无定形态H_3PW_(12)O_(40)/TiO_2光催化剂降解有机染料

Photodegradation of organic dyes catalyzed by amorphous H_3PW_(12)O_(40)/TiO_2 photocatalyst

以钛酸丁酯和磷钨酸为主要原料,采用溶胶-凝胶法制备H3PW12O40/TiO2光催化剂,采用红外光谱、X射线衍射、热重分析和比表面分析对光催化剂进行表征。结果表明,H3PW12O40/TiO2光催化剂为无定形态,比表面积202 m2·g-1,杂多阴离子保持了Keggin骨架结构。在TiO2中掺杂H3PW12O40,使催化剂的光响应范围扩展到可见光区,从而提高光催化活性。光催化剂对甲基橙、酸性红、罗丹明B和亚甲基蓝均有较好的光催化降解活性,催化剂易于分离,重复使用稳定性较好。对甲基橙降解的适宜条件为:1.7×10-5mol·L-1甲基橙溶液50 mL,H3PW12O40/TiO2光催化剂用量0.03 g,500 W碘钨灯照射60 min,此条件下,甲基橙脱色率可达到96%。

H3PW12O40/TiO2 photocatalyst was prepared via sol-gel method from tetra-butyl titanate and H3PW12O40/TiO2, and characterized by IR,XRD and TG-DTG. The results showed that H3PW12O40/TiO2 pho- tocatalyst was amorphous,with Keggin structured phosphotungstate anion and the specific surface area of 202 m2 · g^-1. Doping of H3PW12O40/TiO2 could extend the photoresponse range of TiO2 to visible region, resul- ting in efficient separation of photo-generated charge and hole ,and enhancement of photo-catalytic activity. H3PW12O40/TiO2 photocatalyst exhibited high photocatalytic activity for the degradation of organic dyes, such as methyl orange, acid red, rhodamine B and methylene blue. The catalyst was easily recycled with stable catalytic behavior. Methyl orange decoloration rate of 96% was attained under the optimum degra- dation condition of 1.7 x 10^-5 mol · L-1 methyl orange solution 50 mL,H3PW12O40/TiO2 catalyst dosage 0.03 g, irradiation time 60 min and 500 W halogen lamp irradiation.