| With the population growth and the development of modern industrialization, the global demand for energy is growing, and after the burning of over-exploitation of huge energy consumption for hundreds of yeas, coal, oil and natural gas and other fossil fuels are causing the main greenhouse gas CO2 increased dramatically, undermining the balance of nature of the carbon cycle, leading to the global warming. In addition, a large number of domestic sewage and industrial wastewater pollution are causing the serious environmental pollution and ecological damage. The semiconductor material can photocatalytic reduce CO2 to hydrocarbon fuels and degrade pollutants of concern effectively. TiO2 has advantages of low-cost, non-toxic, good stability, etc., and is widely used in the photocatalytic decomposition of H2O, CO2 reduction and photocatalytic degradation of organic pollutants. Due to poor adsorption of CO2, the light-generated electron-hole recombination and narrow spectral response range and other factors, the photocatalytic CO2 reduction performance is limited. In this study, a simple and rapid method for the silver mirror reaction synthesized Ag/TiO2 composites, and applied photocatalytic reduction CO2. The main contents are as follows:(1)The photocatalytic reduction of CO2 over the Ag/TiO2 composites prepared with a simple silver mirror reaction method was explored under UV-visible irradiation in both gas-phase (CO2+ water vapor) and aqueous solution (CO2-saturated NaHCO3 solution) systems. The as-prepared Ag/TiOo2 nanocomposite exhibits an efficient photocatalytic activity due to surface plasmonic resonance and electron sinker effect of Ag component, which was found to be closely related with the size and loading amount of Ag. The rapid silver method is effective to curb the size of Ag, so the photocatalytic activity can be improved. Diverse organic chemical products were detected, mainly including methane and methanol as well as small amount of C2 and C3 species such as acetaldehyde and acetone. The possible photocatalytic mechanisms were proposed. This artificial photosynthesis process may give a prosperous route to removal of CO2 while simultaneously converting CO2 to valuable fuels based on highly efficient photocatalysts.(2)We designed the photocatalytic fuel cells (PFCs) using the TiO2 thin film electrode as anode and the Cu2O film as cathode. The TiO2 thin film was used to degrade organic pollutants and the Cu2O film was used to convert the CO2 to hydrocarbon fuels. The distance between the anode and cathode was also optimized. The results showed that the efficiency of the reduction of CO2 to hydrocarbon fuels was higher than other photocatalytic reduction of carbon dioxide obviously. The photocatalytic degradation of industrial wastewater and the reduction of CO2 to hydrocarbon fuels were investigated. The results demonstrate that the proposed PFCs can achieve organic pollutant degradation and simultaneously recover the released chemical energy of pollutants.(3)Au/Cu nanoparticles were supported on TiO2 surface, due to the small size of the metal particles, metals’SPR effect, Au and Cu not only to improve the catalytic efficiency in visible light, but also to control CO2 reduction products by adjusting the active site of in liquid phase. The experiment is to modify the semiconductor photocatalytic materials and explore new semiconductor material in response to extend the scope of existing photocatalytic materials, followed by changing the composition of the catalyst to control the type of product, so that the product reaches a regulatory nature. |
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