Dopant screening of modified Fe2O3 oxygen carriers in chemical looping hydrogen production

Effect of support on hydrogen generation over iron oxides in the chemical looping process

“…Many metal oxides have been proposed and used as oxygen carriers to generate hydrogen, including NiO, 19 CuO, 20 and Fe 2 O 3 . 21 Fe 2 O 3 is recognized as the most prospective candidate among the metal oxides for its low cost, 22 abundance in nature, 23 and environmental compatibility. 24 However, the grains of pure iron oxides tend to aggregate on the surface and contribute to serious sintering in the first few cycles, thus leading to a rapidly deteriorated performance.…”

Feasibility Study of an Iron-Based Composite Added with Al2O3/ZrO2 as an Oxygen Carrier in the Chemical Looping Applications

“…In addition, either iron oxides or alumina did not have any interaction with zirconia, which meant no second phase could be found in the operating temperature around 900 • C, presented in the phase diagram [29,30]. Further, some researchers suggested that the addition of Zr can enhance Fe 2 O 3 's ability to deeply reduce to FeO which could promote the efficiency of hydrogen generation [31]. Furthermore, Zirconia has a similar thermal expansion coefficient to iron oxides compared to alumina (Al 2 O 3 ∼ = 7.2 × 10 −6 K −1 , ZrO 2 ∼ = 10.5 × 10 −6 K −1 , and Fe 2 O 3 , Fe 3 O 4 , FeO and Fe ∼ = 8-15 × 10 −6 K −1 ), which could help to reduce the thermal stress during the redox reaction [32,33].…”

Thermodynamic guiding principles of high-capacity phase transformation materials for splitting H2O and CO2 by thermochemical looping

“…Commonly investigated reducing agents include coal and natural gas. 28,36–41 CO 2 emission from the reduction reaction needs to be avoided by measures like CO 2 capture and sequestration to achieve GHG-free splitting of water/CO 2 . Taking CH 4 as an example:…”