Construction And Properties Of 2D PbTiO₃ Based Composite Photocatalytic Materials

Due to its advantages of mild reaction conditions and direct conversion of light energy into chemical energy,photocatalysis technology has attracted much attention from researchers.Its core is to develop highly efficient semiconductor photocatalysts.Single crystal single domain Pb Ti O₃（PTO）nanoplates have unidirectional built-in electric field,which can promote the separation of photogenerated carrier and prolong the carrier lifetime in the photocatalytic reaction stage,so they are widely studied in the field of photocatalysis.However,in practical application,there are still some problems,such as high carriers recombination rate and narrow optical absorption range.These problems affect its further development.In this paper,using single crystal single,domain PTO as the base material,two kinds of composite photocatalysts were synthesized by three modification methods,including heterostructure construction,defect engineering and precious metal deposition.The photocatalytic reaction performance and mechanism were studied,and the following innovative achievement were obtained:1.An indirect method was used to introduce a large number of oxygen vacancies on the surface of PTO nanoplates to improve the light absorption in visible light without affecting the photocatalytic activity.Firstly,PTO@BiOCl heterojunction nanoplates were prepared by hydrothermal method,and then PTO@BiOCl-OVs heterojunction nanoplates containing oxygen vacancies were synthesized by UV reduction method.When the content of loaded BiOCl was low（3%）,the photocatalytic activity of PTO@BiOCl-OVsheterojunction nanoplates was significantly increased compared with PTO nanoplates in the degradation of Rh B in visible light.In addition,3%PTO@BiOCl heterojunction nanoplates also showed good photocatalytic activity and stability in the degradation of TC.The reason for the improvement of photocatalytic activity can be attributed to the synergistic effect of oxygen vacancies on BiOCl,ferroelectric polarization and heterostructure,which not only increases the active site in the photocatalytic reaction,but also expands the light absorption of PTO under visible light,which ensures the separation efficiency of photogenerated carrier and promotes the generation of active species in the photocatalytic reaction.Finally,the photocatalytic reaction is accelerated.2.We have successfully prepared PTO@Pt heterojunction nanoplates with different mass ratios by secondary hydrothermal method.Under the irradiation of 300W xenon lamp（AM1.5G simulated sunlight）,the photocatalytic hydrolyzation hydrogen production rate of 1%PTO@Pt heterojunction nanoplates was 219.63μmol·h^-1·g^-1,it was significantly improved compared with PTO nanoplates.In this study,it is proved that the high activity of photocatalytic hydrolytic hydrogen production can be greatly improved because Pt nanoparticles with high activity have close interfacial contact with single crystal and single domain PTO,which reduces the transport distance of photogenerated carriers,improves the light absorption in the visible region,promotes the separation of photogenerated carriers and inhibits their recombination.In summary,we successfully prepared composite photocatalysts with high photocatalytic activity and good photocatalytic stability using single crystal and single domain PTO nanoplates as substrate by simple hydrothermal method.