Oxidative coupling of methane over NbO (p-type) and Nb2O5 (n-type) semiconductor materials

Erarslanoglu, Y
Onal, I
Doğu, Timur
Senkan, S
Oxidative coupling of methane to higher hydrocarbons was investigated using two types of semiconductor catalysts, NbO (p-type) and Nb2O5 (n-type) at 1 atm pressure. The ratio of methane partial pressure to oxygen partial pressure was changed from 2 to 112 and the temperature was kept at 1023 K in the experiments conducted in a cofeed mode. The results indicated a strong correlation between C-2+ selectivity performance and the electronic properties of the catalyst in terms of p- vs. n-type conductivity. The p-type semiconductor catalyst, NbO, had a larger selectivity (e.g. 95.92%) over the n-type Nb2O5 catalyst (23.08%) both at the same methane conversion of 0.64%. Catalyst characterization via X-ray diffraction, TGA and reaction studies indicated that NbO was transformed to Nb2O5 during the course of the reaction which limits catalyst life.


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Activation of methane with a halogen followed by the metathesis of methyl halide is a novel route from methane to higher hydrocarbons or oxygenates. Thermodynamic analysis revealed that bromine is the most suitable halogen for this goal. Analysis of the published data on the reaction kinetics in a CSTR enabled us to judge on the effects of temperature, reactor residence time and the feed concentrations of bromine and methane to the conversion of methane and the selectivity towards mono or dibromomethane. Th...
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Karakaş, Gürkan (Springer Science and Business Media LLC, 2013-12-01)
The photocatalytic oxidation of carbon monoxide over TiO2-SiO2 and Pd/TiO2-SiO2 catalysts was studied. The catalyst samples were synthesized by using sol-gel technique coupled with hydrothermal treatment and all samples were hydrothermally treated before calcination in air. The catalyst samples were characterized by XRD, BET and DRIFTS techniques. The photocatalytic activity of the samples was determined by using circulated batch photoreactor coupled with in line gas transmission FTIR cell charged with 2,00...
Coke Minimization in Dry Reforming of Methane by Ni Based Mesoporous Alumina Catalysts Synthesized Following Different Routes: Effects of W and Mg
ARBAĞ, HÜSEYİN; YAŞYERLİ, SENA; YAŞYERLİ, NAİL; Doğu, Timur; DOĞU, GÜLŞEN (Springer Science and Business Media LLC, 2013-12-01)
Ni based mesoporous alumina (MA) catalysts were synthesized by sol-gel (SGA) and hydrothermal (MA) methods, following impregnation and one-pot synthesis routes and catalytic performances of these materials were tested in dry reforming of methane. Results proved the importance of synthesis procedure of the MA supports on the activity and coke resistance of the synthesized materials, containing 16 % Ni. Among these catalysts, MA prepared by the sol-gel technique (Ni@SGA) showed the highest activity in dry ref...
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Among the hydrogen storage materials, ammonia-borane and sodium borohydride appear to be promising candidates as they can release hydrogen on hydrolysis in aqueous solution under mild conditions. Here, we report the development of a cost-effective and highly active nickel(0) nanoparticles catalyst for the hydrolysis of ammonia-borane and sodium borohydride. Nickel(0) nanoparticles confined in zeolite framework were prepared by using our previously established procedure and characterized by ICP-OES, XRD, TEM...
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Üner, Deniz (Elsevier BV, 2016-09-01)
The role of spilled over hydrogen in ammonia synthesis reaction was monitored over Ru/SiO2, Ru/SBA15 and Ru/CNF using an in-situ DRIFTS cell reactor. Strongly bound hydrogen trapped on the metal and spilled over hydrogen trapped on the support due to a diffusion barrier remained on the surface after the overnight purge followed by hydrogen exposure over a reduced catalyst. When N-2 flow was introduced at room temperature, IR characteristic signals of NH3 were observed, indicating the formation of ammonia fr...
Citation Formats
Y. Erarslanoglu, I. Onal, T. Doğu, and S. Senkan, “Oxidative coupling of methane over NbO (p-type) and Nb2O5 (n-type) semiconductor materials,” CATALYSIS LETTERS, pp. 215–218, 1996, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/62943.