Preparation of Ni/TiO₂ composite hollow fibers by electroless plating

Ni/TiO₂ composite hollow fibers with an outer diameter of ca. 560 μm and inner diameter of ca. 500 μm were successfully prepared by electroless plating using TiO₂ hollow fibers as supports. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX), and tensile strength test. The results revealed that the Ni/TiO₂ composite hollow fibers were made up of nickel outer layer and TiO₂ inner layer and exhibited excellent tensile strength ascribed from the nickel layer. The thickness of the nickel layer could be readily controlled by varying the electroless time and the tensile strength of the composite hollow fibers increased with prolonging the electroless time. The tensile strength was up to 52.1 MPa when the nickel layer was ca. 22 μm. The composite hollow fibers showed stable selectivities of H₂ over N₂ from 6 to 10 and H₂ permeation in the order of 10^-9 mol m^-2 s^-1 Pa^-1 at 453 K.