Organic Structure-Directing Agent-Free Synthesis of Mordenite-Type Zeolites Driven by Al-Rich Amorphous Aluminosilicates

Ting Xiao; Mizuho Yabushita; Toshiki Nishitoba; Ryota Osuga; Motohiro Yoshida; Masaki Matsubara; Sachiko Maki; Kiyoshi Kanie; Toshiyuki Yokoi; Wenbin Cao; Atsushi Muramatsu

doi:10.1021/acsomega.0c05059

Organic Structure-Directing Agent-Free Synthesis of Mordenite-Type Zeolites Driven by Al-Rich Amorphous Aluminosilicates

ACS Omega. 2021 Feb 16;6(8):5176-5182. doi: 10.1021/acsomega.0c05059. eCollection 2021 Mar 2.

Authors

Ting Xiao^{1

2}, Mizuho Yabushita³, Toshiki Nishitoba⁴, Ryota Osuga¹, Motohiro Yoshida¹, Masaki Matsubara^{1

5}, Sachiko Maki⁶, Kiyoshi Kanie^{1

6}, Toshiyuki Yokoi⁴, Wenbin Cao², Atsushi Muramatsu^{1

6

7}

Affiliations

¹ Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
² Department of Inorganic Nonmetallic Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
³ Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
⁴ Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
⁵ National Institute of Technology, Sendai College, 48 Nodayama, Medeshima-Shiote, Natori, Miyagi 981-1239, Japan.
⁶ International Center for Synchrotron Radiation Innovation Smart, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
⁷ Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.

Abstract

Mordenite (MOR)-type zeolites with a Si/Al molar ratio of up to 13 with crystallite sizes of ca. 60 nm were successfully synthesized from Al-rich aluminosilicates with a Si/Al ratio of 2 and additional SiO₂ under seed-assisted hydrothermal conditions for 6 h or longer without any organic structure-directing agents (OSDAs). In stark contrast, under the same hydrothermal conditions for 6 h, control experiments using starting reagent(s), such as Al-poor aluminosilicate, pure SiO₂, tetraethyl orthosilicate, and Al(NO₃)₃, all of which are typically employed for zeolite synthesis, failed to yield MOR-type zeolites. The penta-coordinated Al species, which are present in Al-rich aluminosilicates and are more reactive than the tetra- and hexa-coordinated Al species typically found in alumina and Al-poor aluminosilicates, played a decisive role in the OSDA-free synthesis of MOR-type zeolites.