Effect of co-doped La~(3+)/halogen on visible light photocatalytic activity of TiO_2

摘要

La~(3+)/halogen (F~-, Cl~- and Br~-) co-doped TiO_2 was synthesized by alkoxide hydrolysis method. The prepared La~(3+)/halogen TiO_2 photocatalysts with anatase phases and rutile phases were characterized with XRD, EDS, TEM and surface area analytic technology. Methyl orange was used as model pollutants to evaluate its visible light photocatalytic activity. The results showed that the co-doping of La~(3+) and halogen ions improved the surface area of TiO_2. Compared with 450°C and 650°C, La~(3+)/Cl~- and La~(3+)/Br~- co-doped TiO_2 calcined at 550°C exhibited much higher photocatalytic activity. The optimal doping ratio of La~(3+)/F", La~(3+)/Cl" and La~(3+)/Br" was 0.4, 0.6, and _(0.5) ((wt%)/(wt%)), respectively. Moreover, the degradation ratio of methyl orange on La~(3+)/halogen co-doped TiO_2 with the optimal ratio were all higher than the maximum degradation ratio on La~(3+), F~-, Cl~- and Br~- doped TiO_2 prepared by the same method.