Efficient Elimination of Chlorinated Organics on a Phosphoric Acid Modified CeO2 Catalyst: A Hydrolytic Destruction Route

Autor: Xiaoxia Dai, David J. Morgan, Yunpeng Long, Stuart Hamilton Taylor, Graham J. Hutchings, Yunhao Lu, Xinwei Wang, Zhongbiao Wu, James H. Carter, Xiaole Weng, Samuel Pattisson
Rok vydání: 2019
Předmět:
Zdroj: Environmental Science & Technology. 53:12697-12705
ISSN: 1520-5851
0013-936X
DOI: 10.1021/acs.est.9b05088
Popis: The development of efficient technologies to prevent the emission of hazardous chlorinated organics from industrial sources without forming harmful by-products, such as dioxins, is a major challenge in environmental chemistry. Herein, we developed a new hydrolytic destruction route for efficient chlorinated organics elimination and demonstrated that phosphoric acid modified CeO2 (HP-CeO2) can hydrolytically destruct chlorobenzene (CB) without forming polychlorinated congeners under the industry-relevant reaction conditions. The active site and origin of hydrolysis reactivity of HP-CeO2 were probed, which showed the surface phosphate groups can hydrolytically react with CB and water to form phenol and HCl, thus facilitating the chlorine desorption and ensuring a continual O2 activation. Subsequent density functional theory (DFT) calculations revealed a distinctly decreased formation energy of oxygen vacancy nearest (VO-1) and next-nearest (VO-2) to the bonded phosphate groups, which led to a significantly improved oxidizing ability of the catalyst. Significantly, no toxic dioxins were detected from the hydrolysis destruction of CB, which has been frequently cited as a significant challenge to avoid in the conventional oxidation route. This work not only reports an efficient route and corresponding phosphate active site for chlorinated organics elimination, but also illustrates that rational design of reaction route can solve some of the most important challenges in environmental catalysis.
Databáze: OpenAIRE