Shi Zhan, Dong Fang, Han Weiliang, Dong Xiuyan, Tang Zhicheng
School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
State Key Laboratory for Oxo Synthesis and Selective Oxidation, and National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
Nanoscale. 2024 Jun 6;16(22):10760-10778. doi: 10.1039/d4nr00806e.
Sulfur dioxide poisoning is a significant factor in catalyst deactivation during the catalytic combustion of volatile organic compounds. In this study, we prepared the LaCoO and CoO composite catalysts using both the Ship-in-Bottle and Building-Bottle-Around-Ship approaches. Three-dimensionally ordered macropores (3DOM LaCoO) were utilized as nanoreactors to protect the active sites during the catalytic combustion of toluene, preventing SO poisoning. Additionally, we grew ZIF-67 confined in the nanoreactor to create a multistage-pore structure. The CoO@3DOM LaCoO catalysts exhibited excellent activity in the complete catalytic oxidation of toluene. Various characterization studies confirmed the presence of a significant number of Co species and an abundance of surface weak acid sites in the CoO@3DOM LaCoO catalysts, which synergistically enhanced the conversion of VOCs at low temperatures. Notably, the multistage pore structure provided a favorable reaction environment, accelerating the adsorption and diffusion of toluene and intermediates, resulting in excellent sulfur resistance of the catalysts. Moreover, XPS analysis confirmed a strong interaction between CoO and LaCoO, promoting rapid electron transfer and increasing the activation of O. DRIFTS experiments verified that toluene mainly follows the MvK mechanism over CoO@3DOM LaCoO catalysts, indicating the following reaction pathway: toluene adsorption → benzyl alcohol → benzaldehyde → benzoate → anhydride → CO and HO.
二氧化硫中毒是挥发性有机化合物催化燃烧过程中催化剂失活的一个重要因素。在本研究中，我们采用瓶中造船法和绕船造瓶法制备了LaCoO和CoO复合催化剂。利用三维有序大孔（3DOM LaCoO）作为纳米反应器，在甲苯催化燃烧过程中保护活性位点，防止SO中毒。此外，我们在纳米反应器中生长了受限的ZIF-67，以创建多级孔结构。CoO@3DOM LaCoO催化剂在甲苯的完全催化氧化中表现出优异的活性。各种表征研究证实，CoO@3DOM LaCoO催化剂中存在大量的Co物种和丰富的表面弱酸位点，它们协同增强了低温下VOCs的转化。值得注意的是，多级孔结构提供了良好的反应环境，加速了甲苯和中间体的吸附和扩散，导致催化剂具有优异的抗硫性。此外，XPS分析证实了CoO与LaCoO之间存在强相互作用，促进了快速电子转移并增加了O的活化。DRIFTS实验证实，甲苯在CoO@3DOM LaCoO催化剂上主要遵循MvK机理，表明其反应途径如下：甲苯吸附→苯甲醇→苯甲醛→苯甲酸盐→酸酐→CO和HO。
