Author : Robert William Atkinson (III)
Publisher :
ISBN 13 :
Total Pages : 223 pages
Book Rating : 4.:/5 (13 download)
Book Synopsis Vapor Synthesis and Thermal Evolution of Supportless, Metal Nanotubes and Application as Electrocatalysts by : Robert William Atkinson (III)
Download or read book Vapor Synthesis and Thermal Evolution of Supportless, Metal Nanotubes and Application as Electrocatalysts written by Robert William Atkinson (III) and published by . This book was released on 2015 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the major limitations of proton exchange membrane fuel cells (PEMFCs) is the high cost and poor durability of the currently preferred catalyst design, small Pt nanoparticles supported on high surface area carbon (Pt/C). Unsupported, high-aspect ratio nanostructured catalysts, or extended surface catalysts, are a promising paradigm as electrocatalysts for a number of electrochemical reactions. These extended surface catalysts generally exhibit higher specific activities compared to carbon-supported nanoparticle counterparts that have been ascribed to the unique electronic, surface and structural properties of these materials. Extended surface catalysts frequently maintain enhanced durability over supported catalysts during fuel cell operation because these materials are not susceptible to the same modes of degradation inherent to small supported nanoparticles. Considering the promise of extended surfaces as catalysts, we have synthesized metallic, mixed-phase, and alloyed bimetallic nanotubes by a chemical vapor deposition (CVD) technique to catalyze a number of reactions relevant for fuel cells. In this CVD process, metalorganic precursors, namely metal-acetylacetonates, are decomposed by a mild thermal treatment and deposited as conformal nanoparticulate layers within a sacrificial anodic alumina template. Following vapor deposition, the nanotube samples may be annealed while still in the template to induce a series of changes with implications on electrocatalysis, including porosity, alloying, and increases in surface coordination. The metallic nanotubes prepared by this method are highly active catalysts for a host of electrochemical reactions that are promising for fuel cell applications. The effects of composition, heat treatment temperature and gas environment on the activity and durability of these materials have been studied for oxygen reduction, methanol oxidation, formic acid oxidation, and hydrogen oxidation.