光量热法初探甲基橙光催化原位降解过程

通过在室温下还原前驱体制备了Ag@AgCl催化剂, 并利用X射线粉末衍射仪(XRD)和场发射扫描电子显微镜(FE-SEM)对产物进行表征. 设计了新型光化学-微热量系统, 用该系统获得了Ag@AgCl光催化降解甲基橙实时、 在线的热力学和动力学瞬态信息. 研究结果表明, 该降解过程首先经历吸热再迅速进入放热阶段, 最后曲线恒定于一个长的放热平台, 计算得到ab, ac和ad段的热效应分别为-0.2609, 2.5845和40.7289 J, 放热平台cd的平均速率为2.581 mJ/s, 并详细探讨了该过程的微观降解机制.

Primary Photocalorimetry Investigation of the In-situ Photocatalytic Process of Methyl Orange Degradation†

Ag@AgCl photocatalyst was prepared by reduction of AgCl precursor at room temperature, and characterised by X-ray powder diffraction(XRD) and field-emission scanning electron microscope(FE-SEM). A novel photoreaction-microcalorimetry was designed and employed to obtain the on-line thermodynamic and kinetic informations of photocatalysis of methyl orange over Ag@AgCl. The results showed that the degradation process went through an initial endothermic reaction and followed by an exothermic stage which finally kept a constant exothermic rate for at least 4 h. The heat effects of ab, ac, and ad stages were -0.2609, 2.5845 and 40.7289 J, respectively. Meanwhile, the steady rate of exothermic platform, the stage of cd, is 2.581 mJ/s. The microscopic mechanism of photodegradation was discussed in detail.