Ag^+/ZnO纳米晶的制备及对亚甲基蓝的异相光催化行为

Synthesis of Ag^+/ZnO coupled nanoparticles and their heterogeneous photocatalysis of MB in aqueous suspension

以水合碳酸锌为前驱体利用激光复合加热蒸发技术制得平均粒径在20nm左右的Ag+掺杂ZnO纳米晶半导体光催化剂系列.用XRD、UV-Vis、TEM、PL等手段对纳米晶进行了表征,结果表明掺杂Ag+有助于ZnO对可见光的吸收,ZnO纳米晶为四针形,而掺杂产物为球形.在悬浮Ag+掺杂ZnO纳米晶的悬浮水相体系中,通过脱色率、紫外-可见吸收光谱和COD值的测定证实了Ag+掺杂有效的改善了ZnO对亚甲基蓝(MB)的光催化降解性能.探讨了几种因素对MB降解率的影响,当pH为12.0、C0为30mg·L-1、催化剂为2.5mg·L-1时,30min其脱色率达98.98%,COD的去除率达85.10%.

Series of semiconductor-assisted photocatalysts of Ag^+-doped ZnO nanocrystals were synthesized by laser-induction complex heating technique from the precursor of Zn_5(CO_3)_2(OH)_6. The photo-activity and photochemical degradation were characterized by applying TEM,XRD,UV-Vis,PL, et al. The average particles' sizes are 20 nm. Above all, photodegradation activities of methylene blue (MB) on doped or undoped nanoparticles in aqueous suspensions were investigated. After 30 min, UV irradiation (λ>254 nm), the concentration of MB solution was 30 mg/L with 2.0 mol% Ag^+-doped ZnO nanocrystals 2.5 g/L, the removal efficiency of MB was 98.98%, and the COD also decreased 85.10%. The influence of various parameters was discussed.