Preparation And Evaluation Of Composite Photocatalysts Of Sulfide For Reducing CO₂

In recent years, the concern about climate issues continues to heat up in the world. CO2 is the main gas of greenhouse effect to globally warm. CO2, accounted for about 80% of the greenhouse gases, is fixed and reused by technology to be a novel way for the development of new energy, In addition, as the use of renewable energy solar excited photocatalytic reduction of CO2 combines fossil fuel consumption and CO2 conversion to new fuels, which possesses the advantages of utilization and has attracted national attentions from governors and researchers. Photocatalytic reduction of CO2 by means of catalysts after photons or appropriate light excited to produce the electron- hole pair, where the electron reduces CO2 through active intermediates involved in the reaction scheme, it is the artificial photosynthesis,that converts light energy into chemical energy. Because of the chemically inert of CO2, its activation is difficult, additional energy has to input for promoting the action of photocatalysts in the photocatalytic reduction of CO2. Therefore, the photocatalytic reduction process of CO2 should introduce photocatalyst. Moreover, in order to improving the photocatalytic conversion efficiency in reduction reaction of CO2, the key still lies in finding and developing photocatalyst with high catalytic efficiency and high selectivity. My thesis is about the preparation of composite photocatalysts by hydrothermal method, and methanol is taken as a solvent for the catalytic reduction of CO2. The research includes the following elements:1. Bi2S3, Sb2S3 catalysts were synthesized by hydrothermal methods, their photocatalytic activities were tested at different conditions.2. The as prepared Bi2S3-Cd S photocatalyst has a great variation in the catalytic activity under different test condition. For different compositions, different sulfur sources as well as different reaction time, whether the presence or absence of the surfactant under preparation gave a great change in the catalytic activity, wherein 16 h, 70% of the maximum catalytic efficiency, Different sulfur sources affected a little, but reaction time of hydrothermal synthesis and the composition affected greatly on the specific surface area of the composite catalysts and activities3. As prepared Cd In2S4-In(OH)3 photocatalyst, showed a small specific surface area and formed a spherical structure to increase the contact area, so a high activity was observed. The influence of different preparation conditions on the catalytic activity was studied too.