TY - GEN
T1 - The crystal quality and structure of AM6
AU - Tekin, Rumeysa
AU - Warzywoda, Juliusz
AU - Sacco, Albert
N1 - Publisher Copyright:
Copyright © (2017) by AIChE. All rights reserved.
PY - 2017
Y1 - 2017
N2 - Microporous vanadosilicate AM-6, isostructural with titanosilicate ETS-10, is a novel promising material in the traditional zeolite applications such as catalysis, photocatalysis, gas separation, sorption and the monatomic –O-V-O-V-O chains have shown potential for use in quantum wire application. High purity vanadosilicate AM-6 products with different crystal quality (disorder, or average length of the V-O-V chains in the AM-6 framework) and sizes in the range of ~50 nm to ~6 μm were hydrothermally synthesized at 448-503 K using tetramethylammonium (TMA+) ions. The combined SEM, EDX, XRD, Raman, TGA, XPS, and nitrogen adsorption isotherm data showed that by treating these as-synthesized materials in gaseous ammonia at 673 K it is possible to completely remove TMA+ ions from the AM-6 pores without adversely affecting product crystallinity and the micropore structure of AM-6, and with only minimal degradation of crystal quality of the resulting products. However, the success in a complete removal of TMA+ ions without affecting other crystalochemical characteristics of the product depended on its initial crystal quality. TMA+ ions could not be completely removed from the lowest crystal quality product (FWHM=20.3 cm-1) without completely decomposing the V-O-V chains. The intermediate crystal quality product (FWHM=15.0 cm-1) could be successfully ammonia-treated only at 673 K to remove TMA+ ions, but higher temperatures resulted in a complete decomposition of the V-O-V chains. The highest crystal quality product (FWHM=12.7 cm-1) retained the integrity of V-O-V chains as well as the long range order and the micropore structure when ammonia-treated up to 748 K.
AB - Microporous vanadosilicate AM-6, isostructural with titanosilicate ETS-10, is a novel promising material in the traditional zeolite applications such as catalysis, photocatalysis, gas separation, sorption and the monatomic –O-V-O-V-O chains have shown potential for use in quantum wire application. High purity vanadosilicate AM-6 products with different crystal quality (disorder, or average length of the V-O-V chains in the AM-6 framework) and sizes in the range of ~50 nm to ~6 μm were hydrothermally synthesized at 448-503 K using tetramethylammonium (TMA+) ions. The combined SEM, EDX, XRD, Raman, TGA, XPS, and nitrogen adsorption isotherm data showed that by treating these as-synthesized materials in gaseous ammonia at 673 K it is possible to completely remove TMA+ ions from the AM-6 pores without adversely affecting product crystallinity and the micropore structure of AM-6, and with only minimal degradation of crystal quality of the resulting products. However, the success in a complete removal of TMA+ ions without affecting other crystalochemical characteristics of the product depended on its initial crystal quality. TMA+ ions could not be completely removed from the lowest crystal quality product (FWHM=20.3 cm-1) without completely decomposing the V-O-V chains. The intermediate crystal quality product (FWHM=15.0 cm-1) could be successfully ammonia-treated only at 673 K to remove TMA+ ions, but higher temperatures resulted in a complete decomposition of the V-O-V chains. The highest crystal quality product (FWHM=12.7 cm-1) retained the integrity of V-O-V chains as well as the long range order and the micropore structure when ammonia-treated up to 748 K.
KW - AM-6
KW - Crystal quality
KW - Gaseous ammonia treatment
KW - Hydrothermal synthesis
KW - Nanocrystals
KW - Vanadosilicates
UR - http://www.scopus.com/inward/record.url?scp=85048453834&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85048453834
T3 - Materials Engineering and Sciences Division 2017 - Core Programming Area at the 2017 AIChE Annual Meeting
SP - 107
EP - 148
BT - Materials Engineering and Sciences Division 2017 - Core Programming Area at the 2017 AIChE Annual Meeting
PB - AIChE
T2 - Materials Engineering and Sciences Division 2017 - Core Programming Area at the 2017 AIChE Annual Meeting
Y2 - 29 October 2017 through 3 November 2017
ER -