Boosting Methanol‐Mediated CO<sub>2</sub> Hydrogenation into Aromatics by Synergistically Tailoring Oxygen Vacancy and Acid Site Properties of Multifunctional Catalyst
Wenhang Wang, Ruosong He, Yang Wang, Meng Li, Jianxin Liu, Jiaming Liang, Shuhei Yasuda, Qiang Liu, Mingbo Wu, Noritatsu Tsubaki
Abstract
Abstract Even though the direct hydrogenation of CO 2 into aromatics has been realized via a methanol‐mediated pathway and multifunctional catalyst, few works have been focused on the simultaneously rational design of each component in multifunctional catalyst to improve the performance. Also, the structure‐function relationship between aromatics synthesis performance and the different catalytic components (reducible metal oxide and acidic zeolite) has been rarely investigated. Herein, we increase the oxygen vacancy (O v ) density in reducible Cr 2 O 3 by sequential carbonization and oxidation (SCO) treatments of Cr‐based metal–organic frameworks. Thanks to the enriched O v , Cr 2 O 3 ‐based catalyst affords high methanol selectivity of 98.1 % (without CO) at a CO 2 conversion of 16.8 % under high reaction temperature (350 °C). Furthermore, after combining with the acidic zeolite H‐ZSM‐5, the multifunctional catalyst realizes the direct conversion of CO 2 into aromatics with conversion and selectivity as high as 25.4 % and 80.1 % (without CO), respectively. The property of acid site in H‐ZSM‐5, especially the Al species that located at the intersection of straight and sinusoidal channels, plays a vital role in enhancing the aromatics selectivity, which can be precisely controlled by varying the hydrothermal synthesis conditions. Our work provides a synergistic strategy to boost the aromatics synthesis performance from CO 2 hydrogenation.