The Preparation Of Cerium Oxide Matrix Composite Photocatalytic Materials And Their Performance Study For Photocatalytic Reduction Of CO₂

With the rapid development of the social,a large amount of fossil fuel are used that bring the energy crisis at the same time,also produced a large number of CO₂ etc.greenhouse gases,resulting in serious environmental problems.Photocatalytic conversion of CO₂ to hydrocarbon compounds by solar energy is deemed to a very effective strategies for simultaneously solve the energy crisis and environmental problems.Now,the core of the method is focus on the development of high efficient photocatalyst.But the conventional emiconductor photocatalysts have some problems such as low visible light responsive,quantum efficiency and difficult to apply etc.Thus developing new and efficient catalyst become the research focus in the field.Recently,studies have shown that alkaline oxide can effectively adsorb CO₂,benefits photocatalytic reduction of CO₂;Bi-based photocatalysts materials have high activity in visible light,thus have broad prospects in the field of photocatalysis;silver salts have strong photocatalytic activity that is conducive to the photocatalytic reduction reaction.Therefore,the main research content of this project is the preparation of alkali oxide materials CeO₂ based composite Bi₂MoO₆ and silver salts materials,with the performance of photocatalytic reduction of CO₂ conversion hydrocarbon compounds.（1）Bismuth materials has high visible light activity,and the alkaline oxide is favourable for CO₂ photoreduction.These CeO₂/Bi₂MoO₆ microspheres composites photocatalysts were prepared through the combination of homogeneous precipitation and calcination method,they are used to study the performance of the photocatalytic reduction of CO₂.Photocatalytic performance of the CeO₂/Bi₂MoO₆ composites material are better than Bi₂MoO₆ and CeO₂.When the CeO₂ load is 5 wt%,after 4h illumination,the yield of methanol and ethanol is highest,about 32.5 and 25.9 μmol gcat-1,respectively,which is 1.94 and 4.2 times higher than that of pure Bi₂MoO₆ and CeO₂.According to research,the introduction of CeO₂ effectively improved the visible light activity of Bi₂MoO₆,and formation of heterojunction reduces the photoproduction electron-hole recombination rate,conducive to the catalyst for the adsorption capacity of CO₂ that effectively improve the activity of photocatalyticreduction of CO₂.（2）The alkaline oxide have CO₂ adsorption capacity and Ag salts have high photocatalytic activity.The flower-like CeO₂ was synthesized by solvothermal and calcination method,then Ag/Ag₃PO₄/CeO₂ was synthesized by co precipitation and photoreduction method,which was used for photocatalytic reduction of CO₂.Compared with the pure Ag₃PO₄ and CeO₂ materials,the visible light response ability of Ag/Ag₃PO₄/CeO₂ composite material is improve significantly.The best effect for composite is load 15wt% Ag₃PO₄,methanol and ethanol yield of after 4h illumination is 42.5 and 31.5 μmol gcatal-1,respectively,which is about 2.7 times of CeO₂.Through to training the experiment research shows that CeO₂ load Ag/Ag₃PO₄ can formed Z-scheme heterojunction that facilitates photoinduced electron hole separation,thus Ag/Ag₃PO₄/CeO₂ have good photocatalytic reduction performance,and CeO₂ has basic sites,can adsorption CO₂ which is possible conducive to the photocatalytic reduction of CO₂.