Preparation Of Modified TiO₂ Nanotubes And Photoelectrocatalytic Reduction Of CO₂ To Carbonaceous Substance

The continuous increase of carbon dioxide?CO₂?in the atmosphere has caused worldwide climate change due to the overuse of fossil fuels as the primary energy source.In order to minimize the greenhouse effect caused by CO₂ and close the present carbon cycle,a variety of technologies and approaches to capture and reuse the atmospheric CO₂ as a carbon feedstock have been developed.Among these technologies,photoelectrocatalytic conversion of CO₂ as an emerging frontier technology has been accepted and recognized by more and more research institutions because of its mild reaction conditions and the use of solar energy.As excellent nano-photocatalysts,TiO₂ NTs are widely used in photocatalytic conversion of CO₂,but up to now,TiO₂ NTs photocatalytic conversion of CO₂ is limited by the disadvantages of low yield,low selectivity,and low stability.In this paper,TiO₂ NTs were mainly used as research objects,and various modified TiO₂ NTs prepared by photoelectro-deposition method were used for photoelectrocatalytic conversion of CO₂.The photoelectric properties of the TiO₂ NTs are further studied,and the research results demonstrate that:1.By improving the preparation parameters of in-situ secondary oxidation,double-layered titanium dioxide nanotubes?TiO₂ NTs?with smooth walls,stable structure and large specific surface area were prepared.2.Five new types of supported double-layered titanium dioxide nanotubes were prepared using special photo-electron deposition methods?Ag-TiO₂ NTs,Au-TiO₂ NTs,Pt-TiO₂ NTs,Ni₂O₃-TiO₂ NTs,Fe₂O₃-TiO₂ NTs?.3.The actual optical activation area of Fe₂O₃-TiO₂ NTs prepared under optical conditions was 2.26 times higher than that under electrochemical conditions.In addition,the valence of Fe ions in Fe₂O₃-TiO₂ NTs can change with the reaction wavelength,affecting the conversion path of CO₂ reduction to different products.4.Innovatively,CO₂ was selectively reduced to varying products by adjusting the voltage and wavelength of light in photoelectrocatalytic conditions.The yield of HCOOH is quantified by 81.98?mol·h^-1·cm^-2,and the selectivity is up to 99%.