Pd/TiO2 Nanofibrous Membranes and Their Application in Hydrogen Sensing

Abstract

Pd nanofibers were successfully fabricated using the electrospun TiO2 nanofibers as templates through a simple electroless plating method. The effect of electroless plating parameters on Pd deposition was investigated, and the optimum conditions were determined in terms of the best morphology and integrity of the deposited palladium. The as-prepared membranes were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and transmission electron microscopy. By controlling the electroless plating time, continuous Pd-layer coated or dense Pd nanoparticle decorated nanofibers have been obtained. The as-prepared Pd/TiO2 nanofibrous membranes show good mechanical and conductive properties, offering an excellent sensing platform. Their application for hydrogen detection is demonstrated, and the developed hydrogen sensor exhibits fast response, excellent recovery behavior, and good sensitivity. Two different hydrogen sensing mechanisms were realized in Pd/TiO2 nanofibrous membranes prepared with different deposition times: the resistance increase caused by the formation of palladium hydride and resistance decrease due to a lattice-expansion-induced “break junction”. This study provides a promising route to the facile synthesis of metal nanofibrous membranes through electroless plating, which may have great potential in various applications.