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室温下用葡萄糖还原前驱体AgCl制备了可见光驱动的表面负载Ag纳米颗粒(NPs)催化剂Ag@AgCl,并采用X射线衍射(XRD)、场发射扫描电镜(FE-SEM)对其形貌、组成和结构进行了表征.首次运用自主设计的新型光化学-微量热系统,获取了三个功率光催化降解甲基橙的原位特征热谱曲线和原位热动力学精细信息,并与紫外-可见光谱获得的动力学信息关联,结合甲基橙逐步被氧化降解的特征,讨论了光催化降解机理.结果表明:光催化降解过程首先是偶氮双键在光的作用下迅速吸热断裂,再进入氧化降解中间产物的放热阶段,最后以恒定的速率长时间放热.光催化反应主要受光功率大小、粒子的传质以及活性氧化物种产生的速率等共同影响.随着光功率减小,光催化反应速率减缓,体系热效应的特征变化出现滞后现象,达到最大吸、放热峰及甲基橙完全降解所需时间延长.
Ag @ AgCl, a visible-light-driven surface-loaded Ag nanoparticle (NPs) catalyst, was prepared at room temperature using glucose reduction precursor AgCl. The morphology and composition of Ag @ AgCl were characterized by X-ray diffraction and field emission scanning electron microscopy. And the structure were characterized.Using the newly designed photochemical-micro calorimeter system, three in-situ photocatalytic degradation of methyl orange in situ thermal spectroscopy curve and in-situ thermodynamic detailed information were obtained and compared with UV-visible The kinetic information of spectra was obtained and the mechanism of photocatalytic degradation of methyl orange was gradually discussed. The photocatalytic degradation mechanism was discussed. The results showed that the photocatalytic degradation process was initiated by the rapid thermal endothermic cleavage of the azo double bond under the action of light Enter the exothermic stage of oxidative degradation intermediate products, and finally radiate for a long time at a constant rate.The photocatalytic reaction is mainly affected by the optical power, the mass transfer of particles and the generation rate of reactive oxygen species, etc. As the optical power decreases, The photocatalytic reaction rate slowed down, and the characteristic changes of the system thermal effect appeared hysteresis, reaching the maximum absorption and exothermic peak and the time required for complete degradation of methyl orange.