g-C3N4@Ag3PO4光催化降解罗丹明B过程的原位光-微热量-荧光光谱研究  

In-situ Photocatalytic Process of Rhodamine B over g-C_3N_4@Ag_3PO_4 Nanocomposites Based on Photomicrocalorimeter-fluorescence Spectrometry

作　　者：万婷 李星星 黄在银 邱江源 左晨 谭学才 

机构地区：[1]广西民族大学化学化工学院 [2]广西高校食品药品安全与药物分析化学重点实验室,南宁530006

出　　处：《高等学校化学学报》2017年第12期2226-2230,共5页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21273050,21573048);广西民族大学研究生教育创新计划项目(批准号:gxun-chxps201681,gxun-chxzs2016121)资助

摘　　要：采用光-微热量-荧光光谱联用系统获取了g-C_3N_4@Ag_3PO_4光降解罗丹明B(RhB)的原位热/动力学信息和三维荧光光谱信息,并结合热力学和光谱学结果探究了光催化降解罗丹明B的微观机制.结果表明,光催化降解过程主要分为表观吸热、热平衡以及稳定放热3个阶段.在g-C_3N_4@Ag_3PO_4存在下,可见光照射10 min后,罗丹明B的三维荧光特征发射峰强度降低至初始值的7.1%,罗丹明B的降解脱色率达92.9%,是相同条件下以纯g-C_3N_4为催化剂时的2.06倍.随着光照时间的延长,光-微热量计显示10 min后以降解及矿化非荧光中间产物为主,并保持热焓变化率为-(0.226±0.0916)mJ/s稳定放热,为拟零级反应过程,并且该阶段为光催化反应的决速步骤.A photomicrocalorimeter-fluorescence spectrometer was applied to obtain in-situ thermodynamics,kinetics and 3D fluorescence spectra of Rhodamine B photocatalysis over g-C_3N_4@Ag_3PO_4 nanocomposites.And its mechanism was investigated by coupling the thermodynamics and its spectroscopic information.Consequently,the whole process underwent an initial endothermic reaction and a subsequent exothermic stage,and finally maintained a stable exothermic platform.The intensity of fluorescence emission peak of Rhodamine B over g-C_3N_4@Ag_3PO_4 decreased sharply within the illumination of 10 min,its degradation rate reached 92.9%,which was 2.06 times that over g-C_3N_4.Subsequently,the photodegradation of the ring and intermediates without fluorescent chromophores were dominated,which maintained a stable exothermic rate of -（0.226±0.0916） m J/s with a pseudo-zero order process.This process was the rate-determining step.Therefore,Rhodamine B photocatalysis was a pseudo-zero-order process rather than a first order process.

关 键 词：光催化 g-C3N4@Ag3PO4 光-微热量计 原位荧光光谱 热动力学 

分 类 号：O645[理学—物理化学]