| In essence, rapid economic development bring more and more creature comforts for people, but at the same time it also puts enormous pressure on ecological environment. How to control the environmental pollution is an urgent problem that need to be solved at present. Early treatment methods can not meet the current processing requirements. As a friendly environmental material, TiO2has been becoming a research focus for environment control because of its non-toxic, chemical stability and high photocatalytic activity. In the presence of photo catalyst with enough illumination, contaminants can be degraded into CO2and H2O. Thus, TiO2has been widely used in sterilization, deodorization, self-purification and other fields. Although, there are many incomparable advantages compared with other materials, TiO2still could not be widely used because of its high electronic-hole recombination rate, lacking adsorption capacity and other weaknesses. In this work, a mesoporous C-TiO2composite materials were synthetized by template-based method. The adsorption ability and photocatalytic activity of C-TiO2composite materials were investigated, The synergistic effect of the adsorption and photocatalysis was evaluated, and the synergistic mechanism was discussed. Conclusions obtained are as follows.Mesoporous TiO2was prepared by tetrabutyl titanate as titanium source and cetyl trimethyl ammonium bromide (CTAB) as the template agent. The influences of different doses of template, inhibitor, acetylacetone, pH, stirring rates and reaction temperatures on structures and crystal forms of TiO2were investigated. The preparation parameters were also optimized.C-TiO2composite materials modified by carbon were synthetized. Characterization methods such as XRD, SEM, TEM, XPS and N2adsorption/desorption analysis were used to research the morphologies and structures of C-TiO2composite materials. It is found that C and TiO2could form an organic whole in coating way. The general thickness of carbon coating on TiO2can be one nanometer and the thickest one may be five nanometers. Agglomeration of TiO2particles is restrained in the existence of carbon. Sizes of TiO2 particles are decreased and dispersibilities of the particles are enhanced, leading better crystalline of C-TiO2materials. Specific surface area of C-TiO2composites is much larger than that of pure TiO2because of the abundant pore structure. Meanwhile, electro negativity is increased leading binding energy of Ti2p enlarged.C-TiO2materials were manufactured by multistep calcination method which could provide steadied stress and improve pore structure stability. Organic matters were fully broken or cracked in low temperature, so that pressures of pore wall generated in high temperature by decomposition of matters were reduced. According to the researches, particle size is aggrandized with time, and the average grain diameter is largest in high temperature. Optimum calcination time of all three temperature zones is2hours.Properties of adsorption and photocatalytsis of C-TiO2materials were studied systematically based on experiments dealing with methyl orange. Effects of different amounts of template and inhibitor, pH, calcination temperature and time on adsorption and photocatalytsis were explored. It is found that micropores in C-TiO2materials is dominated to adsorption, and enhancement of crystalline and diminution of particle size is facilitated to photocatalysis.Excellent properties of C-TiO2results from synergistic effects of the adsorption of porous carbon and the photocatalytsis of TiO2. A pollutant-rich environment on the surface of TiO2is provided by the adsorption of porous carbon. Porous carbon can also work as electron acceptor and transport medium, lowering the electronic-hole recombination rate, which resulting more hydroxyl radicals to be produced. As a consequence, the degradation rate of pollutants are improved. |
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