Effect of Additives on Mn/SiO2 Based Catalysts on Oxidative Coupling of Methane

Authors

  • Marzieh Hamidzadeh Catalyst Department, National Petrochemical Company, Research & Technology (NPC-RT), Tehran, I.R. IRAN
  • Mohammad Reza Ehsani Faculty of Chemical Engineering, Isfahan University of Technology, P.O. Box 84156-83111 Isfahan, I.R. IRAN
  • Somayeh Mahmoodi Faculty of Chemical Engineering, Isfahan University of Technology, P.O. Box 84156-83111 Isfahan, I.R. IRAN
Abstract:

The Oxidative Coupling of Methane (OCM) over M-Na-Mn/SiO2 catalysts (M=W, Cr, Nb and V) was investigated using a continuous-flow quartz reactor at 775°C, 1 atm and 100 cm3min-1 gas flow rates, and correlated with the observed structure and redox properties.The interaction effects of the metal-metal and metal-support on the methane conversion and C2+ yield were investigated using X-Ray Diffraction (XRD), laser Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), and Temperature Programmed Reduction with H2 (TPR). The results revealed that the improvement of C2+ selectivity (or C2+ yield) follows the order W>Cr>Nb>V, while the catalytic conversion did not change significantly. XRD data indicated that Mn is well dispersed on the SiO2 support and also show that Mn2O3 and α-cristobalite were the predominant species in the surface catalysts. TPR data show that most of the Mn is present as Mn3+ and Mn2+. FT-IR analyses combined with the Raman results show that terminal M=O and bridging M–O–M species and the metal–metal and metal–support interactions, which take place due to the presence of sodium ion, depend on the transition metal that affect the catalyst performance. Results reveal that the interaction between metal oxide and sodium is required for high selectivity and control redox mechanism in transition metal oxide in OCM reaction.  

Upgrade to premium to download articles

Sign up to access the full text

Already have an account?login

similar resources

effect of additives on mn/sio2 based catalysts on oxidative coupling of methane

the oxidative coupling of methane (ocm) over m-na-mn/sio2 catalysts (m=w, cr, nb and v) was investigated using a continuous-flow quartz reactor at 775°c, 1 atm and 100 cm3min-1 gas flow rates, and correlated with the observed structure and redox properties.the interaction effects of the metal-metal and metal-support on the methane conversion and c2+ yield were investigated using x-ray diffracti...

full text

Effect of Additives on Lithium Doped Magnesium Oxide Catalysts Used in the Oxidative Coupling of Methane

It has been found that it is possible to improve the activity and stability for the oxidative coupling of methane of a Li/MgO catalyst by the addition of small amounts of the oxides of various transition and rare earth metals. A number of these additives, e.g. SnOZ, TiOz, Dy,O, and Tb407, caused little or no difference in the selectivity to C, products achieved with the resultant catalyst while...

full text

the effect of genre-based teaching on reading comprehension of literary texts

تحقیق حاضر به بررسی کاربرد روش ژانر-محور را در محیط آموزش زبان عمومی می پردازد.روش ژانر-محور به زبان آموزان کمک میکند که در زمینه خوانش پیشرفت کنند. بعضی از محققین معتقد اند که روش تدریس ژانر-محور به تدریج به زبان آموزان کمک می کند تا در درک ژانر های مختلف مهارت یابند (هایلند 2004).همچنین امروزه توجه روز افزونی به اهمیت استفاده از ادبیات در برنامه آموزشی زبان انگلیسی (esl/efl ) شده است. زمانی ک...

15 صفحه اول

effect of oral presentation on development of l2 learners grammar

this experimental study has been conducted to test the effect of oral presentation on the development of l2 learners grammar. but this oral presentation is not merely a deductive instruction of grammatical points, in this presentation two hypotheses of krashen (input and low filter hypotheses), stevicks viewpoints on grammar explanation and correction and widdowsons opinion on limited use of l1...

15 صفحه اول

the effect of lexically based language teaching (lblt) on vocabulary learning among iranian pre-university students

هدف پژوهش حاضر بررسی تاثیر روش تدریس واژگانی (واژه-محور) بر یادگیری لغات در بین دانش آموزان دوره پیش دانشگاهی است. بدین منظور دو گروه از دانش آموزان دوره پیش دانشگاهی (شصت نفر) که در سال تحصیلی 1389 در شهرستان نور آباد استان لرستان مشغول به تحصیل بودند انتخاب شده و به صورت قراردادی گروه آزمایش و گواه در نظر گرفته شدند. در ابتدا به منظور اطمینان یافتن از میزان همگن بودن دو گروه از دانش واژگان، آ...

15 صفحه اول

My Resources

Save resource for easier access later

Save to my library Already added to my library

{@ msg_add @}


Journal title

volume 30  issue 1

pages  29- 36

publication date 2011-03-01

By following a journal you will be notified via email when a new issue of this journal is published.

Hosted on Doprax cloud platform doprax.com

copyright © 2015-2023