Urea-H2O2 defect engineering of δ-MnO2 for propane photothermal oxidation: Structure-activity relationship and synergetic mechanism determination

• Published in: Journal of colloid and interface science Vol. 641; pp. 48 - 58
• Main Authors: Feng, Chao, Bi, Yuxi, Chen, Chong, Li, Shuangju, Wang, Zhong, Xin, Hongchuan, Pan, Yuan, Liu, Fang, Lu, Yukun, Liu, Yunqi, Zhang, Runduo, Li, Xuebing
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.07.2023
• Subjects: Defect engineering; Photothermal catalysis; Propane oxidation; Reaction mechanism; δ-MnO2; Reaction mechanism; Defect engineering; Photothermal catalysis; δ-MnO2; Propane oxidation
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.03.052

[Display omitted] •MnO2 treated by urea-H2O2 exhibits great photocatalytic propane oxidation activity.•H2O2 treatment increase active sites to thermal catalytic performance.•The photocatalytic performance improvement is related to photogenerated electrons.•A new photothermal synergetic catalysis mechanism was proposed. Photothermal catalysis has an advantage in effective and economical elimination technology of volatile organic compounds (VOCs) in the ascendant. Herein, various surface defect engineering routes were adopted to enhance the low-temperature propane oxidation of δ-MnO2. Compared to reducing etchants urea and vitamin C, δ-MnO2 treated with urea - H2O2 exhibited an excellent thermal (T90 = 240 ℃) and photothermal (T90 = 196 ℃) activities of propane oxidation. Urea - H2O2 treatment provided high concentration of Mn4+ and surface-active oxygen (Mn4+-Osur) species as surface-active sites, and produced numerous oxygen vacancies to improve charge separation and superoxide species generation capacity. Thus, the photothermal conversion efficiency and low-temperature reducibility were remarkably enhanced. Furthermore, the photothermal synergistic catalytic mechanism was proposed based on in-situ diffuse reflectance infrared Fourier transform spectroscopy and control experiments. The strategy here offered insight into the rational design of efficient transition catalysts, and in-depth understanding of the photothermal catalytic VOCs removal mechanism.