Preparation Of Ti₃C₂ MXene-Based Composites And Their Application In Photocatalytic Reduction Of CO₂

The excessive combustion of fossil fuels has resulted in significant CO2 emissions and energy shortages.Photocatalytic technology can use the energy in sunlight with the prepsence of photocatalysts to reduce CO2 into usable substances,which can solve the increasingly serious greenhouse effect and energy shortage problems to achieve the goal of carbon peak and carbon neutrality.In the process of photocatalytic CO2 reduction reaction,selecting a suitable photocatalyst is crucial for the reaction efficiency.However,a single semiconductor-based photocatalyst has poor performance and requires modification methods such as combination with cocatalysts to improve its performance.Traditional precious metal cocatalysts are expensive and not conducive to the economic efficiency of the reaction.This article focuses on the different properties and advantages of Ti3C2 MXene and develops three types of photocatalysts to study the effect of synthesizing Ti3C2 MXene based composite materials on photocatalytic CO2 reduction under different binding methods.The specific research work is as follows:1.TiO2 nanoparticles were grown in situ on Ti3C2 MXene by a simple calcination method,and then a composite catalyst CuS@TiO2/Ti3C2 was synthesized by a hydrothermal method and used for photocatalytic CO2 reduction.Under simulated sunlight,the composite material exhibited the best photocatalytic CO2 reduction activity,with a corresponding CO production rate 2.3 times that of TiO2/Ti3C2.At the same time,due to the effective separation of photo generated electrons and holes,multi electron reactions can occur,resulting in an additional amount of CH4 with more practical application value.At the same time,Ti3C2 MXene as a substrate material can effectively inhibit the photo corrosion of CuS,enhance the stability of the catalyst,and is beneficial for practical applications.2.Nitrogen doped mesoporous CeO2(NCe)was synthesized by calcination,and then uniformly bound to the surface of ultrathin MXene nanosheets using a simple electrostatic selfassembly method to prepare a nitrogen doped mesoporous CeO2/2D Ti3C2 MXene(NCeM)Schottky heterojunction.Single layer Ti3C2 MXene nanosheets provided uniformly dispersed CeO2 distribution,more active site and enhanced CO2 adsorption capacity,and inhibited the separation of photogenerated electrons and holes by constructing Schottky heterostructures.The composite material is used for photocatalytic CO2 reduction,and its reduction efficiency and CH4 selectivity are significantly improved.3.Octahedral CeO2 was synthesized by a traditional hydrothermal calcination method,and then the composite material CuO@CeO2 was further synthesized by a hydrothermal method,and CuO@CeO2 was loaded on the Ti3C2 MXene nanosheets by a simple electrostatic selfassembly method to synthesize three Metal-composite CuO@CeO2/Ti3C2 MXene for photocatalytic CO2 reduction.Through the effective migration of photogenerated electrons from CuO and CeO2 to Ti3C2 MXene,the composite material exhibited good stability and significantly improved reaction activity,proving the important role of Ti3C2 MXene nanosheets in multicomponent composite photocatalysts.