CAJ | 학술논문

基于微波水热法和微乳液法合成SnO2/TiO2纳米管复合光催化剂.通过X射线衍射(XRD)、配有能量色散X射线光谱仪(EDX)的透射电镜(TEM)和电化学手段对光催化剂进行表征.以甲苯为模型污染物,考察光催化剂在紫外光(UV)和真空远紫外光(VUV)下的性能及失活再生.结果表明, SnO2/TiO2纳米管复合光催化剂形成三元异质结(锐钛矿相TiO2(A-TiO2)/金红石相TiO2(R-TiO2)、A-TiO2/SnO2和R-TiO2/SnO2异质结),促使光生电子-空穴对的有效分离,提高光催化活性. SnO2/TiO2表现出最佳的光催化性能, UV和VUV条件下的甲苯降解率均达100%, CO2生成速率(k2)均为P25的3倍左右.但由于UV光照矿化能力不足,中间产物易在催化剂表面累积.随着UV光照时间的增加, SnO2/TiO2逐渐失活,20 h后k2由138.5 mg?m-3?h-1下降到76.1 mg?m-3?h-1.利用VUV再生失活的SnO2/TiO2,过程中产生的?OH、O2-?、O(1D)、O(3P)、O3等活性物质可氧化吸附于催化剂活性位的难降解中间产物,使催化剂得以再生,12 h后k2恢复到143.6 mg?m-3?h-1. UV和VUV的协同效应使UV降解耦合VUV再生成为一种可持续的光催化降解污染物模式.
기우미파수열법화미유액법합성SnO2/TiO2납미관복합광최화제.통과X사선연사(XRD)、배유능량색산X사선광보의(EDX)적투사전경(TEM)화전화학수단대광최화제진행표정.이갑분위모형오염물,고찰광최화제재자외광(UV)화진공원자외광(VUV)하적성능급실활재생.결과표명, SnO2/TiO2납미관복합광최화제형성삼원이질결(예태광상TiO2(A-TiO2)/금홍석상TiO2(R-TiO2)、A-TiO2/SnO2화R-TiO2/SnO2이질결),촉사광생전자-공혈대적유효분리,제고광최화활성. SnO2/TiO2표현출최가적광최화성능, UV화VUV조건하적갑분강해솔균체100%, CO2생성속솔(k2)균위P25적3배좌우.단유우UV광조광화능력불족,중간산물역재최화제표면루적.수착UV광조시간적증가, SnO2/TiO2축점실활,20 h후k2유138.5 mg?m-3?h-1하강도76.1 mg?m-3?h-1.이용VUV재생실활적SnO2/TiO2,과정중산생적?OH、O2-?、O(1D)、O(3P)、O3등활성물질가양화흡부우최화제활성위적난강해중간산물,사최화제득이재생,12 h후k2회복도143.6 mg?m-3?h-1. UV화VUV적협동효응사UV강해우합VUV재생성위일충가지속적광최화강해오염물모식.
SnO2/TiO2 nanotube composite photocatalysts were synthesized by microwave-assisted hydrothermal and micro-emulsion methods. The photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM/EDX), and electrochemical techniques. Toluene was chosen as a model pol utant to evaluate the performance, deactivation, and regeneration behavior of the photocatalysts under ultraviolet (UV) and vacuum ultraviolet (VUV) irradiation. The results show that ternary heterojunctions of SnO2/TiO2 nanotube composite photocatalysts including anatase TiO2 (A-TiO2)/rutile TiO2 (R-TiO2), A-TiO2/SnO2, and R-TiO2/SnO2 were successful y created. They were able to separate photogenerated electron-hole pairs efficiently, and promote photocatalytic activity accordingly. SnO2/TiO2 showed the best photocatalytic performance. Under UV or VUV irradiation, the toluene degradation rate of SnO2/TiO2 was 100%, and the CO2 formation rate (k2) of SnO2/TiO2 was approximately 3 times higher than that of P25. Because of the low mineralization rate under UV irradiation, the refractory intermediates generated can occupy active photocatalytic sites on the photocatalyst surface, which hinders the photocatalytic oxidation rate. After 20 h of UV irradiation, the k2 of SnO2/TiO2 decreased from 138.5 to 76.1 mg?m-3?h-1, implying that the photocatalysts can be deactivated quickly. VUV irradiation was employed to regenerate the deactivated SnO2/TiO2 because reactive species such as?OH, O2-?, O(1D), O(3P), and O3 can be generated. These play an important role in the oxidation of refractory intermediates on the photocatalyst surface, and k2 increased to 143.6 mg?m-3?h-1 accordingly. Therefore, UV photodegradation combined with VUV regeneration could be a feasible photocatalytic process because of a synergistic effect between UV and VUV.