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Pai, Mrinal R.; Wani, B.N.; Gupta, Nandini

doi:10.1023/a:1016512217141

Cited by 12 publications

(2 citation statements)

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“…The layers of chains are stacked along the c-axis, which are connected by neptunium atoms in the unit cell. Recently, we had reported the catalytic behavior of Th(VO 3 ) 4 and its aliovalent substituted derivatives for oxidation of carbon monoxide, methanol [18,19]. The enhancement of the catalytic activity is found to have a close correlation with the lattice defect generated by aliovalent substitutions in Th(VO 3 ) 4 .…”

Section: Introductionmentioning

confidence: 97%

Crystal structure of thorium metavanadate (Th(VO3)4)

Achary

Pai

Mishra

et al. 2008

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 97%

Crystal structure of thorium metavanadate (Th(VO3)4)

Achary

Pai

Mishra

et al. 2008

Journal of Alloys and Compounds

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“…Earlier, we have reported structure−activity correlations and thermophysical properties of Th(VO 3 ) 4 , LaMnO 3 , In 2 Ti 1− x Fe x O 5-δ , In 2 Ti 1− x Cr x O 5-δ (0.0 ≤ x ≤ 0.02), etc., mixed metal oxides catalysts. − We have dealt in detail elsewhere with the preparation and characterization by X-ray diffraction (XRD), N 2 -BET, FTIR, scanning electron microscopy (SEM), Mössbauer spectroscopy, and temperature-programmed reduction (TPR) profiles of Fe-substituted oxygen excess layered perovskites, lanthanum titanates, La 2 Ti 2(1− x ) Fe 2 x O 7-δ . The consequences of iron substitution in the crystal lattice of lanthanum titanate, rather than being dispersed for the N 2 O reduction by CO and also knowing the intermediates produced in the course of the reaction, have yet to be verified.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of CO + N₂O Reaction via Transient CO₃²⁻ Species over Crystalline Fe-Substituted Lanthanum Titanates

et al. 2010

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Some newer mechanistic aspects investigated by in situ Fourier transform infrared (FTIR) in conjunction with catalytic activity under similar conditions over crystalline lanthanum titanates as a function of Fe substitution at the B-site for the CO + N(2)O reaction are reported for the first time in the present communication. La(2)Ti(2(1-x))Fe(2x)O(7-delta) (0.0 < or = x < or = 1.0) was synthesized by gel combustion where Fe(3+) substitution effectively enhanced the conversion rates for N(2)O reduction as compared to the pristine La(2)Ti(2)O(7) (LTOGC). Among all samples, maximum conversion over La(2)Ti(0.8)Fe(1.2)O(7-delta) [LF(0.6)GC] catalyst was observed. In situ FTIR results reveal that substitution-induced anionic vacancies/defects provide additional sites on the surface of LF(0.6)GC for CO chemisorptions, whereas a perfect stoichiometric lattice like LTOGC is devoid of such sites. Surface-adsorbed CO reacts with surface lattice oxygen in the case of nonstoichiometric LF(0.6)GC to produce carbonates (M-CO(3)(2-)) at a much lower temperature. The reaction proceeds via carbonate formation, leaving the catalytic surface oxygen deficient in LF(0.6)GC, and therefore facilitates the reduction of preadsorbed, N(2)O [N(2)O(g) + * --> N(2) + *-O) by easily adsorbing the oxygen species (*-O) generated in N(2)O reduction, which is subsequently driven away by adsorbed/gas phase CO, whereas in the case of LTOGC, progress of the reaction was sluggish in the absence of transient carbonate species. Dissociative chemisorptions of N(2)O are not facilitated on stoichiometric oxygen excess titanate, as there is no vacancy in the surface to accommodate another oxygen atom. The redox mechanism via CO(3)(2-) species is proposed for CO + N(2)O reaction over La(2)Ti(2(1-x))Fe(2x)O(7-delta), as against the associative mechanism observed in the unsubstituted sample, La(2)Ti(2)O(7), as suggested by in situ FTIR in conjunction with catalytic activity results.

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