Kinetic investigations of the hydrogen production step of a thermochemical cycle using mixed iron oxides coated on ceramic substrates

2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Martina Neises ◽  
Martin Roeb ◽  
Martin Schmücker ◽  
Christian Sattler ◽  
Robert Pitz-Paal
Keyword(s):  
Hydrogen Production ◽  
Iron Oxides ◽  
Thermochemical Cycle ◽  
Ceramic Substrates ◽  
Kinetic Investigations

Investigations of the Regeneration Step of a Thermochemical Cycle Using Mixed Iron Oxides Coated on SiSiC Substrates

2011 ◽  
Author(s):  
Martina Neises ◽  
Heike Simon ◽  
Martin Roeb ◽  
Martin Schmu¨cker ◽  
Christian Sattler ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Hydrogen Production ◽  
Laboratory Test ◽  
Iron Oxides ◽  
Small Scale ◽  
Thermochemical Cycle ◽  
Test Rig ◽  
Regeneration Time ◽  
Eds Analysis ◽  
Parametric Studies

A two-step thermochemical cycle for hydrogen production using mixed iron oxides coated on silicon carbide substrates has been investigated. The water-splitting step proceeds at temperatures between 800 and 1000 °C while for the regeneration step temperatures around 1200 °C are needed. A deactivation of the material resulting in a decrease of the hydrogen production within the first couple of cycles was observed in preceding tests. For detailed investigations of the system composed of the redox-material and the substrate small scale samples were tested in a laboratory test-rig. For identification of material changes the samples were investigated via XRD and SEM-EDS analysis. The analysis revealed the reasons for the deactivation of the redox-material. Through parametric studies the influence of the regeneration parameters, namely regeneration temperature and time on the hydrogen production was analysed. A model for the regeneration step was developed describing the performance of the regeneration step as a function of temperature and time and additionally as a function of total regeneration time, i.e. the cumulated time the sample has been regenerated.

Electrophoretic Deposition of Nanoparticles as Electrocatalysts for Electrolysis in the Solar Sulfur Ammonia Hydrogen Production

2015 ◽  
Vol 654 ◽  
pp. 76-82
Author(s):  
Nicole S. Pacheco ◽  
Neil Verma ◽  
Komail Haider ◽  
Jan B. Talbot
Keyword(s):  
Hydrogen Production ◽  
Ammonium Sulfate ◽  
Electrophoretic Deposition ◽  
Electrocatalytic Activity ◽  
Cobalt Ferrite ◽  
Ferrite Nanoparticles ◽  
Thermochemical Cycle ◽  
Cobalt Ferrite Nanoparticles ◽  
Ammonium Sulfite

Cobalt ferrite nanoparticles were deposited using electrophoretic deposition from two different bath chemistries, 90 vol.% water and 10 vol.% isopropanol with hexadecyltrimethlyammonium bromide (CTAB) and 100 % ethanol. The deposits were tested for electrocatalytic activity for the oxidation of ammonium sulfite to ammonium sulfate as part of a solar sulfur ammonia thermochemical cycle to produce hydrogen.

Hydrogen production via a novel two-step solar thermochemical cycle based on non-volatile GeO2

Solar Energy ◽  
2019 ◽  
Vol 179 ◽  
pp. 30-36 ◽  
Author(s):  
Mingkai Fu ◽  
Tianzeng Ma ◽  
Lei Wang ◽  
Shaomeng Dai ◽  
Zheshao Chang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Thermochemical Cycle ◽  
Solar Thermochemical

Reactive Pellets for Improved Solar Hydrogen Production Based on Sodium Manganese Ferrite Thermochemical Cycle

2008 ◽  
Author(s):  
Carlo Alvani ◽  
Mariangela Bellusci ◽  
Aurelio La Barbera ◽  
Franco Padella ◽  
Marzia Pentimalli ◽  
...  
Keyword(s):  
High Temperature ◽  
Hydrogen Production ◽  
Water Splitting ◽  
Sodium Carbonate ◽  
Production Efficiency ◽  
Manganese Carbonate ◽  
Reactive System ◽  
Thermochemical Cycle ◽  
Manganese Ferrite ◽  
Oxide Mixture

Hydrogen production by water-splitting thermochemical cycle based on manganese ferrite /sodium carbonate reactive system is reported. Two different preparation procedures for manganese ferrite/sodium carbonate mixture were adopted and compared in terms of materials capability to cyclical hydrogen production. According to the first procedure conventionally synthesized manganese ferrite, i. e. high temperature (1250 °C) heating in Ar of carbonate/oxide precursors, was mixed with sodium carbonate. The blend was tested inside a TPD reactor using a cyclical hydrogen production/material regeneration scheme. After few cycles the mixture resulted rapidly passivated and unable to further produce hydrogen. An innovative method that avoids the high temperature synthesis of manganese ferrite is presented. This procedure consists in a set of consecutive thermal treatments of a manganese carbonate/sodium carbonate/iron oxide mixture in different environments (inert, oxidative, reducing) at temperatures not exceeding 750 °C. Such material, whose observed chemical composition consists in manganese ferrite and sodium carbonate in stoichiometric amount, is able to evolve hydrogen during 25 consecutive water-splitting cycles, with a small decrease in cyclical production efficiency.

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