Huang, Pin-PinPin-PinHuangQorbani, MohammadMohammadQorbaniHung, Ying-TiYing-TiHungLai, Ying-RenYing-RenLaiSabbah, AmrAmrSabbahTseng, Mao-FengMao-FengTsengHuang, Chih-YangChih-YangHuangKoodathil, SumangaladeviSumangaladeviKoodathilKholimatussadiah, SeptiaSeptiaKholimatussadiahHussien, Mahmoud KamalMahmoud KamalHussienFeng, Tzu-HsuanTzu-HsuanFengLiu, Yo-HsunYo-HsunLiuWang, HsinHsinWangLin, Jia-WeiJia-WeiLinWang, Chen-HaoChen-HaoWangWu, Chih-IChih-IWuHayashi, MichitoshiMichitoshiHayashiChen, Kuei-HsienKuei-HsienChenChen, Li-ChyongLi-ChyongChen2026-03-112026-03-112026-01-0719360851https://www.scopus.com/record/display.uri?eid=2-s2.0-105027732834&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/736204The 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 SiO2-capped vapor–liquid–solid (VLS) growth method that assists in substituting vanadium into the molybdenum disulfide ultrathin film and introducing sulfur vacancies to form Svac-Mo1–xVxS2. By optimizing the thickness of solid precursors and the SiO2-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–Svac pairs, manifesting in the enhanced Svac 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 CO2 or H2O on the surface, improved charge transfer/transport, and a suitable energy band diagram. Furthermore, the 2D Svac-Mo1–xVxS2 model catalyst films, with abundant V–Svac pair active sites, exhibit a stable and boosted photocatalytic CO2 reduction to CO, specifically yielding ∼5 times more than that of pristine MoS2. Our study demonstrates the origin of V–Svac pairs in host MoS2, leading to basal plane activation. This suggests a foundation for future research on pairing dopants or alloying elements with defects for efficient photocatalyst design.true2D materialsCO2reductionphotocatalysisscanning electrochemical microscopysemicondcutordopant−vacancy pairingVLS growth methodjournal article10.1021/acsnano.5c173672-s2.0-105027732834