二氧化钛@聚二乙烯基苯Janus颗粒的Pickering效应及其非均相光催化降解性能

Heterogeneous Photocatalytic Degradation under the Pickering Effect of TiO_(2)@PDVB Janus Particles

催化剂与反应介质的碰撞是其发挥催化作用、降低反应活化能的基础.在非均相催化反应中,由于界面十分有限,催化剂催化效率较低.利用溶胀突出聚合技术制备了二氧化钛@聚二乙烯基苯(silica@polydivinylbenzene, TiO2@PDVB)Janus颗粒并应用于硝基苯的光催化降解.采用扫描电镜、接触角测试和比表面积测试分析TiO2@PDVB Janus颗粒的微观形貌和化学组成,观察在Janus颗粒作用下,硝基苯紫外吸收强度的变化.结果表明,各向异性的TiO2@PDVB Janus颗粒具有Pickering效应,在油水界面上定向排列以稳定乳液,并为两相液体在界面上的迁移提供通道,因此反应物和催化剂之间的接触概率大大增加.尽管TiO2@PDVB Janus颗粒的粒径比各向同性的P25 TiO2颗粒大10倍以上,但其对硝基苯的降解效率比TiO2高5.6%,且兼具稳定乳液和异相催化的Janus颗粒回收和活化均十分方便,有望应用于工业催化.

The collision between catalyst and reaction medium is the basis for its catalytic effect and reduction of reaction activation energy.The heterogeneous catalytic efficiency is low due to a small oil-water interface.Herein,TiO_(2)@PDVB Janus particles synthesized by polymerization after swelling-protruded were used in the photocatalysis degradation of nitrobenzene.The microscopic mor-phology and chemical composition of TiO_(2)@PDVB Janus particles were studied by scanning electron microscopy,contact angle testing,and specific surface area testing.Additionally,the change in the ultraviolet absorption intensity of nitrobenzene in response to the Janus particles was observed.The results showed that the anisotropic TiO_(2)@PDVB Janus particles exhibited Pickering effect.They were arranged directionally at the interface to stabilize emulsion and provide channels for liquid migration,increasing the contact probability between reactants and catalysts.Compared with iso-tropic P25 TiO_(2) particles,TiO_(2)@PDVB Janus particles showed a 5.6%higher degradation rate of nitrobenzene although their size was more than ten times larger.Moreover,the recovery and activa-tion of Janus particles with both stabilization and heterogeneous catalysis are very convenient.Janus materials are expected to be applied in industrial catalysis.