Catalytic Oxidation of Chlorinated Organics over Lanthanide Perovskites: Effects of Phosphoric Acid Etching and Water Vapor on Chlorine Desorption Behavior

作者：Xiaole Weng, Qingjie Meng, Jiajia Liu, Weiyu Jiang, Samuel Pattisson, Zhongbiao Wu · 发表于：Environmental Science & Technology · 年份：2018 · DOI：10.1021/acs.est.8b04582 · 被引用次数：250 · 研究领域：Catalytic Processes in Materials Science、Catalysis and Oxidation Reactions、Environmental remediation with nanomaterials

In this article, the underlying effect of phosphoric acid etching and additional water vapor on chlorine desorption behavior over a model catalyst La 3 Mn 2 O 7 was explored. Acid treatment led to the formation of LaPO 4 and enhanced the mobility of lattice oxygen of La 3 Mn 2 O 7 evidenced by a range of characterization (i.e., X-ray diffraction, temperature-programmed analyses, NH 3 –IR, etc.). The former introduced thermally stable Brönsted acidic sites that enhanced dichloromethane (DCM) hydrolysis while the latter facilitated desorption of accumulated chlorine at elevated temperatures. The acid-modified catalyst displayed a superior catalytic activity in DCM oxidation compared to the untreated sample, which was ascribed to the abundance of proton donors and Mn(IV) species. The addition of water vapor to the reaction favored the formation and desorption of HCl and avoided surface chlorination at low temperatures. This resulted in a further reduction in reaction temperature under humid conditions ( T 90 of 380 °C for the modified catalyst). These results provide an in-depth interpretation of chlorine desorption behavior for DCM oxidation, which should aid the future design of industrial catalysts for the durable catalytic combustion of chlorinated organics.