Cobalt supported on zirconia and sulfated zirconia I. FT-IR spectroscopic characterization of the NOx species formed upon NO adsorption and NO/O2 coadsorption

Kantcheva, Margarita; Vakkasoglu, Ahmet S.

doi:10.1016/j.jcat.2004.02.007

Cited by 117 publications

(69 citation statements)

References 38 publications

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“…It has been reported that the bands between 1200 and 870 cm −1 are attributed to the stretching vibrations of S-O. 48 Therefore, based on the FT-IR, it can be confirmed that SZ exists in the MIL-101s which is in agreement with the results of the elemental analysis for sulfur content and acid site density. The SEM images (Figure 6) of the SZ/MIL101s show that the morphologies of the SZ/MIL-101s are homogeneous even with the composing of MIL-101 with SZ.…”

Section: Resultssupporting

confidence: 82%

Preparation of a Composite of Sulfated Zirconia/Metal Organic Framework and its Application in Esterification Reaction

Park¹,

Ḥasan²,

Ahmed³

et al. 2014

Bulletin of the Korean Chemical Society

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A porous metal-organic framework (MOF), MIL-101, was synthesized in the presence of sulfated zirconia (SZ) to produce acidic SZ/MIL-101 composites for the first time. The composites were characterized with XRD, nitrogen adsorption, FT-IR, scanning electron microscope, chemical analysis and so on. The composites (SZ/ MIL-101s) were successfully applied in a liquid-phase esterification for a high yield of ester. This catalytic result of SZ/MIL-101, compared with that of pure SZ or MIL-101 (showing a negligible yield of ester), suggests that the SZ in the composite is highly active in the acid catalysis probably because of the welldispersed active species of SZ. Moreover, the esterification is catalyzed in heterogeneous mode as confirmed by negligible esterification after filtration of the catalyst. Finally, microwaves can be efficiently applied both in the synthesis of the composites and the esterification reaction to accelerate the two processes of synthesis and esterification by about 5 times.

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Section: Resultssupporting

confidence: 82%

Preparation of a Composite of Sulfated Zirconia/Metal Organic Framework and its Application in Esterification Reaction

Park¹,

Ḥasan²,

Ahmed³

et al. 2014

Bulletin of the Korean Chemical Society

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“…4a. The spectral region between 1700 and 1200 cm −1 is characteristic for the nitrate and nitrite species coordinated on TiO 2 and ZrO 2 [28][29][30]. The observed frequencies at 1644 and 1209 cm −1 can be attributed to bridging nitrates, while the features at 1578, 1550 and 1280 cm −1 can be assigned to bidentate nitrates [8,31].…”

Section: Structural Characterization Of the Synthesized Materialsmentioning

confidence: 93%

NOx storage and reduction pathways on zirconia and titania functionalized binary and ternary oxides as NOx storage and reduction (NSR) systems

2014

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a b s t r a c tBinary and ternary oxide materials, ZrO 2 /TiO 2 (ZT) and Al 2 O 3 /ZrO 2 /TiO 2 (AZT), as well as their Ptfunctionalized counterparts were synthesized and characterized via XRD, Raman spectroscopy, BET, in situ FTIR and TPD techniques. In the ZT system, a strong interaction between TiO 2 and ZrO 2 domains at high temperatures (>973 K) resulted in the formation of a low specific surface area (i.e. 26 m 2 /g at 973 K) ZT material containing a highly ordered crystalline ZrTiO 4 phase. Incorporation of Al 2 O 3 in the AZT structure renders the material highly resilient toward crystallization and ordering. Alumina acts as a diffusion barrier in the AZT structure, preventing the formation of ZrTiO 4 and leading to a high specific surface area (i.e. 264 m 2 /g at 973 K). NO x adsorption on the AZT system was found to be significantly greater than that of ZT, due to almost ten-fold greater SSA of the former surface. While Pt incorporation did not alter the type of the adsorbed nitrate species, it significantly boosted the NO x adsorption on both Pt/ZT and Pt/AZT systems. Thermal stability of nitrates was higher on the AZT compared to ZT, most likely due to the defective structure and the presence of coordinatively unsaturated sites on the former surface. Pt sites also facilitate the decomposition of nitrates in the absence of an external reducing agent by shifting the decomposition temperatures to lower values. Presence of Pt also enhances partial/complete NO x reduction in the absence of an external reducing agent and the formation of N 2 and N 2 O. In the presence of H 2 (g), reduction of surface nitrates was completed at 623 K on ZT, while this was achieved at 723 K for AZT. Nitrate reduction over Pt/ZT and Pt/AZT via H 2 (g) under mild conditions initially leads to conversion of bridging nitrates into monodentate nitrates/nitrites and the formation of surface OH and NH x functionalities. N 2 O(g) was also continuously generated during the reduction process as an intermediate/byproduct.

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“…Many elements supported on SZ have been shown to be active for the CH 4 -SCR reaction, including Ga [5], Pd [6][7][8][9], Rh [10], Co [11], Mn [12], and In [13]. Current research efforts have focused on the mechanism of the reactions over these catalyst [14][15][16] and on the improvement of the reaction activity of these catalyst by co-loading these element onto the SZr support, such as PdCo/SZr [17,18]. 2000, Chin et al reported on the high activity of a Pd/WZr catalyst and its high resistance to H 2 O and SO 2 for the reaction [19,20].…”

Section: Introductionmentioning

confidence: 99%

Selective Catalytic Reduction of NOx with CH4 over the In/Sulfated TiO2 Catalyst

Yang

Wen

et al. 2007

Catal Lett

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Tungstated TiO 2 (WTi), tungstated Fe 2 O 3 (WFe), tungstated SnO 2 (WSn), sulfated TiO 2 (STi), sulfated Fe 2 O 3 (SFe), and sulfated SnO 2 (SSn) are used as the support for the In and Pd catalysts for the SCR of NO with methane. It was found that the In/STi catalyst with a 2% indium loading showed the highest NO x conversion (39% at 450°C and 12,000 h -1 ) among all of the catalysts studied. The acid strength of the STi support was very important for the formation of the InO + site, which was thought to be the active site for NO reduction. The activity of the In/STi catalyst can be improved by increasing the surface area of the STi support. The most attractive feature of the In/STi catalyst is its high resistance for SO 2 .

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Cobalt supported on zirconia and sulfated zirconia I. FT-IR spectroscopic characterization of the NOx species formed upon NO adsorption and NO/O2 coadsorption

Cited by 117 publications

References 38 publications

Preparation of a Composite of Sulfated Zirconia/Metal Organic Framework and its Application in Esterification Reaction

Preparation of a Composite of Sulfated Zirconia/Metal Organic Framework and its Application in Esterification Reaction

NOx storage and reduction pathways on zirconia and titania functionalized binary and ternary oxides as NOx storage and reduction (NSR) systems

Selective Catalytic Reduction of NOx with CH4 over the In/Sulfated TiO2 Catalyst

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