Effect of promoter in hierarchical hollow Pt/Beta catalysts on the hydrodeoxygenation of phenol

A surface modification strategy to prepare hierarchical Beta molecular sieves for glucose dehydration

“…In our previous research, penta- and hexa-coordinated aluminum species disappear when Beta-P is transformed to Beta-A. 23 As shown in Fig. 9, tetra-, penta-, and hexa-coordinated aluminum species are observed and confirmed by NMR signals at 56, 28, and 0 ppm, respectively.…”

“…In our previous research, mesopores are well dispersed on the internal and external surfaces of Beta molecular sieves in Beta-A. 23 When organic bases are introduced, mesopores are adjacent to the external surface as the molecular size of organic base increases, and the external surface of Beta molecular sieves is well protected from being etched by NaOH solution (Fig. 3D).…”

“…24 In our previous research, signals at 3774, 3653, and 3590 cm −1 disappear after NaOH etching due to the removal of aluminum hydroxyl groups. 23 It demonstrates that aluminum atoms in Beta-P are removed along with the desilication process in Beta-A. Aluminum hydroxyl groups are protected from being etched with organic bases in Beta-PyC, Beta-DPyC, and Beta-TPyC.…”

HPW supported on ammonium hexafluorosilicate modified Hβ: Efficient catalysts for ethylene glycol and methyl tert‐butyl ether reaction with high selectivity and stability

“…22,23 So far, researches on the reduction of zeolite acid strength by post-treatment mainly focused on the following: (1) alkali solution (e.g., tetrapropylammonium hydroxide [TPAOH], NaOH, and a mixture of TPAOH and NaOH solution) treatment of zeolites. [24][25][26] Part of Si and Al species from the zeolites framework are usually removed by alkali solution, increasing the density of strong acid sites in the zeolite. 26 (2) Acid (e.g., HCl, 27 citric acid, 28 HNO 3 , 29 and oxalic acid and tartaric acid 30 ) treatment of zeolites.…”

“…[24][25][26] Part of Si and Al species from the zeolites framework are usually removed by alkali solution, increasing the density of strong acid sites in the zeolite. 26 (2) Acid (e.g., HCl, 27 citric acid, 28 HNO 3 , 29 and oxalic acid and tartaric acid 30 ) treatment of zeolites. The acid treatment effectively removes aluminum from zeolites, obtaining high silica zeolites, 29 while the acid strength of the zeolites is reduced.…”