CO2 activation on defective MoS2 surfaces for CO2 photo-reduction applications

Yi-Fan Huang^1*, Hsiang-Ting Lien², He-Yun Du², Ying-Ren Lai², Yu-Chung Chang², Ting-Li Lin², Michitoshi Hayashi², Li-Chyong Chen², Kuei-Hsien Chen¹

¹Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
²Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan

* Presenter:Yi-Fan Huang, email:yifanhuang@gate.sinica.edu.tw

CO2 activation on catalyst surface is the very first and critical step in CO2 photoconversion into valuable chemicals. However, CO2 is a thermodynamically stable and chemically inert molecule. How to select and treat the photocatalyst surface to enhance the chemisorption of CO2 and improve its reactivity remains a scientific challenge. Photocatalyst surfaces with functional modifications, such as creating atomic vacancies on surface by H2 plasma treatment are promising candidates for this purpose.
This report reveals the essential first step of CO2 adsorption/activation on defective MoS2 surfaces by using near ambient pressure X-ray photoelectron spectroscopy (NAPXPS), scanning tunneling microscope (STM) experiments and density functional theory (DFT) calculations. These studies not only suggest the atomic sulfur defects on the MoS2 surface particularly play a critical role in activating CO2 to form chemisorbed CO2, but also provide further mechanistic information for the intermediates species, thus guiding the design of better photocatalyst in the future.

Keywords: CO2 Reduction, photocatalyst, near ambient pressure X-ray photoelectron spectroscopy (NAPXPS), MoS2