Reaction of CO2CH4 as a high-level heat transport system

Tokunaga, Osamu; Osada, Yo; Ogasawara, Sadao

doi:10.1016/0016-2361(89)90063-x

Cited by 34 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…proton exchange membrane fuel cells, anion exchange membrane fuel cells and solid oxide fuel cell, etc . Though hydrogen can be produced by several methods, for example, water electrolysis, partial oxidation, and gasification of heavy oils, etc., but the most developed and economically cheap catalytic industrial process is the steam methane reforming(SMR) . Nickel based catalysts are widely used for its good initial reactivity, relatively lower price than the noble metals, and are easily available .…”

Section: Introductionmentioning

confidence: 99%

Methane Dissociation on Bimetallic AuNi₃, Au₂Ni₂ and Au₃Ni Clusters‐A DFT Study

Roy

Chattopadhyay

2018

ChemistrySelect

View full text Add to dashboard Cite

The effect of gold atom for the dissociation of methane on tetrahedral bimetallic Au x Ni y (x + y = 4; x,y = 1-3) clusters are introduced using density functional theory method. The binding energy and HOMO-LUMO gap fluctuate with odd-even number of gold atoms. The clusters, AuNi 3 and Au 3 Ni, containing odd number of doped gold atoms, which causes open shell configuration, are exceptionally stable and highly resistance to carbon deposition, whereas closed shell Au 2 Ni 2 cluster is less stable. As the number of doped Au atom increases in the clusters, adsorption or binding energy of methane increases. The dissociation of methane is a four elementary steps process, and first step of dissociation, CH 4 ! CH 3 , is not the rate determining step, and thermodynamically favorable at room temperature and pressure for the clusters due to adsorption. Whereas, the dissociation of CH!C, coke formation step 4, is the rate determining step due to highest energy barrier for all the clusters. The calculated activation energies for the rate determining step are 0.92 eV, 0.41 eV and 1.64 eV for AuNi 3 , Au 2 Ni 2 and Au 3 Ni clusters, respectively. In addition, the dissociation temperature for all the intermediates, e. g., CH 3 , CH 2 and CH are 450 K(CH 3 and CH 2 ) and 650 K(CH) on AuNi 3 cluster; 450 K(CH 3 ) and 550 K(CH 2 and CH) on Au 2 Ni 2 cluster; and 650 K(CH 3 ), 750 K(CH 2 ) and 950 K(CH) on Au 3 Ni cluster. Thus, the coke resistivity decreases as Au 3 Ni > AuNi 3 > Au 2 Ni 2 and corresponding coke resistance temperatures are 950 K, 650 K and 550 K, respectively. The charge tranfer to the clusters during adsorption is negative, and is positive in the dissociation steps. Thus, the number of doped gold atom not only influences the stability of bimetallic AuÀNi clusters, but also their reactivity towards methane, which can provide some new insight for the design of coke resistant catalysts for methane reforming.[a] Prof.

show abstract

Section: Introductionmentioning

confidence: 99%

Methane Dissociation on Bimetallic AuNi₃, Au₂Ni₂ and Au₃Ni Clusters‐A DFT Study

Roy

Chattopadhyay

2018

ChemistrySelect

View full text Add to dashboard Cite

show abstract

“…The process of carbon dioxide reforming of methane (CH 4 /CO 2 ), which converts two of the cheapest carbon-containing materials into useful chemical products, i.e., synthesis gas (H 2 /CO), has received considerable attention in recent years. Compared to steam reforming of methane (CH 4 /H 2 O) to synthesis gas, this process offers several advantages: (1) production of synthesis gas with a lower hydrogen-to-carbon monoxide ratio, which is suitable for use in Fischer−Tropsch synthesis to higher hydrocarbons; (b) utilization of CO 2 , which is considered to be an important greenhouse gas; (c) better use in chemical energy transmission systems, i.e., solar or nuclear energy or renewable energies. , …”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Carbon Dioxide Reforming of Methane to Synthesis Gas over Ni/La₂O₃and Conventional Nickel-Based Catalysts

et al. 1996

View full text Add to dashboard Cite

Carbon dioxide reforming of methane to synthesis gas was studied by employing a Ni/La2O3 catalyst as well as conventional nickel-based catalysts, i.e., Ni/γ-Al2O3, Ni/CaO/γ-Al2O3, and Ni/CaO. It is observed that, in contrast to conventional nickel-based catalysts, which exhibit continuous deactivation with time on stream, the rate of reaction over the Ni/La2O3 catalyst increases during the initial 2−5 h and then tends to be essentially invariable with time on stream. X-ray photoelectron spectroscopy (XPS) studies show that the surface carbon on spent Ni/Al2O3 catalyst is dominated by −C−C− species that eventually block the entire Ni surface, leading to total loss of activity. The surface carbon on the working Ni/La2O3 catalyst is found to consist of −C−C− species and a large amount of oxidized carbon. Both XPS and secondary ion mass spectrometry results reveal that a large fraction of surface Ni on the working Ni/La2O3 catalyst is not shielded by carbon deposition. FTIR studies reveal that the enhancement of the rate of reaction over the Ni/La2O3 catalyst during the initial 2−5 h of reaction correlates well with increasing concentrations of La2O2CO3 and formate species on the support, suggesting that these species may participate in the surface chemistry to produce synthesis gas. It is proposed that the interaction between nickel and lanthanum species creates a new type of synergetic sites at the Ni−La2O3 interfacial area, which offer active and stable performance of carbon dioxide reforming of methane to synthesis gas over the stated catalyst.

show abstract

“…The subsequent {mCO + nH 2 } reactions are quite favorable thermodynamically, which strongly shift towards the product side while competing with one another. 5 The reverse WGS reaction, which is slightly endothermic, might contribute to the {mCO + nH 2 } reactions to some extent, though there would eventually remain nothing but a small amount of CO.…”

mentioning

confidence: 99%