Charge Transport Dynamics in Microwave Synthesized One-Dimensional Molybdenum Chalcogenides

Scalable synthesis of one-dimensional molybdenum chalcogenides with tunable electronic properties may be critical for the development of nano-scale electronic device components as well as functional energy-conversion catalysts. Herein we report the direct synthesis of one-dimensional potassium-intercalated molybdenum chalcogenides in the Pseduo-Chevrel-Phase family [K₂Mo₆X₆; X = S, Se, Te] through a rapid microwave-assisted solid-state heating protocol. Interfacial capacitance as well as charge transfer dynamics during aqueous proton reduction are both explored as a function of chalcogen composition. We observe a significant change in the anisotropic nucleation of these structures as the chalcogen increases in size and decreases in electronegativity from sulfur to tellurium, with the former dramatically encouraging nucleation of well-defined nanomaterials in comparison to the latter. These anisotropic structures exhibit increased specific capacitance from 2.25 F g⁻¹ to 10.28 F g⁻¹as the electronegativity of the chalcogen increases (Te<Se<S). Charge transfer kinetics for proton reduction follow a similar chalcogen-dependence, with the smallest charge transfer resistance being 1.16 Ω for K₂Mo₆S₆at -0.6V vs RHE compared to 3.7 Ω for K₂Mo₆Te₆at the same potential. Results discussed herein highlight interesting composition-dependent properties that could guide the future selection and development of molybdenum chalcogenide materials.