Effect of Ba-La co-doping on degradation of methylene blue dye by TaON
Ba-La co-doped TaON photocatalysts were prepared by an improved solvothermal-high temperature nitridation method.The crystal structure,micromorphology and optical properties were analyzed by XRD,SEM,XPS,and the photocata-lytic performance was evaluated by degradation of methylene blue(MB)solution.The results showed that Ba and La co-dop-ing did not change the crystalline structure of TaON,but both of them replaced part of Ta5+ in the TaON lattice with ions,which resulted in slight changes in the morphology of TaON.The co-doped TaON had a smaller grain size and a narrower band gap,which further improved the light absorption ability and photogenerated carrier separation efficiency.The degrada-tion efficiency of the co-doped TaON for MB under visible light was dramatically improved,and the best TaON photocata-lytic performance was achieved when n(Ba)/n(La)was 1.00,with the degradation rate of MB reaching 86.5%in 120 min,which was about 25%higher than that of pure TaON,and the reaction was conformed to the first-order kinetic law.In addi-tion,h+ and·OH were the main active radicals in the degradation process of MB solution,and it still had good stability and catalytic performance after four cycles of catalysis.
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