Counting the Acid Sites in a Commercial ZSM-5 Zeolite Catalyst.

Autor:	Zachariou A; School of Chemistry, University of Glasgow, Joseph Black Building, GlasgowG12 8QQ, U.K.; UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, ChiltonOX11 0FA, Oxon, U.K., Hawkins AP; School of Chemistry, University of Glasgow, Joseph Black Building, GlasgowG12 8QQ, U.K.; UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, ChiltonOX11 0FA, Oxon, U.K., Howe RF; Department of Chemistry, University of Aberdeen, AberdeenAB24 3UE, U.K., Skakle JMS; Department of Chemistry, University of Aberdeen, AberdeenAB24 3UE, U.K.; Department of Physics, University of Aberdeen, AberdeenAB24 3UE, U.K., Barrow N; Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading, BerkshireRG4 9NH, U.K., Collier P; Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading, BerkshireRG4 9NH, U.K., Nye DW; ISIS Facility, STFC Rutherford Appleton Laboratory, ChiltonOX11 0QX, Oxon, U.K., Smith RI; ISIS Facility, STFC Rutherford Appleton Laboratory, ChiltonOX11 0QX, Oxon, U.K., Stenning GBG; ISIS Facility, STFC Rutherford Appleton Laboratory, ChiltonOX11 0QX, Oxon, U.K., Parker SF; School of Chemistry, University of Glasgow, Joseph Black Building, GlasgowG12 8QQ, U.K.; UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, ChiltonOX11 0FA, Oxon, U.K.; ISIS Facility, STFC Rutherford Appleton Laboratory, ChiltonOX11 0QX, Oxon, U.K., Lennon D; School of Chemistry, University of Glasgow, Joseph Black Building, GlasgowG12 8QQ, U.K.
Jazyk:	angličtina
Zdroj:	ACS physical chemistry Au [ACS Phys Chem Au] 2022 Nov 01; Vol. 3 (1), pp. 74-83. Date of Electronic Publication: 2022 Nov 01 (Print Publication: 2023).
DOI:	10.1021/acsphyschemau.2c00040
Abstrakt:	This work investigates the acid sites in a commercial ZSM-5 zeolite catalyst by a combination of spectroscopic and physical methods. The Brønsted acid sites in such catalysts are associated with the aluminum substituted into the zeolite lattice, which may not be identical to the total aluminum content of the zeolite. Inelastic neutron scattering spectroscopy (INS) directly quantifies the concentrations of Brønsted acid protons, silanol groups, and hydroxyl groups associated with extra-framework aluminum species. The INS measurements show that ∼50% of the total aluminum content of this particular zeolite is extra framework, a conclusion supported by solid-state NMR and ammonia temperature-programmed desorption (TPD) measurements. Evidence for the presence of extra-framework aluminum oxide species is also seen in neutron powder diffraction data from proton- and deuterium-exchanged samples. The differences between results from the different analytical methods are discussed, and the novelty of direct proton counting by INS in this typical commercial catalyst is emphasized. Competing Interests: The authors declare no competing financial interest. (© 2022 The Authors. Published by American Chemical Society.)
Databáze:	MEDLINE
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