BaTiO3 and PbTiO3 perovskite as catalysts for methane combustion

Popescu, Ionel; Urdă, Adriana; Yuzhakova, Tatiana; Marcu, Ioan–Cezar; Kovács, József; Săndulescu, Ioan

doi:10.1016/j.crci.2008.09.006

Cited by 22 publications

(16 citation statements)

References 15 publications

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“…The apparatus and the conditions have been described elsewhere [8]. The reaction mixture consisted of 5% (vol.)…”

Section: Catalytic Testmentioning

confidence: 99%

“…BaTiO 3 and PbTiO 3 catalysts were prepared through solid state reactions as described earlier [8]. Thus, the starting materials Ba(NO 3 ) 2 , PbO and TiO 2 were weighed out in stoichiometric proportion to form the desired composition and mechanically mixed for 1 h in a mechanical mortar.…”

Section: Catalysts Preparation and Characterizationmentioning

confidence: 99%

“…species, caused by the introduction of increasing amounts of Fe in the lattice, led to a proportionally higher activity. Consequently, this technique was applied to barium and lead perovskites, active catalysts in the total oxidation of methane [8].…”

Section: Introductionmentioning

confidence: 99%

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Study of the Catalytic Activity–Semiconductive Properties Relationship For BaTiO3 and PbTiO3 Perovskites, Catalysts for Methane Combustion

et al. 2011

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The electrical conductivity of barium and lead perovskites used as catalysts for the total oxidation of methane, has been measured under nitrogen, methanenitrogen mixture, air and methane-air mixture (reaction mixture) at the catalytic reaction temperature. The two compounds appeared to be p-type semiconductors under air with positive holes as the main charge carriers but became n-type when contacted with methane-nitrogen mixture. Their conductivities differ by 1.5 orders of magnitude as n-type semiconductors and by three orders of magnitude when being p-type semiconductors. These results explained the difference in the catalytic activity encountered on the two solids. The alkane activation was proposed to be related in both cases to the p-type semiconducting properties of the solids, likely through hydrogen abstraction by a surface O -species, forming a CH 3• radical. The overall reaction mechanism on both perovskites can be assimilated to a Mars and van Krevelen mechanism.

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“…The apparatus and the conditions have been described elsewhere [8]. The reaction mixture consisted of 5% (vol.)…”

Section: Catalytic Testmentioning

confidence: 99%

Section: Catalysts Preparation and Characterizationmentioning

confidence: 99%

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Study of the Catalytic Activity–Semiconductive Properties Relationship For BaTiO3 and PbTiO3 Perovskites, Catalysts for Methane Combustion

et al. 2011

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“…19 The adsorption of atoms and molecules on BTO surfaces is an important topic; perovskites have been shown to be effective catalysts for removing CO and CH 4 , 25 and BTO is a particularly effective catalyst for the combustion of CH 4 . 26 Prior research shows that the adsorption of H 2 O on the TiO 2 -terminated (001)BTO surface leads to disassociation into H + and OH -groups, 27,28 and ~20% of Ti surface atoms have these OH -groups; the OH -adsorbed on Ti is enough to reverse the polarization of the surface TiO 2 layer. 27 Adsorption of H 2 O on the BaO-terminated surface leads to surface O vacancies, Ba(OH) 2 groups, and reversal of the surface polarization.…”

Section: Introductionmentioning

confidence: 99%

Surface-hydrogen-induced metallization and rumpling in thin BaTiO3 films

Fredrickson

Demkov

2016

Phys. Rev. B

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We study theoretically metallization and polarization enhancement effects of H adsorption at the TiO 2 -terminated (001) BaTiO 3 surface. The clean BaTiO 3 slab does not polarize, because the slab is too thin to support a ferroelectric state. We find that the metallization of the surface is a strong function of hydrogen coverage, and that the insulating surfaces do not support a rumpling or polarization in BTO films, whereas all metallic surfaces do so. The donated charge from the adsorbed H transforms the TiO 2 into a metallic capping layer, stabilizing the ferroelectric state.

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“…Therefore, there has been much interest in the development of catalysts based on mixtures of selected metal oxides instead of noble metals. Perovskitelike mixed oxides, with general formula ABO 3 , showed suitable catalysts for oxidation of light hydrocarbons and, in particular, of methane [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES

Pecchi

Jiliberto

Delgado

2011

J. Chil. Chem. Soc.

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The reaction kinetics of methane combustion over La 1-x Ca x FeO 3 perovskites (x=0.0, 0.2, 0.4) was studied. The results show that the catalytic activity is higher in the calcium-doped perovskites. It is found that this higher catalytic activity is related to a lower activation energy. The value of the activation energy is not affected by the level of Ca-doping. The observed difference in the catalytic activity between the doped perovskites is interpreted as a consequence of the so-called compensatory effect, i.e., a larger pre-exponential factor which results from the higher number of active sites promoted by defect reactions triggered by the substitution of lanthanum by calcium. The substitution of lanthanum by a lower valence cation, as calcium, entails both the formation of oxygen vacancies and oxidation of some iron ions from Fe 3+ to Fe 4+, in order to preserve the electroneutrality. The oxygen vacancies account for the increasing participation of lattice oxygen in the combustion kinetics as the calcium doping increases. The experimental results were satisfactorily fitted to the Rideal-Elay mechanism.

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BaTiO3 and PbTiO3 perovskite as catalysts for methane combustion

Cited by 22 publications

References 15 publications

Study of the Catalytic Activity–Semiconductive Properties Relationship For BaTiO3 and PbTiO3 Perovskites, Catalysts for Methane Combustion

Study of the Catalytic Activity–Semiconductive Properties Relationship For BaTiO3 and PbTiO3 Perovskites, Catalysts for Methane Combustion

Surface-hydrogen-induced metallization and rumpling in thin BaTiO3 films

REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES

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