Potassium-promoted limestone for preferential direct hydrogenation of carbonates in integrated CO 2 capture and utilization

Sun, Shuzhuang, Chen, Zheng, Xu, Yikai, Wang, Yuanyuan, Zhang, Yingrui, Dejoie, Catherine, Xu, Shaojun, Xu, Xin and Wu, Chunfei 2024. Potassium-promoted limestone for preferential direct hydrogenation of carbonates in integrated CO 2 capture and utilization. JACS Au 4 (1) , pp. 72-79. 10.1021/jacsau.3c00403

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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.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Additional Information:	License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Start Date: 2023-11-09
Publisher:	American Chemical Society
ISSN:	2691-3704
Date of Acceptance:	23 October 2023
Last Modified:	24 Jan 2024 10:00
URI:	https://orca.cardiff.ac.uk/id/eprint/165796

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