A novel hybrid artificial photosynthesis system using MoS₂ embedded in carbon nanofibers as electron relay and hydrogen evolution catalyst

Inspired by photosynthesis in nature, artificial photosynthesis (AP) systems have been widely investigated in the context of energy and environmental research. Here we report a noble-metal-free AP system for visible-light-driven H₂ generation from aqueous solutions consisting of fluorescein (FL) as photosensitizer, single-layer ultrasmall MoS₂ nanoplates embedded in carbon nanofibers (CNF) as electron relay and redox catalyst, and triethanolamine (TEOA) as sacrificial electron donor. This CNF–MoS₂/FL system exhibits outstanding H₂ evolution performance, with an H₂ generation rate that exceeds not only both MoS₂/FL (by 100%) and CNF/FL (by 1100%), but also the Pt/FL system (by 40%). The excellent photocatalytic activity of this CNF–MoS₂/FL system can be ascribed to the synergistic effects of CNF and MoS₂ coupling: (1) the simultaneous presence of MoS₂ with its delocalized and increased Mo 4d unoccupied states and of CNF with increased graphitic characteristics enables electron transfer from FL^∗ to MoS₂ via CNF electron relay; (2) the single-layered ultrasmall MoS₂ nanoplates with short effective lengths for electron transfer and high density of reactive S-edges effectively catalyze the H₂ evolution reaction (HER). The presented work successfully fabricated a highly efficient AP system for solar H₂ production from a fully aqueous solution and indicated CNF–MoS₂ as a promising candidate to replace Pt for solar fuel conversion.