure,the Cu was uniformly dispersed on the surface of the carrier.Furtherly,the catalyst was blackened to obtain a novel black TiO₂ catalyst CuO-TiO₂（mb）with highly dispersed CuO.The characterization of the catalyst showed that the MOF precursor effectively increased the dispersibility of CuO during the synthesis of CuO-TiO₂（mb）,and the average particle size of the catalyst CuO-TiO₂（d）prepared by the impregnation method reduced from 1.41μm to 0.20μm.The surface area of CuO-TiO₂（mb）photocatalyst was as high as139.24 m²/g and the particle size was 0.17μm,which was characterized by XPS,HR-TEM and adsorption desorption experiments.According to the results of UV-Vis DRS and PL,CuO-TiO₂（mb）showed a narrow band gap（1.36 e V）and low electron hole recombination rate,and exhibited excellent photoresponsive performance,especially in the visible region.Compared with CuO-TiO₂（d）,it was found that during the process of calcining MOF precursor,part of Cu changed from Cu²⁺to Cu⁺.The blackening process exacerbated this transition,and the oxygen vacancies of the catalyst increased,hindering electrons and vacancies.Combined with experimental of photocatalytic performance and density functional theory（DFT）calculations,it was found that Cu-O,Cu-Ti impurity states and oxygen vacancies caused additional energy levels,thereby reducing the band width.During photocatalytic reaction,photogenerated electrons and holes reacted with H₂O andO₂ to form·and·₂^-,which reacted with the target.Furtherly,Ti⁴⁺/Ti³⁺and Cu²⁺/Cu⁺convert to each other,which enhanced the adsorption of H₂O andO₂ by the catalyst.The experiments were carried to compare the degradation efficiency of catalysts and intermediates under ultraviolet and visible light.The results showed that the efficiency of CuO-TiO₂（mb）increased by 2.45 times as CuO-TiO₂（d）;after the dispersibility of CuO was improved,the catalyst efficiency was increased by 0.9 times;after the blackening treatment,the catalyst efficiency was increased by 0.8 times,furtherly,the efficiency of CuO-TiO₂（mb）was tested under different concentrations of H₂O andO₂.It was found that the photocatalytic reaction can be completed in the case where H₂O orO₂ existed alone,and H₂O was more favorable for the improvement of the catalytic reaction efficiency.The two components simultaneously had a synergistic effect on the reaction.This study shows that CuO-TiO₂（mb）is a good photocatalyst for photocatalytic decomposition of toluene and xylene.