Two-step engineering of porous MoS2 nanofibers for enhanced charge separation, photocatalytic rhodamine B degradation and photoelectrochemical performance.

Engineering MoS2 architectures that simultaneously provide efficient light harvesting, charge separation, interfacial transport, and accessible reactive sites remains challenging for photocatalytic and photoelectrochemical applications. Herein, porous mixed-phase 1T/2H MoS2 nanofibers were fabricated through a two-step strategy combining hydrothermal synthesis with electrospinning-assisted fiber construction. The resulting interconnected architecture integrates semiconducting 2H-MoS2 with conductive 1T-rich domains and an accessible porous interface, providing favorable pathways for photogenerated carrier transport and surface reactions. The MoS2 nanofibers exhibited broad visible-light absorption with an optical band gap of approximately 1.56 eV and achieved 89.60% rhodamine B (RhB) degradation within 120 min under simulated sunlight, with an apparent pseudo-first-order rate constant of 1.27 × 10-2 min-1. Approximately 96.5% of the initial photocatalytic activity was retained after three consecutive cycles. Reactive-species trapping identified photogenerated holes (h+) and superoxide radicals (˙O2 -) as the dominant oxidative species, consistent with the estimated band energetics. When directly integrated onto FTO, the porous nanofiber electrode displayed reproducible photoresponse with approximately 94% retention after eight light-dark cycles. Illumination decreased the charge-transfer resistance from 52.3 kΩ to 44.6 kΩ and the interfacial relaxation time from 1.38 to 1.14 s, indicating accelerated interfacial carrier transfer. Mott-Schottky analysis further confirmed predominantly n-type behavior. These results establish a direct relationship among mixed-phase electronic structure, porous fibrous architecture, and photogenerated charge utilization, demonstrating a viable phase-and-morphology engineering strategy for developing MoS2-based materials for solar-driven photocatalytic and photoelectrochemical applications.