435279 Selective CO Methanation over Ceria-Supported Ni, Co, Fe Catalysts

Wednesday, November 11, 2015
Exhibit Hall 1 (Salt Palace Convention Center)
Dmitriy Potemkin1,2, Pavel Snytnikov1,2,3, Margarita Konishcheva1,2 and Vladimir Sobyanin1,2, (1)Boreskov Institute of Catalysis, Novosibirsk, Russia, (2)Novosibirsk State University, Novosibirsk, Russia, (3)UNICAT Ltd., Novosibirsk, Russia

1. Introduction

The selective CO methanation in hydrogen-rich gas mixtures in the presence of CO2 is a promising way for deep CO removal designed for low-temperature proton-exchanged membrane fuel cell feeding applications, as well as a challenging fundamental problem of substrate-selective hydrogenation. Besides the target CO methanation reaction (1), undesirable CO2 methanation (2) and reverse water-gas shift (3) reactions may occur, causing considerable hydrogen losses and increasing CO outlet concentration:

CO+3H2 = CH4 + H2O;         ΔHo= -206 kJ/mol                 (1)

CO2+4H2 = CH4 + 2H2O;      ΔHo= -165 kJ/mol                 (2)

CO2 + H2 = CO + H2O;         ΔHo= 41 kJ/mol                     (3)

In spite of extensive research efforts Ru- and Ni-based systems remain the most active catalysts for CO and CO2methanation [1]. At the same time, metals such as Co and Fe are known to be active in carbon oxides hydrogenation reactions, including Fischer-Tropsch synthesis and RWGS, but the properties of Fe and Co-based systems in the selective CO methanation are not studied.

This work reports the results of comparative study of Ni-, Co- and Fe/CeO2catalysts, prepared from nitrate and chloride precursors, in the selective CO methanation.

2. Experimental

Catalysts with metal loading of 10 wt.% were prepared by incipient wetness impregnation of CeO2 by the water solutions of metal's nitrate (Ni/CeO2, Co/CeO2, Fe/CeO2) and chloride (Ni(Cl)/CeO2, Co(Cl)/CeO2, Fe(Cl)/CeO2) salts. They were characterized by BET, XRD, TEM, EDX, XPS, FTIR and CO chemisorption techniques. Selective CO methanation was studied in a flow reactor at atmospheric pressure in the temperature interval 180 − 360 °C, at WHSV = 29 000 cm3g-1h-1 and feed gas composition (vol.%): 1.0 CO, 20 CO2, 10 H2O, 65 H2and He-balance.

3. Results and Discussion

By the temperature dependencies of the CO and CH4 outlet concentrations in selective CO methanation for all studied catalysts, it is seen, that Fe-based and Co(Cl)/CeO2 catalysts were inactive in CO and CO2 methanation reactions. Ni/CeO2 and Co/CeO2 catalysts were active in both CO and CO2 methanation, but showed low selectivity. Ni(Cl)/CeO2 catalyst showed the best performance in selective CO methanation, being less active than Ni/CeO2 and Co/CeO2, but considerably more selective.

XRD, TEM and EDX analysis showed the presence of chlorine on the surface of Ni(Cl)/CeO2, even the CeOCl particles (Table 1). Thus the observed differences in catalytic behavior of Ni-based catalysts could be associated with chlorine influence.

The TOFs calculated for Ni/CeO2 and Ni(Cl)/CeO2 catalysts at 210 °C (at this temperature CO conversion was < 15 % and CO methatation selectivity was 100 %) were similar (Table 1). These data mean, that Ni/CeO2 and Ni(Cl)/CeO2 catalysts exhibited similar activity in CO methanation. In other words, the presence of chlorine does not significantly influence on the CO methanation activity, but it dramatically inhibits the CO2hydrogenation activity, thereby promoting catalyst selectivity.

Table 1.Ni-based catalyst's characterization.



Xa, wt.%

DXRDb, nm

DMc, nm

TOF×103, s-1




























aPhase mass fraction according to the XRD analysis; bAverage particle size determined by the XRD analysis; cAverage size of metal particles according to the pulse CO chemisorption data.

 Based on the data obtained, the nature of the active centers, origin of the observed activity order and probable mechanisms of CO and CO2 methanation over Ni/CeO2 and Ni(Cl)/CeO2catalysts are discussed.

4. Conclusions

Catalytic properties of Ni-, Co- and Fe/CeO2 catalysts, prepared from nitrate and chloride precursors, in the selective CO methanation were studied. The Ni(Cl)/CeO2 catalyst, prepared from NiCl2 precursor, was the most efficient. This phenomenon could be explained by ceria surface blocking by chlorine species and appropriate inhibition of CO2hydrogenation activity.


This work was partially supported by the RFBR Grant 14-03-00457-a and MES (Russia).


[1] М.М. Zyryanova, P.V. Snytnikov, R.V. Gulyaev, Yu.I. Amosov, A.I. Boronin, V.A. Sobyanin, Chem. Eng. J. 238 (2014) 189.

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