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Title: Catalytic ammonia decomposition over industrial-waste-supported Ru catalysts

Abstract

Industrial solid wastes (fly ash and red mud, a by-product of the aluminium industry) have been employed as supports for preparation of Ru-based catalysts. Physical and chemical treatments on red mud were conducted and these modified supports were also used for preparation of Ru-based catalysts. Those Ru catalysts were characterized by various techniques such as N2 adsorption, H{sub 2} adsorption, XRD, XPS, and temperature-programmed reduction (TPR), and were then tested for catalytic ammonia decomposition to hydrogen. It was found that red-mud-supported Ru catalyst exhibits higher ammonia conversion and hydrogen production than fly-ash-supported catalyst. Heat and chemical treatments of the red mud greatly improve the catalytic activity. Moreover, a combination of acid and heat treatments produces the highest catalytic conversion of ammonia. 35 refs., 4 figs., 4 tabs.

Authors:
; ; ; ; ;  [1]
  1. University of Queensland, St Lucia, Qld. (Australia). ARC Functional Nanomaterials
Publication Date:
OSTI Identifier:
20905843
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 41; Journal Issue: 10; Other Information: johnz@cheque.uq.edu.au
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; RUTHENIUM; CATALYSTS; AMMONIA; DECOMPOSITION; FLY ASH; CATALYST SUPPORTS; HYDROGEN; COAL; WASTE PRODUCT UTILIZATION; ALUMINIUM OXIDES; BY-PRODUCTS; CATALYTIC EFFECTS; ADSORPTION; CALCINATION; HEAT TREATMENTS; PH VALUE; SURFACE PROPERTIES; X-RAY DIFFRACTION; SILICA; HYDROGEN PRODUCTION

