Yao Jie, He Yingluo, Zeng Yan, Feng Xiaobo, Fan Jiaqi, Komiyama Shoya, Yong Xiaojing, Zhang Wei, Zhao Tiejian, Guo Zhongshan, Peng Xiaobo, Yang Guohui, Tsubaki Noritatsu
Department of Applied Chemistry, School of Engineering, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan.
Jiangsu Province Engineering Research Center of Fine Utilization of Carbon Resources, China University of Mining & Technology, Xuzhou, 221116, Jiangsu, China.
Nat Commun. 2022 Feb 17;13(1):935. doi: 10.1038/s41467-022-28606-z.
Reduction process is a key step to fabricate metal-zeolite catalysts in catalytic synthesis. However, because of the strong interaction force, metal oxides in zeolites are very difficult to be reduced. Existing reduction technologies are always energy-intensive, and inevitably cause the agglomeration of metallic particles in metal-zeolite catalysts or destroy zeolite structure in severe cases. Herein, we disclose that zeolites after ion exchange of ammonium have an interesting and unexpected self-reducing feature. It can accurately control the reduction of metal-zeolite catalysts, via in situ ammonia production from 'ammonia pools', meanwhile, restrains the growth of the size of metals. Such new and reliable ammonia pool effect is not influenced by topological structures of zeolites, and works well on reducible metals. The ammonia pool effect is ultimately attributed to an atmosphere-confined self-regulation mechanism. This methodology will significantly promote the fabrication for metal-zeolite catalysts, and further facilitate design and development of low-cost and high-activity catalysts.
还原过程是催化合成中制备金属-沸石催化剂的关键步骤。然而，由于相互作用力较强，沸石中的金属氧化物很难被还原。现有的还原技术总是能源密集型的，并且在严重情况下不可避免地会导致金属-沸石催化剂中金属颗粒的团聚或破坏沸石结构。在此，我们揭示了铵离子交换后的沸石具有有趣且意想不到的自还原特性。它可以通过“氨池”原位产生氨来精确控制金属-沸石催化剂的还原，同时抑制金属尺寸的增长。这种新的、可靠的氨池效应不受沸石拓扑结构的影响，并且对可还原金属效果良好。氨池效应最终归因于一种气氛受限的自调节机制。这种方法将显著促进金属-沸石催化剂的制备，并进一步推动低成本、高活性催化剂的设计与开发。
