New insight into the grafted transition metal ions in trilacunary Keggin polyoxometalates dopants for efficient and stable perovskite solar cells

2021 ◽  
Vol 504 ◽  
pp. 230073
Author(s):  
Xiao Fan ◽  
Jian Zhang ◽  
Yulin Yang ◽  
Debin Xia ◽  
Yayu Dong ◽  
...  
Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1399
Author(s):  
Silva Stanchovska ◽  
Georgy Ivanov ◽  
Sonya Harizanova ◽  
Krasimir Tenchev ◽  
Ekaterina Zhecheva ◽  
...  

Elaboration of Pd-supported catalysts for catalytic combustion is, nowadays, considered as an imperative task to reduce the emissions of methane. This study provides new insight into the method of deposition, chemical state of Pd and oxygen storage capability of transition metal ions and their effects on the catalytic reactivity of supported catalysts for the combustion of methane. The catalyst with nominal composition La(Co0.8Ni0.1Fe0.1)0.85Pd0.15O3 was supported on SiO2-modified/γ-alumina using two synthetic procedures: (i) aerosol assisted chemical vapor deposition (U-AACVD) and (ii) wet impregnation (Imp). A comparative analysis shows that a higher catalytic activity is established for supported catalyst obtained by wet impregnation, where the PdO-like phase is well dispersed and the transition metal ions display a high oxygen storage capability. The reaction pathway over both catalysts proceeds most probably through Mars–van Krevelen mechanism. The supported catalysts are thermally stable when they are aged at 505 °C for 120 h in air containing 1.2 vol.% water vapor. Furthermore, the experimentally obtained data on La(Co0.8Ni0.1Fe0.1)0.85Pd0.15O3—based catalyst, supported on monolithic substrate VDM®Aluchrom Y Hf are simulated by using a two-dimensional heterogeneous model for monolithic reactor in order to predict the performance of an industrial catalytic reactor for abatement of methane emissions.


RSC Advances ◽  
2014 ◽  
Vol 4 (56) ◽  
pp. 29702-29714 ◽  
Author(s):  
Yan Li ◽  
Yiming Jia ◽  
Zhenwen Wang ◽  
Xianghui Li ◽  
Wen Feng ◽  
...  

Disruption of intramolecular H-bonding via N-substitution leads to rotational isomerization and much improvement in extraction of Hg2+.


Fuel ◽  
2022 ◽  
Vol 312 ◽  
pp. 123002
Author(s):  
Nail R. Khafizov ◽  
Timur I. Madzhidov ◽  
Chengdong Yuan ◽  
Mikhail A. Varfolomeev ◽  
Oleg N. Kadkin

Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.


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