氮磷共掺杂TiO_2的制备、结构表征及高湿度下光催化净化氯苯废气的研究

Nitrogen and Phosphorus Co-Doped TiO_2 for Photocatalytic Removal of Gaseous Chlorobenzene under High Humidity Condition: Preparation, Characterization and Performance

以钛酸四丁酯为钛源、尿素为氮源、磷酸为磷源,采用溶胶凝胶-水热法制备了氮磷共掺杂TiO_2光催化剂,用于高湿度氯苯(Chlorobenzene,CB)废气的净化。通过响应面法确定了最佳制备比例,N、P、(NH_4)_2CO_3与Ti的物质的量比为0.5:0.5:0.5:1。利用XRD、TEM和XPS等方法对催化剂进行表征,氮磷共掺杂TiO_2为锐钛矿和金红石混合晶型,具有较大的比表面积,吸收波长红移至497 nm。在相对湿度10%、CB初始进气浓度150 mg·m^(-3)、停留时间60s时,CB去除率达到94.6%;该催化剂的光催化活性随着相对湿度的增加下降非常缓慢,在相对湿度90%时仍可获得较高的CB转化率(>70%);催化剂连续使用24 h后,对CB的催化转化率从94%降至74%,表明催化性能稳定性较好。

Nitrogen and phosphorus co-doped TiO_2 photocatalysts were synthesized by a hydrothermal sol-gel method using tetrabutyl titanate as titanium source, urea as nitrogen source and phosphoric acid as phosphorus source. Response surface methodology（RSM） was employed to obtain the optimum ratio of 0.5：0.5：0.5：1（N：P：（NH_4）_2CO_3：Ti） for achieving the best chlorobenzene（CB） removal rate. The catalysts were characterized by XRD, TEM, XPS, etc., and the results suggest that the nitrogen and phosphorus co-doped TiO_2 consists of anatase and rutile with larger surface area. The UV-vis absorption spectra are red-shifted to 497 nm. CB removal efficiency is 94.6% under conditions of relative humidity 10%, initial concentration 150 mg·m^（-3） and residence time 60 s. The catalyst remains high removal efficiency（over 70%） under relative humidity 90%, and the removal efficiency decreases slowly under high relative humidity. The catalytic activity slightly reduces from 94% to 74% after continuous running for over 24 h, which reveals that the prepared catalyst has good stability.