Template-assisted preparation of metal-modified SAPO-34 molecular sieves for the catalysis of methanol-to-olefins

SAPO-34 Catalyst: Synthesis Optimization by Template Alteration and In Situ Coke Evolution Analysis in Methanol Conversion to Light Olefins

“…Further analysis of the nature of the acidic sites was conducted using DRIFT-FTIR over the TEAOH-1 sample saturated with deuterated acetonitrile (CD 3 CN) as the probe molecule. As depicted in Figure (a), characteristic peaks related to the SAPO-34 framework have emerged in the range of 700–1700 cm –1 . − The CD 3 CN-saturated sample pointed out peaks at 2117, 2269, and 2314 cm –1 that are attributed to the symmetric vibration of CD 3 , and CN interactions with BAS and LAS, respectively. , The blank sample, as expected, had no peaks in the interval 2100–2400 cm –1 . The broad peak in the band region of 3100–3700 cm –1 was due to adsorbed water that diminished at elevated temperatures.…”

Uncovering the role of Lewis and Brønsted acid sites in perforated SAPO-34 with an enhanced lifetime in methanol conversion to light olefins

“…5, all the samples show characteristic peaks related to the SAPO-34 framework in the range of 700–1700 cm −1 . 40–43 The CD 3 CN-saturated samples point out peaks at 2117, 2270 and 2314 cm −1 that are attributed to the symmetric vibration of CD 3 , CN interaction with BAS and CN interaction with LAS, respectively, while the blank 4.0 DEA/SAPO-34 sample ( i.e. , not saturated with CD 3 CN, grey curve in Fig.…”

Nanosheets of Ni‐SAPO‐34 Molecular Sieve for Selective Oxidation of Cyclohexanone to Adipic Acid

“…The redox reactivity of the nickel species in NS−Ni‐SAPO‐34 is preliminarily detected by H 2 ‐TPR measurements (Figure 3e) and compared with NiO/SiO 2 and NiO/NS−Ni‐SAPO‐34. The peaks of hydrogen consumption of NS−Ni‐SAPO‐34 cannot be ascribe to the reduction of commonly impregnated nickel species as reported with some molecular sieves as supports, for example, Ni/NiO/Ni(OH) 2 on SAPO‐34/ZSM‐5/MCM‐41, etc., [9] and should be attributed to the reduction of nickel speices strongly interacted with the framework of molecular sieves, i. e., incorporated into the zeolite framework [10] . The framework incorporated nickel should play a vital role to stabilize the ultrathin morphology of the zeolite, for no crystallized molecular sieves were obtianed in similar preparation but without addition of nickel speices.…”

“…Neither of above three impregnated Ni 2 + peaks can be detected in NSÀ Ni-SAPO-34, while the peaks of NSÀ Ni-SAPO-34 cannot ascribe to common impregnated nickel species on different kinds of molecular sieves reported by previous literatures, [9] indicative of the incorporation of nickel into the framework of NSÀ Ni-SAPO-34, not the isolated Ni 2 + cation or NiO cluster. [10] Furthermore, the binding energy of O1s at 532.4 eV (Supporting Information, Figure S9) can be assigned to the framework oxygen of molecular sieve, not the lattice oxygen of nickel oxide.…”

“…The peaks of hydrogen consumption of NSÀ Ni-SAPO-34 cannot be ascribe to the reduction of commonly impregnated nickel species as reported with some molecular sieves as supports, for example, Ni/NiO/Ni(OH) 2 on SAPO-34/ZSM-5/MCM-41, etc., [9] and should be attributed to the reduction of nickel speices strongly interacted with the framework of molecular sieves, i. e., incorporated into the zeolite framework. [10] The framework incorporated nickel should play a vital role to stabilize the ultrathin morphology of the zeolite, for no crystallized molecular sieves were obtianed in similar preparation but without addition of nickel speices. Compared with commonly impreg- Chemistry-A European Journal nated or exchanged nickel species over bulky molecular sieves, the NSÀ Ni-SAPO-34 should show some new characteristics of catalysis.…”