Capped Vapor–Liquid–Solid Growth of Vanadium-Substituted Molybdenum Disulfide Ultrathin Films for Enhanced Photocatalytic Activity
Pin-Pin Huang, Mohammad Qorbani, Ying-Ti Hung, Ying-Ren Lai, Amr Sabbah, Mao-Feng Tseng, Chih-Yang Huang, Sumangaladevi Koodathil, Septia Kholimatussadiah, Mahmoud Kamal Hussien, Tzu-Hsuan Feng, Yo-Hsun Liu, Hsin Wang, Jia-Wei Lin, Chen-Hao Wang, Chih-I Wu, Michitoshi Hayashi, Kuei-Hsien Chen, Chen Li-Chyong
Abstract
High Resolution Image Download MS PowerPoint Slide The exceptional and tunable physicochemical properties of 2D transition metal dichalcogenides (TMDCs) have made them model catalysts for fundamental studies and applications. Activating the inert basal plane holds the key to utilizing wafer-scale TMDCs in artificial photosynthesis. To address this challenge, we report a SiO 2 -capped vapor–liquid–solid (VLS) growth method that assists in substituting vanadium into the molybdenum disulfide ultrathin film and introducing sulfur vacancies to form S vac -Mo 1– x V x S 2 . By optimizing the thickness of solid precursors and the SiO 2 -capping layer (membrane layer), as well as the growth temperature, we demonstrate control over the film thickness, vanadium concentration, and film uniformity. Our results reveal the presence of the V–S vac pairs, manifesting in the enhanced S vac concentration and charge density transfer among V–S–Mo atoms, with multifaceted benefits, including increasing light absorption, photoluminescence quenching, crystal structure distortion, efficient binding of CO 2 or H 2 O on the surface, improved charge transfer/transport, and a suitable energy band diagram. Furthermore, the 2D S vac -Mo 1– x V x S 2 model catalyst films, with abundant V–S vac pair active sites, exhibit a stable and boosted photocatalytic CO 2 reduction to CO, specifically yielding ∼5 times more than that of pristine MoS 2 . Our study demonstrates the origin of V–S vac pairs in host MoS 2, leading to basal plane activation. This suggests a foundation for future research on pairing dopants or alloying elements with defects for efficient photocatalyst design.