空心板栗状MAPbI_(3)/TiO_(2)的制备及可见光下降解甲苯研究

Preparation of hollow chestnut MAPbI_(3)/TiO_(2)for visible light catalytic degradation of toluene

首先,以TiCl_(4)为钛源,采用水热法制备空心板栗状TiO_(2)载体.然后,再以PbI_(2)及MAI(MA=CH_(3)NH_(3)^(+))为前驱体,采用溶液法在空心板栗状TiO_(2)上一步构筑MAPbI_(3)薄膜,形成空心板栗状MAPbI_(3)/TiO_(2)复合光催化剂.以甲苯为目标降解物,考察板栗状MAPbI_(3)/TiO_(2)在可见光下的催化降解性能,并对材料的能级结构进行分析,揭示材料的降解机理.结果表明:钙钛矿型MAPbI_(3)薄膜的组成及形貌与PbI_(2)和MAI投料比密切相关,随着投料比的增加,薄膜的成分由MAPbI_(3)和MAI两相变为纯MAPbI_(3),再转变MAPbI_(3)和PbI_(2)两相.能级匹配、结构特殊的板栗状MAPbI_(3)/TiO_(2)不仅可以降低光生电子和空穴的复合率,还能有效地将光生电子和空穴分别转移至MAPbI_(3)的导带及TiO_(2)价带,促进活性粒子·O_(2)^(-)和·OH的生成,因此在甲苯的降解中表现更优的性能.在可见光的照射下,MAPbI_(3)/TiO_(2)对甲苯的降解率在90 min内可高达98%.

Firstly,hollow chestnut TiO_(2)carrier was prepared by hydrothermal method with TiCl_(4) as titanium source.Then,using PbI_(2) and MAI as precursors,MAPbI_(3)thin films were constructed on hollow chestnut TiO_(2)by solution method to form hollow chestnut MAPbI_(3)/TiO_(2)composite photocatalyst.Taking toluene as the target degradation material,the catalytic degradation performance of chestnut MAPbI_(3)/TiO_(2)composite photocatalyst under visible light was investigated,and the energy level structure of the material was analyzed to reveal the degradation mechanism of the material.The results show that the composition and morphology of perovskite MAPbI_(3)thin films are closely related to the feed ratio of PbI_(2) and MAI.With the increase of feed ratio of PbI_(2),the composition of the thin films changes from MAPbI_(3)and MAI to pure MAPbI_(3)and then to MAPbI_(3)and PbI_(2).The chestnut MAPbI_(3)/TiO_(2)with matched energy level and special structure can not only reduce the recombination rate of photogenerated electrons and holes,but also effectively transfer the photogenerated electrons and holes to the conduction band of MAPbI_(3)and TiO_(2)valence band respectively,promoting the generation of active particles·O_(2)^(−)and·OH,so it has better performance in the degradation of toluene.Under the irradiation of visible light,the degradation rate of MAPbI_(3)/TiO_(2)was up to 98%in 90 min.