An ultra-thin and super-long Na2V6O16·xH2O nanoribbon of ∼5 nm thickness and ∼500 μm length was synthesized by a hydrothermal method, using a freshly prepared V(3+) species precursor solution by directly dissolving a vanadium metal thread in a NaNO3 solution using a solid-liquid phase arc discharge (SLPAD) technique. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were used to characterize the structure, morphology, and chemical composition. The super-long and ultra-thin geometry of the Na2V6O16·xH2O nanoribbons is proven to greatly promote the photocatalytic activity toward reduction of CO2 into renewable hydrocarbon fuel (CH4) in the presence of water vapor under visible-light irradiation.