American Chemical Society
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Multiple Cuprous Centers Supported on a Titanium-Based Metal–Organic Framework Catalyze CO2 Hydrogenation to Ethylene

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journal contribution
posted on 2021-09-07, 14:37 authored by Lingzhen Zeng, Yonghua Cao, Zhe Li, Yiheng Dai, Yongke Wang, Bing An, Jingzheng Zhang, Han Li, Yang Zhou, Wenbin Lin, Cheng Wang
Hydrogenation of carbon dioxide (CO2) to ethylene (C2H4) can be achieved in two routes via tandem reactions: (1) CO2 hydrogenation to methanol (CH3OH) followed by methanol-to-olefin conversion and (2) reverse water-gas shift reaction followed by Fischer–Tropsch synthesis. Here we present another tandem route for CO2-to-C2H4 conversion via (3) CO2 hydrogenation to ethanol (C2H5OH) followed by C2H5OH dehydration. Multiple cuprous (CuI) centers were loaded onto the Ti82-O)82-OH)4 secondary building units of a Ti-based metal–organic framework (MOF), MIL-125-NH2, via deprotonation and ion exchange of the μ2-OH groups. These multiple CuI centers catalyzed CO2 hydrogenation to C2H5OH, while the Ti22-OM+ (M+ = H+, Li+) sites converted C2H5OH to C2H4. The MOF achieved CO2-to-C2H4 generation rates of up to 2598 μmol gCat–1 h–1 in supercritical CO2 (CO2 30 MPa, H2 5 MPa) at 85 °C and 514 μmol gCat–1 h–1 in the gas phase at 5 MPa (H2:CO2 = 3) and 100 °C, respectively. This work opens another path to selectively producing C2H4 via the hydrogenation of CO2.