Trends in the phase stability and thermochemical oxygen exchange of ceria doped with potentially tetravalent metals

Abstract

Screening of tetravalent dopants correlates dopant radius and oxygen exchange capacity for ceria optimization in solar thermochemical CO2 reduction.

High performance cork-templated ceria for solar thermochemical hydrogen production via two-step water-splitting cycles

“…Therefore, the effect of dopants on ceria to facilitate solar thermochemical gas splitting cycles needs to be re-evaluated. 44,45 When O-vacancies form, each removed O 2− anion releases two electrons to the ceria bulk; these electrons localize on two Ce 4+ reducing them to Ce 3+ cations: Taking into account the peak H 2 production rate obtained for CG19 (and high heating value of H 2 =286 kJ/mol), the maximum η solar−to−fuel was estimated to be 0.34% (for 1 kW solar thermal power input absorbed in the solar reactor), while average efficiencies were about 0.28% for CG and 0.21% for CF materials. These values for a real lab-scale on-sun reactor system are quite low given the low amount of processed ceria in the solar tubular reactor and could thus be enhanced by both increasing the oxide mass loading and up-scaling the reactor (inherently reducing heat losses).…”

Preparative History vs Driving Force in Water Oxidation Catalysis: Parameter Space Studies of Cobalt Spinels

“…A variation of the sol–gel method from ref (98) was applied: 1.8 mmol Co(NO 3 ) 2 ·6H 2 O and 2.7 mmol citric acid were dissolved in 25 mL of H 2 O. The solution was heated up slowly while stirring until a gel was formed.…”

Solar Redox Cycling of Ceria Structures Based on Fiber Boards, Foams, and Biomimetic Cork-Derived Ecoceramics for Two-Step Thermochemical H2O and CO2 Splitting

“…5 Ceria is currently designated as the benchmark material to perform thermochemical cycles, given its ability to maintain its crystallographic structure over a large range of non-stoichiometry, together with its thermodynamically favorable oxidation and high oxygen storage capacity, which makes it suitable to perform thermochemical cycles with high performance stability. Numerous studies have been devoted to ceria [6][7][8][9][10][11][12][13][14] , and the addition of dopants [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] to enhance its redox performance. However, ceria redox activity depends on the reduction temperature and oxygen partial pressure applied during the high-temperature step, which is generally limited to 1500°C due to undesired oversintering and ceria sublimation.…”