Fabrication Of CeO₂-based Composite Photocatalyst For Efficent Photocatalytic Reduction Of Co₂

The continuous consumption of fossil energy has led to the energy crisis and the massive emission of gases such as CO₂.CO₂ in the atmosphere causes environmental problems such as the greenhouse effect.Photocatalytic CO₂ reduction technology is a green and environmentally friendly technology,which can reduce CO₂ into a variety of products such as HCOOH,CO,CH₃OH.CeO₂ is a common semiconductor,it is easy to synthesize,environmental protection,good performance,that is widely used in the field of photocatalysis.However,CeO₂ also has some defects,such as easy recombination of photogenic carriers,low utilization rate of light energy and easy agglomeration,which limit its photocatalytic performance.In order to solve the above problems,this paper modified CeO₂,respectively constructed rodlike attapulgite?ATP?modified CeO₂ composite photocatalyst?CeO₂/ATP?and biomass modified CeO₂ photocatalyst?Note:non-biological carbon modified photocatalyst?,used for photocatalytic reduction of CO₂.The specific research contents are as follows:?1?The CeO₂/ATP composite photocatalyst with rodlike structure cross with spindle structure were synthesized by high temperature calcination.XRD,TEM,FT-IR,Raman,UV-vis,PL,photocurrent impedance measurements and so on were used to test the photocatalytic performance of CeO₂/ATP composite photocatalyst.The activity of the catalyst was evaluated by the production of the reaction product of photocatalytic reduction of CO₂.Under the irradiation of ultraviolet light source,CeO₂/ATP composite photocatalyst can reduce CO₂ to CO and CH₄.The maximum yield after 5 h of the photocatalytic reaction is 309.44 mol g^-1 h^-1 and 184.33 mol g^-1 h^-1 for CO and CH4,which is about 3 times of that of pure CeO₂.The performance improvement of the composite photocatalyst is attributed to the addition of ATP.The conductivity of ATP can improve the separation efficiency of photogenerated electron holes.The introduction of ATP also can prevent the stacking and agglomeration of CeO₂,and further increase the active sites of CO₂ adsorption and reduction,which improve the photocatalytic activity of CeO₂.?2?The biomass modified CeO₂ was prepared and studied its photocatalytic reduction of CO₂ properties.Common alternanthera philoxeroides for a living material source,the biomass modified CeO₂ photocatalyst were prepared by hydrothermal method and high-temperature calcining method.The properties of the prepared materials were characterized by different measurements and methods,and the activity of the catalyst was evaluated by the amount of CO produced by photocatalytic reduction of CO₂.After 6 h the yield of CO was 21.14 mol g^-1 h^-1,which was 7.4 times that of pure CeO₂.Compared with pure CeO₂,biomass modified CeO₂ photocatalyst has higher activity.On the one hand,the introduction of biomass provides a microenvironment for the growth of CeO₂,which greatly changes the growth morphology of CeO₂ to other crystal surfaces,increases the specific surface area and provides more active sites.On the other hand,it is the biomass modified photocatalyst that speeds up the electron transport so that the electrons and holes can be separated effectively.