A heterogeneous single Cu catalyst of Cu atoms confined in the spinel lattice of MgAl2O4 with good catalytic activity and stability for NO reduction by CO

A heterogeneous single Cu catalyst exhibits good catalytic activity and durability at high temperature for NO reduction by CO due to the confinement effect of spinel lattice.

Influence of Zinc Injection on Dose Rate from Primary System Loops for PWR Units and Predictive Assessments for VVER-1000

The paper analyzed the advisability of zinc injection into the VVER primary system coolant in order to minimize radioactive fields of equipment. In the western NPPs with PWR, zinc injection into the coolant leads to permanent decrease of dose rates caused by radioactive cobalt. Zinc is introduced into the oxide film on the primary system equipment surfaces to form the most stable zinc spinel, which prevents the further introduction of radioactive cobalt in the oxide film. Predictive assessments for VVER-1000 show that under the zinc concentration of µg/dm3 in the coolant, cation vacancies in the spinel lattice will be occupied mostly by zinc, preventing the penetration of cobalt in the spinel and increase of radioactive fields of equipment.

Boosting electrochemical water oxidation through replacement of Oh Co sites in cobalt oxide spinel with manganese

Effect of substitution in the spinel lattice, structure–activity relation and nature of active species involved during oxygen evolution reaction were uncovered in the manganese cobalt oxide (MCO).

BaMn9II(VO4)6(OH)2: a homospin ferrimagnet with a broken spinel-lattice of B-sites

A new homospin ferrimagnet BaMn9II(VO4)6(OH)2 exhibits a unique structural feature with a reverse triangular dipyramid Mn7 spin lattice, in which such a lattice can be considered as a broken spin lattice of B-sites in spinel compounds.

Microstructure Characterization of Nanocrystalline Magnesium Ferrite Annealed at Elevated Temperatures by Rietveld Method

Nanocrystalline magnesium ferrite is synthesized at room temperature by high energy ball milling the MgO and α-Fe2O3 (1 : 1 mol fraction) powders. The Rietveld structure and microstructure refinements of X-ray powder diffraction data of 9 h milled sample reveal the presence of mixed and nearly inverse spinel nanocrystalline Mg-ferrite phases. Postannealing of nanocrystalline powder within 873–1473 K reveals continuous change in cation distribution among the tetrahedral and octahedral sites of mixed spinel lattice leading to nearly inverse spinel structure with increasing temperature. Mixed spinel structure finally transformed into inverse spinel structure after 1 h of annealing at 1073 K. The ferrite phase becomes completely stoichiometric by solid-state diffusion of unreacted (∼0.3 mol fraction) α-Fe2O3 into spinel lattice after 1 h of annealing at 1273 K. Interestingly, particle sizes of ferrite phases do not increase considerably up to 1073 K and increase suddenly after transformation of mixed spinel into nearly inverse spinel structure.