Zeolite-Encapsulated Pt Nanoparticles for Tandem Catalysis
Zeolite-Encapsulated Pt Nanoparticles for Tandem Catalysis
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DOI：
10.1021/jacs.8b09568
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发表时间：
2018-10-17
影响因子：
15
通讯作者：
Xu, Bingjun
中科院分区：
文献类型：
--
作者：
Cho, Hong Je;Kim, Doyoung;Xu, Bingjun
将金属纳米颗粒包覆在沸石基质中是一种将多个连续反应集成为一锅一步串联催化反应的有前途的途径。我们报告了一种阳离子聚合物辅助合成策略，将Pt纳米颗粒（NPs）封装到MFI沸石中。通过涉及具有不同分子尺寸的底物的模型反应的动力学研究，证明了在合成的催化剂中超过90%的Pt NPs的封装程度。HZSM-5沸石包覆的Pt纳米颗粒能够选择性地介导糠醛和丙酮的串联羟醛缩合和氢化以形成氢化的C-8产物，总收率为87%。相比之下，糠醛的氢化和脱羰在负载于HZSM-5上的Pt NP上在其他相同条件下占主导地位。对串联反应的高选择性的封装的催化剂上归因于金属和酸中心的分布，这限制了糠醛的访问到Pt位，并促进酸催化的羟醛缩合。这是第一次证明串联反应中的产物分布是通过封装来定制催化材料的结构来操纵的。
Encapsulation of metal nanoparticles in a zeolite matrix is a promising route to integrate multiple sequential reactions into a one-pot and one-step tandem catalytic reaction. We report a cationic polymer-assisted synthetic strategy to encapsulate Pt nanoparticles (NPs) into MFI zeolites. Degrees of encapsulation of Pt NPs in the synthesized catalysts exceeding 90% were demonstrated via kinetic studies of model reactions involving substrates with different molecular dimensions. HZSM-5 zeolite-encapsulated Pt NPs are able to selectively mediate the tandem aldol condensation and hydrogenation of furfural and acetone to form hydrogenated C-8 products with a combined yield of 87%. In contrast, hydrogenation and decarbonylation of furfural dominate on Pt NPs supported on HZSM-5 at otherwise identical conditions. The high selectivity toward the tandem reaction on the encapsulated catalyst is attributed to the distribution of metal and acid sites, which limits the access of furfural to Pt sites and promotes the acid-catalyzed aldol condensation. This is the first demonstration that the product distribution in a tandem reaction is manipulated by tailoring the architecture of catalytic materials via encapsulation.