| Title: | The remarkable effect of alkali earth metal ion on the catalytic activity of OMS-2 for benzene oxidation |
| Author(s): | Ni C; Hou J; Li L; Li Y; Wang M; Yin H; Tan W; |
| Address: | "College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China. College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China. Electronic address: houjt87@163.com. State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China" |
| DOI: | 10.1016/j.chemosphere.2020.126211 |
| ISSN/ISBN: | 1879-1298 (Electronic) 0045-6535 (Linking) |
| Abstract: | "Cryptomelane-type octahedral molecular sieve (OMS-2) is one of the most promising catalysts for VOCs oxidation, and introduction of metal ions in OMS-2 tunnel is widely used for tailoring its catalytic activity. Here, different types of alkali earth metal ions with the same X/Mn atomic ratio of approximately 0.012 (X represents Mg(2+), Ca(2+), and Sr(2+)) were successfully introduced into OMS-2 tunnel by a one-step redox reaction. The catalytic test showed that introducing alkali earth metal ions into tunnels had a considerable effect on the catalytic performance of OMS-2 for benzene oxidation. The Sr(2+) doped OMS-2 catalyst exhibited the better catalytic activity compared with those of Mg-OMS-2 and Ca-OMS-2 samples, and was also superior to a commercial 0.5% Pt/Al(2)O(3) catalyst, as evidenced by its low reaction temperatures of T(50) = 200 degrees C and T(90) = 223 degrees C (corresponding to benzene conversions at 50% and 90%, respectively). The origin of the considerable effect of alkali earth metal doping on the catalytic activity of OMS-2 catalysts was experimentally and theoretically investigated by an (18)O(2) isotopic labeling experiment, CO temperature-programmed reduction, O(2) temperature-programmed oxidation, and density functional theory calculations. The greatest catalytic activity of Sr-OMS-2 compared with those of Mg-OMS-2 and Ca-OMS-2 samples was attributed to its highest lattice oxygen activity as well as its largest surface area. By introducing alkali earth metal ions into the OMS-2 tunnel, we developed a low-cost and highly efficient catalyst that could be used as alternative to noble metal catalysts" |
| Keywords: | "Alkalies Benzene/*chemistry Catalysis Cyclohexanes Ions Metals, Alkaline Earth/*chemistry *Models, Chemical Oxidation-Reduction Oxygen Temperature Alkali earth metal ions Catalytic oxidation Oms-2 Substitution Volatile organic compounds;" |
| Notes: | "MedlineNi, Chunlan Hou, Jingtao Li, Lei Li, Yuanzhi Wang, Mingxia Yin, Hui Tan, Wenfeng eng England 2020/03/01 Chemosphere. 2020 Jul; 250:126211. doi: 10.1016/j.chemosphere.2020.126211. Epub 2020 Feb 22" |
