Synthesis And Photocatalytic Degradation Of Rhodamine B Using TiO₂ Templated By Co-and Ni-immersed Tobacco Stems

Materials made by TiO₂ are highly active,fairly stable and at a low cost,and are the most widely-used photocatalytic ones in all photocatalytic techniques.Such TiO₂materials are now put into use in many industries such as photo-induced hydrophilic coating,waste-water disposal,hydrogen production,pesticide degradation and biological application.Although such TiO₂ materials are of significant advantage,problems still exist considering their limited abilities in absorption of visible light and conversion of light.It is,therefore,necessary to study modification of such TiO₂ materials,so as to raise the utilization of light.Up to now,biotemplating has been in massive use as a method of synthesis to efficiently boost the photocatalytic activity of TiO₂.This paper is to improve the photocatalytic activity of TiO₂materials,using biotemplating with a mix of transition metals,and this paper concludes as follows:（1）TiO₂ using tobacco stems as templates were successfully synthesized by biotemplating and solvothermal method,and were synthesized by immersing tobacco stems as templates in different concentrations of Co.Results show that（i）TiO₂ prepared by being immersed in Co and TiO₂ using pure tobacco stems as templates are better in material absorption band edge,specific surface area and photocatalytic activity;（ii）the optimal concentration of Co for soaking is 0.5%.The photocatalytic degradation efficiency of TiO₂-TCS-0.5Co is about 2.5 times the degradation rate constant of TiO₂-TCS using tobacco stems as templates,and 3.4 times the degradation rate constant of P25.（2）TiO₂ were successfully prepared by immersing tobacco stems as templates in different concentrations of Ni.Among such materials,when the concentration of Ni is0.5%,the removal rate of rhodamine B is the best,and the photocatalytic degradation rate is the highest,2.4 times the degradation rate constant of TiO₂-TCS synthesized by pure tobacco stems as templates.The introduction of Ni in such materials has huge influences in their specific surface area,band gap width and photocatalytic performance.（3）Different routes of synthesis for the preparation of materials are discussed.TiO₂that were synthesized by immersing tobacco stems as templates in Co,Ni and Ti sources in different orders were compared in their differences of performance and structures.Analyses of characterization results indicate that（i）in materials synthesized by two routes,there are slight differences in specific surface area,band gap width and actual content of transition metals,but are mostly the same in their appearances;（ii）samples immersed in Co,Ni and Ti sources successively are much better in photocatalytic performance.