Citation Formats

Pei Fang Ng, Li Li, Shaobin Wang, Zhonghua Zhu, Gaoqing Lu, and Zifeng Yan. Catalytic ammonia decomposition over industrial-waste-supported Ru catalysts. United States: N. p., 2007. Web.
Pei Fang Ng, Li Li, Shaobin Wang, Zhonghua Zhu, Gaoqing Lu, & Zifeng Yan. Catalytic ammonia decomposition over industrial-waste-supported Ru catalysts. United States.
Pei Fang Ng, Li Li, Shaobin Wang, Zhonghua Zhu, Gaoqing Lu, and Zifeng Yan. Tue . "Catalytic ammonia decomposition over industrial-waste-supported Ru catalysts". United States. doi:.
@article{osti_20905843,
title = {Catalytic ammonia decomposition over industrial-waste-supported Ru catalysts},
author = {Pei Fang Ng and Li Li and Shaobin Wang and Zhonghua Zhu and Gaoqing Lu and Zifeng Yan},
abstractNote = {Industrial solid wastes (fly ash and red mud, a by-product of the aluminium industry) have been employed as supports for preparation of Ru-based catalysts. Physical and chemical treatments on red mud were conducted and these modified supports were also used for preparation of Ru-based catalysts. Those Ru catalysts were characterized by various techniques such as N2 adsorption, H{sub 2} adsorption, XRD, XPS, and temperature-programmed reduction (TPR), and were then tested for catalytic ammonia decomposition to hydrogen. It was found that red-mud-supported Ru catalyst exhibits higher ammonia conversion and hydrogen production than fly-ash-supported catalyst. Heat and chemical treatments of the red mud greatly improve the catalytic activity. Moreover, a combination of acid and heat treatments produces the highest catalytic conversion of ammonia. 35 refs., 4 figs., 4 tabs.},
doi = {},
journal = {Environmental Science and Technology},
number = 10,
volume = 41,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • The catalytic performance in ethylene hydroformylation over SiO[sub 2], MgO, and carbon-supported Ru, Ru-Co, Ru-Mn, Ru-Cr, and Co carbonyl cluster-derived catalysts has been investigated, and it was found that the catalysts derived from Ru monometallic and Ru-Co bimetallic carbonyl clusters are active in ethylene hydroformylation. The presence of Co atoms in Ru-Co carbonyl clusters led to a remarkable increase in the rate of product formation, especially for oxygenates. The Ru-Mn bimetallic carbonyl cluster-derived catalyst showed similar conversion, but it exhibited poor activity and selectivity for oxygenates as compared with catalysts derived from Ru[sub 6]C(CO)[sub 17]. In contrast to the Ru[submore » 6]C(CO)[sub 17] carbonyl cluster-derived catalyst, the Ru-Cr bimetallic carbonyl cluster-derived catalyst exhibited very low activity and selectivity for ethane and oxygenates, indicating that the Cr sites in Ru-Cr bimetallic carbonyl cluster-derived catalyst have a poisoning effect on ethylene hydroformylation. The nature of support has been shown to have a large influence on the catalytic activity and selectivity of the resulting catalyst. The effect of Co promotion in Ru-Co carbonyl clusters on silica and carbon was much stronger than that on MgO. The nature of these Ru-Co/SiO[sub 2] catalysts has been investigated by infrared and X-ray photoelectron spectroscopes. 70 refs., 14 figs., 6 tabs.« less
  • This study examines the ammonia dependence of the synthesis rate over supported (but unpromoted) ruthenium using data collected with a flow reactor coupled with effluent ammonia determination. Silica gel and ..gamma..-alumina powder were impregnated to Ca. 1.0 to 1.3 wt % ruthenium loading by incipient wetness using an aqueous solution of RuCl/sub 3/ . 3 H/sub 2/O. Following this impregnation, the samples were dried overnight in air at 380 K, and then a portion, 1.5 g in the case of the silica-supported sample and 2.2 g in the case of the alumina-supported sample, was loaded into a flow reactor formore » hydrogen reduction (at 700K for ca. 50h) and subsequent ammonia synthesis studies at atmospheric pressure (0.1 MPa). This study has yielded ammonia synthesis turnover frequencies and apparent activation energies at constant flow rate that are in good agreement with the results of Ozaki et al. This study has also shown that the rate of ammonia synthesis does indeed exhibit an ammonia dependence in the same range of ammonia pressures studied by Ozaki et al. Apparent activation energies calculated at constant ammonia pressure are greater than those determined at constant flow rate. 6 figures, 1 table. (DP)« less
  • The reaction of 3:1 hydrogen-nitrogen over (unpromoted) ruthenium on silica gel or ..gamma..-alumina was studied in a flow reactor at 1.2-3.8 cc/sec volumetric flow rates and 691/sup 0/-574/sup 0/K, under which conditions the equilibrium ammonia partial pressure varied from 318-1910 Pa. The plot of partial ammonia pressure vs. the logarithm of the reciprocal volumetric flow rate had slopes of 0.64 and 0.50 for the silica- and alumina-supported catalysts, respectively. The log-log plots of turnover number vs. partial ammonia pressure had slopes of -0.56 and -1.0 for the silica- and alumina-supported catalysts, respectively. The over-all rate of ammonia production is thusmore » inversely related to the ammonia partial pressure, which is contrary to literature data obtained in a recirculation system. Implications on the rate equation are discussed.« less
  • The effect of the reducing agent on the performance of a ruthenium nanoparticle catalyst was investigated during aqueous-phase Fischer–Tropsch synthesis using a 1 L stirred tank reactor in the batch mode of operation. For the purpose of comparison, the activity and selectivity of NaY zeolite supported Ru catalyst were also studied. NaBH 4 and hydrogen were used as reducing agents in our study, and hydrogen reduced catalysts exhibited higher activities than the NaBH 4 reduced catalysts, because of higher extent of reduction and a relatively lower tendency toward agglomeration of Ru particles. The Ru nanoparticle catalyst displayed higher activities thanmore » the NaY zeolite supported Ru catalyst for both reducing agents. NaBH 4 reduced catalysts are less active and the carbon dioxide selectivity is higher than the hydrogen reduced catalysts. The activity of the supported Ru catalyst (Ru/NaY) was 75 % of that of the Ru nanoparticle catalyst, and has the benefit of easy wax/catalyst slurry separation by filtration. Finally, the hydrogen reduced supported Ru catalyst exhibited superior selectivity towards hydrocarbons (higher C 5+ selectivity and lower selectivity to methane) than all other catalysts tested.« less
  • The reason proposed for the modification of the catalytic properties of supported platinum in n-hexane conversion under the influence of additives is the change in the adsorption of reagents on platinum, due to the interaction of the latter with surface low-valence ions of the second element. In the sequence of additives Sn ..-->.. Pb ..-->.. W ..-->.. Mo ..-->.. Re, we can expect an increase in the proportion of strongly bound forms of n-hexane adsorbed on platinum (in this sequence the contribution of n-hexane hydrogenolysis increases). At the same time, the role of the reactions that must form more labilemore » adsorbed forms (isomerization, dehydrogenation to olefin, C/sub 5/ cyclization) must decrease.« less