微波液相法一步合成 H3PW12O40/Bi2WO6光催化剂及其脱氮性能

One-step Preparation of H_3PW_(12)O_(40)/Bi_2WO_6 Nano-photocatalysts by Microwave Liquid Process and Its Photocatalysis Denitrification Properties

采用微波液相法一步合成了固载型H3PW12O40/Bi2WO6光催化剂.通过紫外-可见漫反射光谱(UV-Vis)、场发射扫描电子显微镜(SEM)、表面积及孔隙度(BET)测定、氨气程序升温脱附(NH3-TPD)、吡啶吸附红外光谱(Py-FTIR)和X射线衍射(XRD)对所合成催化剂的结构和性质进行了考察,并以吡啶浓度为15 mg/g的模拟油对光催化剂的脱氮效果进行评价.结果表明,与传统浸渍固载法相比,微波液相一步法不仅能高效合成H3PW12O40/Bi2WO6光催化剂,且所合成的催化剂能被低能量的光激发.固载H3PW12O40不但能提高Bi2WO6纳米颗粒的表面酸量,还能通过改变Bi2WO6前驱液的酸强度来调控催化剂形貌.在H3PW12O40固载量为15%(质量分数),微波功率为800 W,反应时间为90 min条件下得到的H3PW12O40/Bi2WO6的光催化脱氮活性最高,在催化剂与模拟油质量比为1/300,500 W氙灯光照60 min的最佳光催化反应条件下,模拟油脱氮率达到92.63%.

Immobilized nano-photocatalysts H3 PW12 O40 / Bi2 WO6 was prepared by microwave liquid one-step process. The morphology, structure and properties of the prepared catalysts were characterized and investiga-ted by UV-Vis diffuse reflectance spectra, scanning electron microscopy（SEM）, NH3 temperature programmed desorption（ NH3-TPD）, pyridine adsorption Fourier transform infrared spectroscopy （ Py-FTIR） and X-ray diffraction（XRD）, respectively. Their photocatalytic denitrification properties were evaluated by using the model oil with 15 mg / g pyridine. The results show that H3 PW12 O40 / Bi2 WO6 photocatalysts could be more effi-ciently synthesized by microwave liquid one-step process, and it could be excited by lower photon energy than that synthesized by common impregnation immobilization method. Immobilization of H3 PW12 O40 on Bi2 WO6 could improve the acid content in Bi2 WO6 nanoparticle surface, change the acid strength of Bi2 WO6 precursor solution thereby controll the catalyst morphology. The influences of preparation conditions on photocatalytic properties of H3 PW12 O40 / Bi2 WO6 were investigated. It was found that H3 PW12 O40 / Bi2 WO6 nano-photocata-lyst, with the H3 PW12 O40 loading（mass fraction） of 15% , prepared by microwave liquid one-step process un-der microwave power 800 W for 90 min possessed the best performance in the photocatalytic denitrification of model oil containing photocatalysts（ mass ratio of catalyst to model oil was 1 / 300） after 500 W Xe lamp irradiation for 60 min, with the denitrification rate reached 92. 63% .