1000/1000
Hot
Most Recent
The thermochemical water-splitting method is a promising technology for efficiently converting renewable thermal energy sources into green hydrogen. Thermochemical water splitting uses a high-temperature source, e.g., nuclear energy, waste heat, or concentrated solar systems, to convert water into hydrogen and oxygen through cyclic chemical reactions. Several promising routes have been proposed for hydrogen production through green technologies such as biological processes (such as CO gas-fermentation, dark fermentation, etc.), electrical (such as alkaline electrolysis cell, anion exchange membrane electrolysis cell, proton exchange membrane electrolysis cell, solid oxide electrolysis cell, etc.), photonic (bio-photolysis, photofermentation, etc.), thermochemical, etc.
Cycle | Major Discovery | Ref. |
---|---|---|
S-I | Optimization of the Bunsen section for liquid–liquid separation. Increasing iodine content improved separation characteristics. The optimum I2/H2SO4 ratio was in the range of 2.45–3.99 at 70–85 °C |
[63] |
S-I | Developed a microporous membrane resistant to sulfur trioxide composed of α-alumina support, ZrO2-SiO2 intermediate layer, and organosilica sol top layer. High Si:Zr ratio and large pore of the ZrO2-SiO2 showed higher O2/SO3 selectivity and higher chemical stability against SO3 | [64] |
S-I | Developed a modified cycle with fewer steps and used a steam boiler. The modified cycle has a higher HI decomposition rate, and the Bunsen reaction happened at lower temperatures. | [65] |
S-I | Catalysts with hierarchical pore structure and higher specific surface area and micropore proportion of about 50% showed higher catalytic activity. | [66] |
S-I | N doping promotes HI decomposition rate | [67] |
HyS | Increasing Fe content in Fe/Al and Fe/Ti binary metal oxide catalysts improved catalytic activity | [68] |
HyS | Cr, Ce, U, Mn, and Ni form stable sulphates and are not suitable catalysts for sulfuric acid decomposition. t/BaSO4-TiO2, Pt/TiO2, Pt/ZrO2, and Pt/SiO2 are the most suitable catalysts for the HyS cycle. | [69] |
HyS | PtxPdy thin film deposited on a Si wafer showed high catalytic activity | [70] |
HyS | Increasing Ni dopant in PtxNiy/C catalysts increased electron vacancies and improved catalytic performance | [71] |
HyS | Incorporating ceria in Pt/C composite catalyst increased catalyst active area and improved its performance | [72] |
Cu-Cl | Developing a novel integrated system for producing nitrogen, methane, ammonia, oxygen, and carbon dioxide | [73] |
Cu-Cl | Optimizing the temperature of the hydrolysis step can minimize the number of byproducts. | [74] |
Cu-Cl | Cu-Cl is the most promising cycle for large-scale hydrogen production. | [75] |
ZnO/Zn | Partially reduced ZnO showed higher catalytic performance at elevated temperatures (R = 57.2%) | [76] |
ZnO/Zn | Hindered recombination and lowered the reaction temperature of the first step (methane or carbon as reducing agent) | [77] |
ZnO/Zn | A negative axial temperature gradient reduced the steam and inert gas proportion | [78][79] |
SnO2/SnO | Reducing O2 partial pressure to about 10−3 bar decreased thermal reduction temperature | [80] |
Fe3O4/FeO | Non-stoichiometric wustite have higher defect densities and showed higher reaction rates | [81] |
Ferrite | Zirconia support enhances the energy radiation absorption and lowers the temperature | [82] |
Ferrite | Ceramics nanoparticles can slightly increase hydrogen yield and hinder grain growth | [83] |
Ferrite | ZrO2 can reduce the high-temperature sintering and improve catalytic activity | [84] |
Ferrite | Calcium-stabilized zirconia forms calcium zirconate promotes high active phase dispersion and improves hydrogen yield | [85] |
Ferrite | Sacrificial (carbon black and PEG) and zirconia plates improved the thermal stability of Ni-ferrite samples | [84] |
Ferrite | Core-shell NiFe2O4/Y2O3 nanoparticles showed stable hydrogen volume, but lower rates of hydrogen production than that of mixed powders | [83] |
Ferrite | Hercynite formation in alumina and cobalt ferrite decreased ferrite reduction temperature | [86] |