Effects of Electrospinning Solution Properties on Formation of Beads in Tio2 Fibers with PdO Particles

Abstract

TiO₂ fibers with catalytic PdO particles are of interest for use as porous catalytic converters to react NO_x and CO to control air pollution. The fibers are first electrospun as template polymer fibers. The template polymer fibers are calcined to form the ceramic fibers. The electrospinning solution composition significantly affects the average fiber diameter and fiber morphologies (beads) which in turn affect the catalyst performance. In this work, solutions containing Polyvinylpyrrolidone (PVP), Titanium (IV) Isopropoxide (TTIP), and Palladium (II) Chloride (PdCl₂) were electrospun with the goal of fabricating beadless submicron composite fibers. The fibers were calcined to produce ceramic TiO₂ submicron fibers with Palladium oxide (PdO) nanoparticles. To determine the solution recipes that form smooth PdO-TiO₂ fibers without beads, fibers were electrospun and evaluated from solutions with varied mass concentrations of PVP and PdCl₂ salt. The solution concentrations indirectly influenced the electrospinning performance through solution viscosity, surface tension and electrical conductivity. The ceramic fibers were produced with average diameters in the range of 180–280 nm and with minimal formation of beads when the solution had viscosity in the range of 52 to 80 cP and conductivity in the range of 45–67 μs/cm. It was found that the surface tension of the solutions did not vary significantly and did not strongly affect the formation of beads.