Potassium-Promoted Limestone for Preferential Direct Hydrogenation of Carbonates in Integrated CO2 Capture and Utilization

Shuzhuang Sun; Zheng Chen; Yikai Xu; Yuanyuan Wang; Yingrui Zhang; Catherine Dejoie; Shaojun Xu; Xin Xu; Chunfei Wu

doi:10.1021/jacsau.3c00403

Potassium-Promoted Limestone for Preferential Direct Hydrogenation of Carbonates in Integrated CO₂ Capture and Utilization

JACS Au. 2023 Nov 9;4(1):72-79. doi: 10.1021/jacsau.3c00403. eCollection 2024 Jan 22.

Authors

Shuzhuang Sun^{1

2}, Zheng Chen³, Yikai Xu^{2

4}, Yuanyuan Wang², Yingrui Zhang², Catherine Dejoie⁵, Shaojun Xu^{6

7}, Xin Xu³, Chunfei Wu²

Affiliations

¹ School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China.
² School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT7 1NN, U.K.
³ Department of Chemistry, Fudan University, Shanghai, 200433, China.
⁴ Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
⁵ European Synchrotron Radiation Facility, Grenoble, 38043, France.
⁶ Department of Chemical Engineering, University of Manchester, Manchester M13 9PL, U.K.
⁷ UK Catalysis Hub, Research Complex at Harwell, Didcot, OX11 0FA, U.K.

Abstract

Integrated CO₂ capture and utilization (ICCU) via the reverse water-gas shift (RWGS) reaction offers a particularly promising route for converting diluted CO₂ into CO using renewable H₂. Current ICCU-RWGS processes typically involve a gas-gas catalytic reaction whose efficiency is inherently limited by the Le Chatelier principle and side reactions. Here, we show a highly efficient ICCU process based on gas-solid carbonate hydrogenation using K promoted CaO (K-CaO) as a dual functional sorbent and catalyst. Importantly, this material allows ∼100% CO₂ capture efficiency during carbonation and bypasses the thermodynamic limitations of conventional gas-phase catalytic processes in hydrogenation of ICCU, achieving >95% CO₂-to-CO conversion with ∼100% selectivity. We showed that the excellent functionalities of the K-CaO materials arose from the formation of K₂Ca(CO₃)₂ bicarbonates with septal K₂CO₃ and CaCO₃ layers, which preferentially undergo a direct gas-solid phase carbonates hydrogenation leading to the formation of CO, K₂CO₃ CaO and H₂O. This work highlights the immediate potential of K-CaO as a class of dual-functional material for highly efficient ICCU and provides a new rationale for designing functional materials that could benefit the real-life application of ICCU processes.