Lin Jia, Zhao Lusi, Zheng Yong, Xiao Yihong, Yu Guangtao, Zheng Ying, Chen Wei, Jiang Lilong
College of Chemistry and Materials Science, Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical Engineering, Fujian Normal University, Fuzhou, Fujian 350007, P. R. China.
College of Environmental Science and Engineering, Fujian Normal University, Fuzhou, Fujian 350007, P. R. China.
ACS Appl Mater Interfaces. 2020 Dec 16;12(50):56095-56107. doi: 10.1021/acsami.0c18188. Epub 2020 Dec 2.
It is of practical importance to develop a stable and accessible methane combustion catalyst which could retain an excellent activity under drastic conditions. Herein, we introduce a facile approach to extend the stability of conventional Pd/AlO catalysts through tailoring the pore size of mesoporous aluminas (MAs) and the interaction between Pd and Al. By modulating the addition of templates (deoxycholic acid and polyvinylpyrrolidone), a series of MAs with tunable and uniform pore size were obtained through a designed sol-gel method. Unexpectedly, Pd/MA-800-5 catalyst prepared with relatively large pore size (ca. 12 nm) MAs exhibited an efficient and sustained performance under a variety of operating conditions, while those prepared with small pore size (ca. 5-7 nm) MAs suffered from a significant loss of activity during high temperature cyclic reactions (280-850 °C) due to the decomposition of confined PdO. The enhancement could be attributed to the suitable particle size, higher crystallinity, generated active sites, improved reducibility, and thermal stability of PdO species. Moreover, the variation of pore size also resulted in a different reaction mechanism. Such a pore size promotion strategy effectively invoked a superior catalytic performance while keeping the catalyst components simple, which can be extended to prepare other high-performance metal oxide-supported catalysts for catalytic applications.
开发一种稳定且易于获得的甲烷燃烧催化剂具有实际重要性，该催化剂在苛刻条件下仍能保持优异的活性。在此，我们介绍一种简便方法，通过调整介孔氧化铝（MA）的孔径以及钯与铝之间的相互作用来提高传统钯/氧化铝催化剂的稳定性。通过调节模板（脱氧胆酸和聚乙烯吡咯烷酮）的添加量，采用设计的溶胶-凝胶法获得了一系列孔径可调且均匀的MA。出乎意料的是，用相对较大孔径（约12纳米）的MA制备的钯/MA-800-5催化剂在各种操作条件下表现出高效且持续的性能，而用小孔径（约5-7纳米）的MA制备的催化剂在高温循环反应（280-850℃）期间由于受限的PdO分解而活性显著损失。这种增强可归因于合适的粒径、更高的结晶度、产生的活性位点、改善的还原性以及PdO物种的热稳定性。此外，孔径的变化还导致了不同的反应机理。这种孔径促进策略在保持催化剂成分简单的同时有效地引发了优异的催化性能，可扩展用于制备其他用于催化应用的高性能金属氧化物负载催化剂。
