Silicalite-1 Layer Secures the Bifunctional Nature of a CO2 Hydrogenation Catalyst

Shiyou Xing; Savannah Turner; Donglong Fu; Sophie van Vreeswijk; Yuanshuai Liu; Jiadong Xiao; Ramon Oord; Joachim Sann; Bert M Weckhuysen

doi:10.1021/jacsau.2c00621

Silicalite-1 Layer Secures the Bifunctional Nature of a CO₂ Hydrogenation Catalyst

JACS Au. 2023 Mar 20;3(4):1029-1038. doi: 10.1021/jacsau.2c00621. eCollection 2023 Apr 24.

Authors

Shiyou Xing^{1

2}, Savannah Turner³, Donglong Fu¹, Sophie van Vreeswijk¹, Yuanshuai Liu¹, Jiadong Xiao¹, Ramon Oord¹, Joachim Sann⁴, Bert M Weckhuysen¹

Affiliations

¹ Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterial Science and Institute for Sustainable and Circular Chemistry, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
² Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, Guangdong Province, China.
³ Materials Chemistry and Catalysis Group, Debye Institute for Nanomaterial Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
⁴ Institute of Physical Chemistry, Center for Materials Research (LaMa), Justus-Liebig-University, Gießen Heinrich-Buff-Ring 17, 35392 Gießen, Germany.

Abstract

Close proximity usually shortens the travel distance of reaction intermediates, thus able to promote the catalytic performance of CO₂ hydrogenation by a bifunctional catalyst, such as the widely reported In₂O₃/H-ZSM-5. However, nanoscale proximity (e.g., powder mixing, PM) more likely causes the fast deactivation of the catalyst, probably due to the migration of metals (e.g., In) that not only neutralizes the acid sites of zeolites but also leads to the reconstruction of the In₂O₃ surface, thus resulting in catalyst deactivation. Additionally, zeolite coking is another potential deactivation factor when dealing with this methanol-mediated CO₂ hydrogenation process. Herein, we reported a facile approach to overcome these three challenges by coating a layer of silicalite-1 (S-1) shell outside a zeolite H-ZSM-5 crystal for the In₂O₃/H-ZSM-5-catalyzed CO₂ hydrogenation. More specifically, the S-1 layer (1) restrains the migration of indium that preserved the acidity of H-ZSM-5 and at the same time (2) prevents the over-reduction of the In₂O₃ phase and (3) improves the catalyst lifetime by suppressing the aromatic cycle in a methanol-to-hydrocarbon conversion step. As such, the activity for the synthesis of C₂ ⁺ hydrocarbons under nanoscale proximity (PM) was successfully obtained. Moreover, an enhanced performance was observed for the S-1-coated catalyst under microscale proximity (e.g., granule mixing, GM) in comparison to the S-1-coating-free counterpart. This work highlights an effective shielding strategy to secure the bifunctional nature of a CO₂ hydrogenation catalyst.