College of Science, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, P. R. China.
Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States.
Anal Chem. 2020 Jul 21;92(14):9989-9996. doi: 10.1021/acs.analchem.0c01668. Epub 2020 Jul 6.
In situ monitoring of products generated by important heterogeneous catalytic reactions is of great significance for chemical industry, particularly when the products or intermediates are not sufficiently stable or occur at trace-level concentrations. It is therefore highly desirable to develop an integrated in situ catalysis and extraction method, which can simultaneously catalyze the reaction and enrich products while maintaining compatibility with analytical instrumentation. Herein, we propose an approach by depositing different types of metal nanocrystals, including gold, platinum, and palladium nanoparticles, onto fibrous silica microspheres coated fibers for integrated in situ catalysis and extraction. As a proof-of-concept, several typical chemical reactions, including the reduction of -nitrophenol, epoxidation of styrene, oxidation of benzyl alcohol, and dechlorination of -chlorophenol, were investigated to validate the feasibility of this method. Our results show that these coatings not only function as catalysts to accelerate the selected reactions but also serve as adsorbents to extract the reactants, intermediates, and products for direct gas chromatographic analysis, suggesting the viability of this approach for the in situ evaluation of catalytic processes. By this approach, the yield, selectivity, and kinetics of a reaction can be readily assessed. This approach can also be extended to investigate the catalytic performance of the same metal nanocrystals with different morphology, surface facet, structure, or surface functionalization. This approach will find broad generality for assessing the catalytic efficiency and selectivity of new catalysts or new chemical reactions and dynamic processes in these reactions.
原位监测重要多相催化反应生成的产物对于化学工业具有重要意义，特别是当产物或中间体不够稳定或痕量存在时。因此，开发一种集成的原位催化和萃取方法非常重要，该方法可以在保持与分析仪器兼容性的同时，同时催化反应和富集产物。在此，我们提出了一种方法，即将不同类型的金属纳米晶体（包括金、铂和钯纳米粒子）沉积到涂覆纤维的纤维状硅微球上，用于集成的原位催化和萃取。作为概念验证，我们研究了几种典型的化学反应，包括-硝基苯酚的还原、苯乙烯的环氧化、苯甲醇的氧化和-氯苯酚的脱氯，以验证该方法的可行性。结果表明，这些涂层不仅可以作为催化剂来加速所选反应，还可以作为吸附剂来提取反应物、中间产物和产物，以直接进行气相色谱分析，这表明该方法适用于原位评估催化过程。通过这种方法，可以轻松评估反应的产率、选择性和动力学。该方法还可以扩展到研究相同金属纳米晶体具有不同形态、表面晶面、结构或表面功能化的催化性能。这种方法将广泛适用于评估新催化剂或新化学反应的催化效率和选择性以及这些反应中的动态过程。
