A review on “Oxide–Zeolite-Based Composite Catalyst Concept That Enables Syngas Chemistry beyond Fischer–Tropsch Synthesis (https://pubs.acs.org/doi/10.1021/acs.chemrev.0c01012)” was just published by Chemical Reviews, co-authored by Prof. Xiulian Pan, Dr. Feng Jiao, Dr. Dengyun Miao and Prof. Xinhe Bao from Dalian Institute of Chemical Physics. The paper reviews the state of the art, opportunities and challenges of the OXZEO catalysis concept in the field of C1 chemistry.
The key of C1 chemistry lies in controlled C-C coupling toward desired products without forming byproducts, which remains a challenge. The team of Prof. Xiulian Pan and Prof. Xinhe Bao reported a novel catalyst concept based on metal oxide-zeolite bifunctional catalysts (OXZEO®) in 2016, which separates activation of reactants CO and H2, and C-C coupling onto two different types of active sites. This turns syngas conversion into a tandem reaction and allows the product selectivity to be manipulated by shape-selective zeolites. Thus it enables direct conversion of syngas to a variety of chemicals and fuels with their selectivities surpassing the limit predicted by Anderson-Schultz-Flory distribution, such as light olefins (C2=-C4=) (Science 2016), ethylene (Angew. Chem. Int. Ed. 2018), high quality gasoline (Angew. Chem. Int. Ed. 2019), ethane or propane (Angew. Chem. Int. Ed. 2020), aromatics and even BTX (ACS Catal. 2020, Chem. Commun. 2017).
This OXZEO® catalyst design concept allows direct conversion of syngas without necessity for water-gas-shift reaction to adjust the H2/CO ratio and extra synthesis stage of intermediates. It provides a new technology for water-saving and highly efficient utilization of coal. The team collaborated with Prof. Zhongmin Liu’s team, and further with Shaanxi Yanchang Petroleum (Group) Co., Ltd, to explore the applications of the syngas-to-light olefins OXZEO®-TO technology. In September 2020, a pilot plant demonstration with a scale of 1000-ton light olefins/annual using coal-derived syngas was successfully completed.
The OXZEO® concept attracts wide attention recently. A rapidly increasing number of studies show that OXZEO® provides a new technology platform for efficient utilization of carbon resources such as coal, natural gas and biomass via syngas in addition to Fischer-Tropsch synthesis and methanol technologies, as well as utilization of CO2 as a carbon resource via hydrogenation to a variety of chemicals and fuels. This paper gives an overview on the development of the bifunctional catalysts for direct syngas conversion, presents the understanding of OXZEO® concept in the selectivity control, and discusses the challenges for further development of highly active and selective catalysts.
This work was supported by Chinese Academy of Sciences, the Ministry of Science and Technology of China, National Natural Science Foundation of China, etc.