(275c) Combustion-Driven One Step Synthesis of Palladium Alloy Nanostructured Films in a High Temperature Reducing Jet Reactor
In recent years, hydrogen storage and purification became an important area of research. There is an urgent need for a low cost, highly mechanical stable composite metallic membrane that selectively transports hydrogen. Palladium and palladium based alloys have become a promising membrane material in this area due to high selectivity and mobility of hydrogen in the Pd lattice. However, pure palladium is expensive, has low mechanical stability, and is prone to hydrogen embrittlement below 573 K. All these issues can be handled by alloying palladium with comparatively less expensive metals such as copper and silver. Alloying palladium with copper and silver prevents hydrogen embrittlement and results in higher hydrogen permeation fluxes and enhances mechanical stability. We present here the high temperature flame-based synthesis of non-oxide nanostructured palladium alloy films utilizing a high temperature reducing jet (HTRJ) reactor. We synthesized bimetallic palladium-copper, palladium-silver and ternary palladium-copper-silver hybrid films. The HTRJ process allows us to decouple the flame chemistry from the nanoparticle formation chemistry. We synthesized these hybrid films in one step by thermal decomposition of low-cost, water soluble, and environmentally friendly precursors. The as-prepared films were sintered at 200oC inside the HTRJ reactor, eliminating the need of any post treatment methods to anneal and sinter the films. The metal nanoparticles in nm range were deposited on a 25 micron average pore size SS-316 discs leading to formation of these Pd based films. Hydrogen permeation experiments at different pressure and temperatures using a disc membrane module are in progress. The hybrid films were characterized by powder X-Ray diffraction, SEM and EDX for surface topology and elemental composition. In this presentation, we will describe the HTRJ process briefly, and then focus on the synthesis and characterization of bimetallic Pd-Cu, Pd-Ag, and ternary Pd-Cu-Ag films along with hydrogen permeation results using these membranes.