Grabchenko, M. V.

Liotta, L. F.

Pantaleo, G.

Puleo, F.

Vodyankina, Olga V.

English

Tomsk State University Repository

 CATALYSIS: from Science to Industry 2018 Section 2: Oral presentations  50  Ni/La2O3 catalysts for dry reforming of methane: effect of synthesis conditions on the structural properties and catalytic performances F. Puleo1, M. V. Grabchenko2, G. Pantaleo1, O. Vodyankina2, L.F. Liotta1 1Institute for the Study of Nanostructured Materials, Palermo, Italy 2Tomsk State University, Tomsk, Russia marygra@mail.ru  Dry reforming of methane (DRM) is highly endothermic (∆H°25°C = 247 kJ/mol) and normally requires temperatures above 700°C to attain good conversion levels [1]. Nickel is the most frequently reported metal in DRM because of its good catalytic activity and its cost-effectiveness as compared with Rh, Ru, Pt, and Pd-based catalysts [2]. However, the main drawback of Ni based catalysts is represented by the production of significant amount of carbon and by the sintering at the high temperatures of the reaction. Carbon deposits are formed when the rate of methane dissociation is faster than the oxidation of carbon by the surface oxygen species arising from CO2 dissociation on the metal component or from carbonates formed at the metal support interface [3, 4]. Until now, many studies have demonstrated that metal oxides such as CeO2, MgO, ZrO2 have positive effects on catalytic activity, stability and carbon suppression of nickel catalysts for DRM [5, 6]. In the present work the physical chemical properties, the related catalytic activity and the long-run stability of Ni-La2O3 catalysts have been evaluated in DRM reaction. The aim was to investigate the effect of ammonia addition during the synthesis of La2O3 oxide carried out by sol-gel method in presence of citric acid. Ni(10%wt) was deposited by wetness impregnation over two La2O3 oxides prepared with and without adding NH3 solution during the synthesis, the corresponding catalysts were labelled as Ni-La CA and Ni-La CA-NH3, respectively. The so far prepared catalysts were characterized by BET, XRD and TPR techniques.  The XRD patterns of the supports calcined at 800 °C showed that ammonia addition favors the formation of La2O3 phase with respect to La(OH)3. La2O3 was the only lanthanum phase detected in the XRD pattern of Ni-La CA-NH3, after calcination at 600 °C and reduction treatment at 700 °C, moreover, weak features attributed to dispersed metallic Ni particles were found.  While in the case of Ni-La CA, both phases, La2O3 and La(OH)3 were present along with well visible peaks of metallic Ni suggesting the presence of big clusters. DRM gradient catalytic test performed between 400°C to 800°C revealed higher catalytic activity of Ni-La CA, nevertheless long run test showed a better stability of Ni-La CA-NH3 catalyst. The spent catalysts were characterized by XRD, TGA, Raman and TEM analyses. In both samples La2O2CO3 phase was formed together with C graphite peak of higher intensity in the case of Ni-La CA in agreement with greater weight loss revealed by TGA and stronger deactivation during long run with respect to Ni-La CA-NH3. The effect of the nature of the catalyst on the amount of carbon coke formed during DRM was also confirmed by Raman and TEM results.  This work was supported by the Russian Presidential Scholarship assigned to M.V. Grabchenko who spent 6 months (2nd October 2017-2nd April 2018) at ISMN-CNR in Palermo, Italy.  References 1. Lavoie, J.M. Front Chem. 2014, 11, 2-81. 2. Pakhare, D.; Spivey, J. Chem. Soc. Rev., 2014, 43, 7813-7837. 3. Jia, Z.; Kou, K.; Qin, M. et al. Catalysts 2017, 7, 256-276.  4. Horváth, A.; Guczi, L.; Kocsonya, A. et al. Appl. Catal. A: General  2013, 468 250– 259. 5. Mesrar, F.; Kacimi, M.; Liotta, L.F. et al. Int. J. Hydrogen Energy 2017, 42, 19458-19466. 6. Fan, M.S.; Abdullah, A.Z.; Bhatia, S.; ChemSusChem 2011, 4, 1643-1653. 

Ni/La2O3 catalysts for dry reforming of methane: effect of synthesis conditions on the structural properties and catalytic performances

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Ni/La2O3 catalysts for dry reforming of methane: effect of synthesis conditions on the structural properties and catalytic performances

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