Skeletal Alumina Supports Produced Via Atomic Layer Deposition and Applications In Renewable Fuels

Tuesday, October 18, 2011
Exhibit Hall B (Minneapolis Convention Center)
Paul Lichty, Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, Xinhua Liang, Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO, Carl Bingham, National Renewable Energy Laboratory, Golden, CO and Alan W. Weimer, Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO

Fuels production through metal oxide redox cycling can be completely renewable if reduction temperatures are achieved using concentrated solar energy. Many combinations of metal oxides have been investigated over the years and cobalt ferrites show much promise as they have good thermodynamic properties and high melting points. However, bulk ferrites degrade when cycled due to sintering of starting materials and resulting diffusion limitations. Recent work has found that coating the ferrites on rigid supports helps to reduce sintering. When using alumina as a support several Co/Fe/Al spinel species are formed which are capable of being cycled at lower temperatures. Cobalt ferrite has been coated on alumina nano powder and high surface area alumina shells. Large, high surface area polymer particles (~600µm, 43.5 m2/g) were coated via atomic layer deposition (ALD) with several layers of alumina. The alumina layers were applied using TMA/water ALD chemistry. The particles were then heated to 800°C in air to burn out the polymer substrate. The alumina substrates were then coated with alternating layers of Fe2O3 and Co­O using ferrocene and cobaltocene ALD chemistries. ICP results also show metal oxide mass loadings up to 27%. Thermo-chemical cycling was performed in a Netzch DIL 402 thermogravimetric analyzer with CO production measured using an in-situ Netzch QMS 403C mass spectrometer. Particles with alumina supports maintain cycling efficiency as compared to unsupported particles. Testing has been conducted on sun in a multi-tube reflective cavity reactor at the National Renewable Energy Laboratory in Golden, Colorado. Cycling results help to estimate reactor efficiencies.

Extended Abstract: File Not Uploaded
See more of this Session: Particle Technology Forum Poster Session
See more of this Group/Topical: Particle Technology Forum