Hybrid bio-templated catalysts

Abstract

For decades, ethanol has been in use as a fuel for the storage of solar energy in an energy-dense,liquid form. Over the last decade the ability to reform ethanol into hydrogen gas suitable for fuel cell use has drawn interest as a way to increase the efficiency of both vehicles and standalone power generators. In this work, the M13 virus has been used as a biological scaffold and template to form hybrid Rh-Ni@CeO₂ nanowires. These composite materials have exceptionally high thermal stability, showing a greater than 8 th order growth when made as isolated nanoparticles, and over 2 0 th order growth when assembled into nanowires, compared to the expected 2 nd- 3 rd order behavior. The individual CeO₂ nanoparticles forming the wires are the smallest synthesized to date (1.3 nm), and over 20% of all oxygen sites were shown to be vacant, suggesting a very fast oxygen diffusion rate and highly active redox support enhancement. A chemical reactor was built to test the activity of the hybrid Rh-Ni@CeO₂ nanowires for the catalysis of ethanol into hydrogen gas in comparison to equivalent nanoparticle samples. Both nanowire and nanoparticle catalysts formed using these techniques showed excellent performance at only 300 C, and nanowires showed significantly improved resistance to deactivation over time on-stream. This study suggests that the use of biotemplating in the production of catalysts is a promising route to significant gains over traditional catalyst manufacture methods.