A comparative study of catalysts for the preferential CO oxidation in excess hydrogen

Ko, E.I.; Park, Eun Duck; Seo, Kyung Won; Lee, Hyun Chul; Lee, Doohwan; Kim, Soonho

doi:10.1016/j.cattod.2006.05.072

Cited by 92 publications

(32 citation statements)

References 48 publications

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“…Larger Au particles were observed by Hutchings et al for Au/CuO catalysts prepared by CP, where the mean Au particle size was 20-30 nm, and there were many particles as large as 50 nm [25]. In contrast, Ko et al obtained a Au/CuO sample prepared by DP from Cu(OH) 2 with an average gold particle size of 3.8 ± 0.5 nm [60]. Au/NiO samples were also analysed by HRTEM.…”

Section: Hrtem/haadf/edxsmentioning

confidence: 85%

Gold supported on metal oxides for carbon monoxide oxidation

Carabineiro

Bogdanchikova²,

Avalos-Borja³

et al. 2010

Nano Res.

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Au has been loaded (1% wt.) on different commercial oxide supports (CuO, La 2 O 3 , Y 2 O 3 , NiO) by three different methods: double impregnation (DIM), liquid-phase reductive deposition (LPRD), and ultrasonication (US). Samples were characterised by N 2 adsorption at -196 °C , high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectrometry, high-angle annular dark-field imaging (Z-contrast), X-ray diffraction, and temperature programmed reduction. CO oxidation was used as a test reaction to compare the catalytic activities. The best results were obtained with Au loaded by DIM on the NiO support, with an activity of 7.2 × 10 -4 mol CO· g Au -1 · s -1 at room temperature. This is most likely related to the Au nanoparticle size being the smallest in this catalyst (average 4.8 nm), since it is well known that gold particle size determines the catalytic activity. Other samples, having larger Au particle sizes (in the 2-12 nm range, with average sizes ranging from 4.8 to 6.8 nm), showed lower activities. Nevertheless, all samples prepared by DIM had activities (from 1.1 × 10 -4 to 7.2 × 10 -4 mol CO· g Au -1 · s -1 , at room temperature) above those reported in the literature for gold on similar oxide supports. Therefore, this method gives better results than the most usual methods of deposition-precipitation or co-precipitation.

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Section: Hrtem/haadf/edxsmentioning

confidence: 85%

Gold supported on metal oxides for carbon monoxide oxidation

Carabineiro

Bogdanchikova²,

Avalos-Borja³

et al. 2010

Nano Res.

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“…For Rh and Ru, complete conversion was obtained below 100 ı C, whereas for Pt, it occurred at 200 ı C. The complete conversion at low temperature for Ru and Rh was associated with methanation which is undesirable. Ko et al [24] used very low amount of Pt (0.05 %) for a feed stream containing 1 % CO, 1 % O 2 , 80 % H 2 , 2 % H 2 O, and balance He and obtained only 70 % conversion along with 30 % selectivity at a temperature of 200 ı C. Ouyang et al [50] used microkinetic modeling to show that at low CO conversions, the metal sites are mostly covered by adsorbed CO leading to high selectivity, but at high conversions (i.e., when very little CO was present in the gas phase), the metal sites are occupied by adsorbed oxygen and hydrogen resulting in loss of hydrogen by oxidation. Moreover, with an increase in temperature, the coverage of active sites by CO decreases, and more hydrogen is adsorbed which again results in lower selectivity at high temperature.…”

Section: Preferential Oxidation Of Carbon Monoxidementioning

confidence: 97%

Microstructured Reactors for Hydrogen Production from Ethanol

Peela

Kunzru

2015

Springer Tracts in Mechanical Engineering

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The continuously increasing demand for clean and renewable energy warrants the development of renewable, nonpolluting energy resources. Hydrogen is emerging as a natural choice as a more secure and cleaner energy carrier. Fuel cells can be used to produce clean energy from hydrogen, particularly for portable applications. Hydrogen can be produced from a variety of fossil fuel sources, but to decrease the dependence on fossil fuels, hydrogen has to be produced from a renewable source. Hydrogen production from steam reforming of ethanol (a renewable fuel) has emerged as a promising alternative in recent years. For conducting this reaction on board a vehicle, a compact reactor system is required. A microchannel reactor is more efficient and attractive for this purpose, because of the high surface to volume ratio, resulting in high heat and mass transfer rates.The reactions involved in producing CO-free hydrogen from ethanol include steam reforming of ethanol, water-gas shift reaction, and preferential oxidation of carbon monoxide. This chapter discusses the steps involved in the development of a microfuel processor for producing hydrogen from ethanol that include fabrication of the microchannels on the metal substrate, coating of the catalyst and support on the microchannels, assembly of the microchannel reactor, optimization of the catalysts for the three reactions, and, finally, heat integration of the different processes to maximize the efficiency of the fuel processor.

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“…The articles reviewed here show quite different results for stability. In most of the cases stability tests were not performed [7,8,17,[20][21][22]25,27,29,[33][34][35][36][37][38][39]. In the remaining works, stability tests were conducted for time durations ranging from 12 to 200 h, at temperatures in the 80.175 • C range.…”

Section: Catalyst Stabilitymentioning

confidence: 99%

“…Consequently there is only a limited number of articles that provide such a comparison [6,7]. In the majority of works the catalytic activities of a number of different catalysts prepared by the same authors and tested under identical conditions are compared [8][9][10]. The main reason for the lack of comparative works might be the difficulty in finding a common basis of comparison regarding the activity, selectivity and stability of the copper-based catalysts.…”

mentioning

confidence: 97%