不同形貌Ag_3PO_4光催化过程热力学、动力学及表面热力学效应  

Thermodynamic properties, kinetic parameters and surface thermodynamic effect for photocatalytic process of Ag_3PO_4 with different morphologies

作　　者：刘作娇 范高超[1] 黄叶玲 覃小幸 黄在银[1,2,3] 谭学才[1,2,3] 钟莲云[1] 刘绍刚[1,2,3] 廖艳娟[1] 

机构地区：[1]广西民族大学化学化工学院,南宁530008 [2]广西林产化学与工程重点实验室,南宁530008 [3]广西高校食品安全与药物分析化学重点实验室,南宁530008

出　　处：《中国科学：化学》2015年第8期855-862,共8页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(20963001;21273050);广西高等学校高水平创新团队和卓越学者计划(桂教人[2014]7号)资助

摘　　要：室温条件下,采用离子交换法制备了四足状、立方体、十二面体和块体Ag3PO4.采用自主设计的新型光化学-微热量系统获取了LED白光下不同形貌Ag3PO4光催化降解甲基橙原位过程热力学和动力学信息,以此关联Ag3PO4的催化降解速率和催化机理.通过光量热系统外模拟实验证明Ag3PO4光催化活性规律,分别在405 nm激光和模拟日光下,对该规律进行了验证.利用微热量技术获取了不同形貌Ag3PO4的摩尔表面Gibbs自由能,并将其与催化活性相关联.结果表明,不同形貌Ag3PO4光催化活性由强到弱依次为立方体、四足状、十二面体和块体Ag3PO4,其光催化降解甲基橙原位过程的热效应分别为?885.63,?320.78,?238.5和?161.78 k J/mol;热焓变化率分别为?0.59,?0.21,?0.16和?0.11 mJ/s,该变化规律与催化降解速率具有一致性,Ag3PO4的表面结构和摩尔表面Gibbs自由能是导致其催化性能产生形貌效应的主要原因.Tetrapod, dodecahedrons, cubes and bulk Ag3PO4 were prepared by ion-exchange method at room temperature. The self-designed photo-microcalorimetry was used to obtain in-situ thermodynamic and kinetic information on the photocatalytic degradation process of methyl orange over Ag3PO4. Photocatalytic regularity of Ag3PO4 was explored by simulation experiments outside the system under LED light, and it was verified under the 405 nm laser and Xe lamp, respectively. The molar surface Gibbs free energy of Ag3PO4 was associated with the catalytic properties. The results showed that the catalytic activity order from high to low is in turn of cube, tetrapod, dodecahedrons and bulk Ag3PO4, and the corresponding thermal effects of the catalytic process were ？885.63, ？320.78, ？238.5 and ？161.78 k J/mol, and also the corresponding enthalpy change rate were ？0.59, ？0.21, ？0.16 and ？0.11 m J/s. The change rule was consistent with the catalytic degradation rate, and the morphology effect of photocatalysis was mainly attributed to surface structure and molar surface Gibbs free energy of Ag3PO4.

关 键 词：Ag3PO4 光催化 形貌效应 光量热计 表面热力学 

分 类 号：O621.251[理学—有机化学]