Highly Efficient Catalytic Ozonization at Ultralow Temperatures of Multicomponent VOCs over the Pt/CeO<sub>2</sub> Catalysts
Jia Wang, Yuxi Liu, Jiguang Deng, Lin Jing, Xiuqing Hao, Ruyi Gao, Hongxing Dai
Abstract
Industrial flue gas has a great impact on the atmosphere environment and human health, and its emission temperatures are usually below 180 °C, which needs a new technology that can catalyze the removal of the multicomponent VOCs over high-performance catalysts in the presence of ozone. In this work, we prepared the Pt/CeO 2 catalysts with different morphologies of Pt particles and investigated their catalytic performance for the ozonization of mixed VOCs (i.e., toluene and chlorobenzene (CB)). Among all of the as-prepared samples, Pt NRs/CeO 2 with nanorod-like Pt particles showed excellent catalytic performance for the ozonization of toluene and CB. The T 50% (the temperature at VOC conversion = 50%) values for toluene and CB ozonization were 40 and 48 °C at a space velocity of 40,000 mL g –1 h –1, respectively. The results of characterization revealed that the reactive oxygen species involved in the VOC ozonization were mainly the O 2 – and O 2 2– species, surface oxygen vacancies of CeO 2 were the active sites for the conversion of ozone to the reactive oxygen species, and the O 2 – species was the mainly active oxygen species in the low-temperature VOC oxidation. Furthermore, partial reactive oxygen species reacted with the Pt n + species to generate more amount of the Pt 0 species, and the metallic platinum species was the main active site for the adsorption and activation of toluene and CB. The chemisorbed VOCs at the Pt 0 sites reacted with the reactive oxygen species at the interface of Pt and CeO 2, resulting in the excellent low-temperature catalytic activity. Compared with the reaction without ozone participation, we find that the participation of ozone can not only decrease the reaction temperature but also reduce the production of toxic byproducts. We are sure that the Pt/CeO 2 catalyst is promising in practical application for elimination of the VOCs from industrial flue gas.