Cerium Photocatalyst in Action: Structural Dynamics in the Presence of Substrate Visualized via Time-Resolved X-ray Liquidography

Yunbeom Lee; Hosung Ki; Donghwan Im; Seunghwan Eom; Jain Gu; Seonggon Lee; Jungmin Kim; Yongjun Cha; Kyung Won Lee; Serhane Zerdane; Matteo Levantino; Hyotcherl Ihee

doi:10.1021/jacs.3c08166

Cerium Photocatalyst in Action: Structural Dynamics in the Presence of Substrate Visualized via Time-Resolved X-ray Liquidography

J Am Chem Soc. 2023 Nov 1;145(43):23715-23726. doi: 10.1021/jacs.3c08166. Epub 2023 Oct 19.

Authors

Yunbeom Lee^{1

2}, Hosung Ki^{1

2}, Donghwan Im^{1

2}, Seunghwan Eom^{1

2}, Jain Gu^{1

2}, Seonggon Lee^{1

2}, Jungmin Kim^{1

2}, Yongjun Cha^{1

2}, Kyung Won Lee^{1

2}, Serhane Zerdane³, Matteo Levantino³, Hyotcherl Ihee^{1

2}

Affiliations

¹ Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea.
² Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
³ European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France.

Abstract

[Ce(III)Cl₆]^3-, with its earth-abundant metal element, is a promising photocatalyst facilitating carbon-halogen bond activation. Still, the structure of the reaction intermediate has yet to be explored. Here, we applied time-resolved X-ray liquidography (TRXL), which allows for direct observation of the structural details of reaction intermediates, to investigate the photocatalytic reaction of [Ce(III)Cl₆]^3-. Structural analysis of the TRXL data revealed that the excited state of [Ce(III)Cl₆]^3- has Ce-Cl bonds that are shorter than those of the ground state and that the Ce-Cl bond further contracts upon oxidation. In addition, this study represents the first application of TRXL to both photocatalyst-only and photocatalyst-and-substrate samples, providing insights into the substrate's influence on the photocatalyst's reaction dynamics. This study demonstrates the capability of TRXL in elucidating the reaction dynamics of photocatalysts under various conditions and highlights the importance of experimental determination of the structures of reaction intermediates to advance our understanding of photocatalytic mechanisms.