海绵状Ag2O/ZnO复合光催化剂的制备及对甲醛的可见光降解

为克服纳米ZnO晶体可见光光催化活性低的缺点，以六水合硝酸锌、六亚甲基四胺和二水合草酸为原料，采用液相共沉淀-热分解法制备了六方纤锌矿型海绵状ZnO，然后在碱性条件下复合纳米Ag₂O颗粒，得到海绵状Ag₂O/ZnO复合光催化剂，并采用XRD、FTIR、紫外-可见漫反射（UV-Vis DRS）、FESEM、TEM和BET测量仪对其进行了表征；采用可见光光源，甲醛（HCHO）液体为光催化反应模型物，研究了不同摩尔比下Ag₂O/ZnO复合光催化剂的暗吸附及光催化性能。结果表明，随着Ag₂O相对含量的增加，HCHO暗吸附效果出现先增大后减小的趋势，当Ag₂O与ZnO摩尔比为1∶5时，HCHO去除率达到43.34%；另一方面，在可见光下Ag₂O/ZnO复合光催化剂对HCHO的降解率呈先增大后减小的趋势，其中Ag₂O与ZnO的摩尔比为1∶10时取得最佳降解效果，经过90 min的可见光光照后HCHO降解率达到78%，总的HCHO去除率为85%。 

Fabrication of spong-like Ag2O/ZnO composite photocatalysts and photocatalytic degradation for formaldehyde under visible light irradiation

In order to overcome the disadvantage of low activity of the ZnO nanocrystals under visible light irradiation, the six square wurtzite spong-like ZnO nanocrystals were prepared by liquid phase co-precipitation thermal decomposition method with zinc nitrate hexahydrate, hexamethylene tetramine and oxalic acid dihydrate as the raw materials. The as-prepared spong-like ZnO were composited with Ag₂O nanocrystals under alkaline condition. The obtained Ag₂O/ZnO composite photocatalysts were characterized by XRD, FTIR, UV-Vis diffuse reflection spectroscopy (UV-Vis DRS), FESEM, TEM and BET analysis. The dark adsorption and photocatalytic acivity of the Ag₂O/ZnO composite photocatalysts with different mole ratios were investigated with formaldehyde (HCHO) as a degradation model using visible light source. The results indicate that with the increase of Ag₂O, the dark adsorption of HCHO increases first and then decreases with the maximum removal of 43.34% in which the mole ratio of Ag₂O to ZnO is 1:5. On the other hand, the best degradation effect is achieved when the mole ratio of Ag₂O to ZnO is 1:10, and the photodegradation of HCHO also increases first and then decreases under visible light with 78% photodegradation of HCHO and 85% of HCHO total removal after 90 min of visible light irradiation.