Prepareation And Photocatalyic Properties Of B Phase TiO₂ Photocatalytic Material Based On Ag,Cu Plasmon Resonance Effect

With the rapid development of society,the demand for energy is increasing exponentially.Because of the excessive use of fossil fuels,a large amount of greenhouse gases are produced.This leads to the problem of energy shortage and environmental problems are becoming more and more serious.Convert CO₂ gas into high value-added hydrocarbons,such as CO,CH₄,CH₃OH,C₂H₅OH,etc.This is a very challenging task in the field of chemistry and chemical engineering.TiO₂（B）is widely used in the field of photocatalysis because of its narrow band gap,non-toxicity and low cost.However,the shortcoming of short electron lifetime of T TiO₂（B）leads to low photocatalytic activity.Therefore,TiO₂（B）was modified to improve its photocatalytic performance.1.First of all,TiO₂（B）was prepared by hydrothermal method with P25 as the precursor,and the precious metal Ag with surface plasma resonance（SPR）effect was used as the co-catalyst.The composite photocatalyst Ag-TiO₂（B）with different ratios was obtained by impregnation method and hydrogen reduction method and applied to the reaction system of CO₂ and H₂O reaction.The effect of different content of Ag on the reactivity was investigated.The results show that the x Ag-TiO₂（B）sample is a lamellar nanostructure,and there is no obvious difference between the x Ag-TiO₂（B）phase and the TiO₂（B）phase.With the increase of Ag loading,the yields of CO and CH₄ increased first and then decreased.After 3 hours of simulated solar irradiation,the best photocatalytic effect was that the yield of CO and CH4 of 1%Ag-TiO₂（B）catalyst reached 564 and 100μmol/g,which were 3.76and 2.5 times of that of TiO₂（B）catalyst,respectively.This indicates that the modification of Ag can effectively and significantly improve the charge carrier separation efficiency and carrier life.2.In order to further improve the reactivity of TiO₂（B）catalyst,basic metal Cu which can enhance the adsorption of CO₂ was selected to modify TiO₂（B）catalyst.The effect of1%Ag/x Cu-TiO₂（B）composite photocatalyst on the activity of CO₂ and H₂O reaction was also studied.The results showed that the 1%Ag/0.5%Cu-TiO₂（B）composite catalyst had the highest catalytic activity,and the yields of CO and CH₄ were up to 860μmol/g and410μmol/g,respectively,after 3 hours of irradiation.In addition,the best catalytic effect of1%Ag/0.5%Cu-TiO₂（B）ternary catalyst was obtained,and the synergistic effect between Cu and Ag was further studied by various characterization methods.UV-Vis DRS shows that x Ag/x Cu-TiO₂（B）composite photocatalyst can greatly enhance the absorption of UV and visible light,and Ag nanoparticles have SPR effect.The PL spectroscopic analysis and photoelectrochemical test showed that the addition of Cu and Ag could effectively improve the separation efficiency and existence time of photogenerated charge carriers.The CO₂-TPD test showed that the effective adsorption of CO₂ mainly occurred on the surface of Cu nanoparticles,and the surface was the active site of the reaction between photogenerated electrons and activated adsorption of CO₂.The experimental and characterization results clearly show that the co-modification of Ag and Cu significantly improves the photocatalytic activity of TiO₂（B）,which is precisely because of the good synergistic effect between Ag and Cu.This paper provides an effective method to modify the traditional TiO₂（B）photocatalyst by co-modification of basic metal Cu and metal Ag with SPR effect,which has a practical application prospect of photocatalytic reduction of CO₂.