Solar thermochemical fuel production from H2O and CO2 splitting via two-step redox cycling of reticulated porous ceria structures integrated in a monolithic cavity-type reactor

We propose a novel solar thermochemical receiver–reactor array concept for hydrogen production via ceria redox cycling. The receiver–reactor array can improve the solar-to-fuel efficiency by realizing the heat recuperation, reduction, and oxidation processes synchronously. A linear matrix model and a lumped parameter model are developed to predict thermal performance of the new solar thermochemical system. The system thermal performance is characterized by heat recovery effectiveness of solid-phase and solar-to-fuel efficiency. Investigated parameters include reduction temperature, oxygen partial pressure, number of receiver–reactors, concentration ratio, and gas-phase heat recovery effectiveness. For baseline conditions, the solid-phase heat recovery effectiveness and the solar-to-fuel efficiency are found to be 81% and 27%, respectively. For perfect gas-phase heat recovery and a solar concentration ratio of 5,000, the solar-to-fuel efficiency exceeds 40%.

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Effects of Dopant Metal Variation and Material Synthesis Method on the Material Properties of Mixed Metal Ferrites in Yttria Stabilized Zirconia for Solar Thermochemical Fuel Production

International Journal of Photoenergy ◽

10.1155/2015/856385 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Jeffrey Leonard ◽

Nichole Reyes ◽

Kyle M. Allen ◽

Kelvin Randhir ◽

Like Li ◽

...

Keyword(s):

Synthesis Method ◽

Yttria Stabilized Zirconia ◽

Synthesis Process ◽

Synthesis Methods ◽

Stabilized Zirconia ◽

Fuel Production ◽

Solid State Method ◽

Wet Chemistry ◽

Mixed Metal ◽

Solar Thermochemical

Mixed metal ferrites have shown much promise in two-step solar-thermochemical fuel production. Previous work has typically focused on evaluating a particular metal ferrite produced by a particular synthesis process, which makes comparisons between studies performed by independent researchers difficult. A comparative study was undertaken to explore the effects different synthesis methods have on the performance of a particular material during redox cycling using thermogravimetry. This study revealed that materials made via wet chemistry methods and extended periods of high temperature calcination yield better redox performance. Differences in redox performance between materials made via wet chemistry methods were minimal and these demonstrated much better performance than those synthesized via the solid state method. Subsequently, various metal ferrite samples (NiFe2O4, MgFe2O4, CoFe2O4, and MnFe2O4) in yttria stabilized zirconia (8YSZ) were synthesized via coprecipitation and tested to determine the most promising metal ferrite combination. It was determined that 10 wt.% CoFe2O4in 8YSZ produced the highest and most consistent yields of O2and CO. By testing the effects of synthesis methods and dopants in a consistent fashion, those aspects of ferrite preparation which are most significant can be revealed. More importantly, these insights can guide future efforts in developing the next generation of thermochemical fuel production materials.

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