Low temperature catalytic NOx–H2 reactions over Pt/TiO2-ZrO2 in an excess oxygen

Machida, Masato; Ikeda, Satoshi; Kurogi, Daisuke; Kijima, Toshiki

doi:10.1016/s0926-3373(01)00243-0

Cited by 134 publications

(86 citation statements)

References 22 publications

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“…It is known that fixation of NO in the presence of excess O 2 on noble metals as well as support oxides occurs in form of surface nitrates which are reactive towards H 2 [6]. By dissociation of H 2 , the noble metal supplies H which reacts with nitrates species located on the support.…”

Section: Mechanism Considerationmentioning

confidence: 99%

“…Subsequently, Pt/SiO 2 [4,5], Pt/TiO 2 -ZrO 2 [6], Pt/La 0.5 Ce 0.5 MnO 3 [7], Pt/ MFI [8,9] and Pt/Mg-Al-O [10] have been reported to be promising catalysts for H 2 -SCR reaction. More recently, supported palladium catalysts, such as Pd/TiO 2 [11], Pd/Al 2 O 3 [12], Pd/V 2 O 5 /Al 2 O 3 [13] and Pd/TiO 2 /Al 2 O 3 [14] are also reported to be highly active in H 2 -SCR reaction.…”

Section: Introductionmentioning

confidence: 99%

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NO selective reduction by hydrogen on potassium titanate supported palladium catalyst

Zhang

Guan

et al. 2008

Catalysis Communications

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a b s t r a c tPotassium titanate (K 2 O-6TiO 2 ) nanowires were successfully prepared by alkali treatment of TiO 2 (79% anatase, 21% rutile) under autogenous pressure in a Teflon-lined autoclave at 200°C. After further modification with 1 wt.% Pd by wet impregnation, the calcined and pre-reduced Pd/K 2 O-6TiO 2 catalyst was applied for selective reduction of NO x by H 2 (H 2 -SCR) under lean conditions, together with Pd/Al 2 O 3 and Pd/TiO 2 as reference. The reference catalysts exhibited maximum NO conversion of about 50-60% at 100-130°C, but with low N 2 selectivity. The N 2 selectivity on Pd/K 2 O-6TiO 2 was considerably high, reaching 80% at maximum, with only 11% conversion of the admixed hydrogen reductant. In situ DRIFT spectroscopy revealed surface-fixed nitrates and Pd-bound NO, but no NH x ad-species. It is concluded, that the beneficial effect of the K 2 O-6TiO 2 support is due mainly to a stabilization of high Pd dispersion with enhanced concentration of Pd 0 -NO intermediates, and due to support alkalinity, that enhances nitrate fixation.

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Section: Mechanism Considerationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

NO selective reduction by hydrogen on potassium titanate supported palladium catalyst

Zhang

Guan

et al. 2008

Catalysis Communications

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“…In the past decades, various hydrocarbons [8][9][10][11][12][13][14] have been studied as reductant for the purpose of removing NO x in excess oxygen, which was expressed as HC-SCR, whereas their poor activity and selectivity under low temperature towards the aimed reaction make this technology hardly developed. Recently, hydrogen [15][16][17][18][19][20][21][22] has been proved to be effective reductant for NO x reduction in excess oxygen because of its high activity towards NO reduction and zero emissions of greenhouse gases in the reaction. Recent research works [5][6][7] have revealed that this reaction under industrial conditions is possible and the SCR of NO by H 2 (H 2 -SCR) might be a breakthrough NO x control technology in favor of the NH 3 -SCR in application.…”

Section: Introductionmentioning

confidence: 99%

“…Since H 2 -SCR could effectively eliminate NO at much lower temperature compared with HC-SCR, it has attracted much attention in recent years [15][16][17][18][19][20][21][22], in particular its reaction mechanism. Two main kinds of reaction mechanism for the reaction have been proposed in the literature.…”

Section: Introductionmentioning

confidence: 99%

An investigation of the surface intermediates of H2-SCR of NO over Pt/H-FER

Yang

Wang

Chu

et al. 2011

Applied Catalysis B: Environmental

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“…Significant attention has been given to the development of selective catalytic reduction (SCR) of NO x using H 2 [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], CO [19][20][21], or a mixture of H 2 /CO [22][23][24][25][26][27][28][29][30][31][32][33] as reductant. Catalysts using H 2 and/or CO have the advantage of lowtemperature DeNO x activity, and the reductants could be produced using an on-board fuel reformer, thus eliminating the need of carrying any additional reductant.…”

Section: Introductionmentioning

confidence: 99%

Influence of Supports on Pd Catalysts for the Selective Catalytic Reduction of NOx with H2 and CO

Caravaggio

Nossova

Burich

2015

Emiss. Control Sci. Technol.

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A major concern of current commercial catalysts for the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) (DeNO x ) is the lack of sufficient catalytic activity at low temperatures (below 200°C) that typically occur during cold start and urban driving conditions. To address this issue, a study was undertaken to develop an (H 2 + CO)-SCR Pd-based catalyst to obtain high DeNO x activity in this low-temperature range. A series of catalysts with Pd loaded on supports containing various amounts of γ-alumina (γ-Al 2 O 3 ) (0-65 wt%), CBV-2314 (15-100 wt%), and TiO 2 (0-20 wt%) were tested for DeNO x activity and aging in a catalyst testing unit (CTU). The results showed that each component in the support played a role in the NO x conversion, depending on the temperature. Catalysts with Pd supported on {[γ-Al 2 O 3 (60 wt%)+CBV-2314 (20 wt%)]-TiO 2 (20 wt%)} achieved the best overall DeNO x activity. Catalysts with various Pd loadings (0.05 wt% to 0.5 wt%) were prepared with a {[γ-Al 2 O 3 (60 wt%)+CBV-2314 (20 wt%)]−TiO 2 (20 wt%)} support. The catalysts loaded with 0.05 wt% and 0.2 wt% Pd demonstrated the best overall DeNO x activity (up to 90 % NO x conversion starting at 150°C). These catalysts were subjected to an accelerated aging regime. Based on the aging studies, the 0.2 wt% Pd/{[γ-Al 2 O 3 (60 wt%)+CBV-2314 (20 wt%)]− TiO 2 (20 wt%)} composition was the most active and stable catalyst.

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Low temperature catalytic NOx–H2 reactions over Pt/TiO2-ZrO2 in an excess oxygen

Cited by 134 publications

References 22 publications

NO selective reduction by hydrogen on potassium titanate supported palladium catalyst

NO selective reduction by hydrogen on potassium titanate supported palladium catalyst

An investigation of the surface intermediates of H2-SCR of NO over Pt/H-FER

Influence of Supports on Pd Catalysts for the Selective Catalytic Reduction of NOx with H2 and CO

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