(532f) CO Preferential Oxidation and Methanation Catalysts and Their Performance for CO-Cleanup of Hydrogen-Rich Stream

In the last two decades, CO preferential oxidation (CO PROX) and CO preferential methanation (CO MET) are assumed as the most feasible reactions for CO removal from H₂-rich reformate for low temperature polymer electrolyte membrane fuel cells (LT PEMFC) feeding applications. Despite the existing advantages and disadvantages, both processes provide CO-cleanup to 10 ppm.

The present report summarizes the results obtained during a systematic study of catalysts, their performances and fundamental principles of the preferential CO oxidation and preferential CO methanation reactions. Catalytic performance of the prepared systems in a form of grains in the fixed-bed continuous flow reactor was studied. The most attention is concentrated on Cu/CeO₂ catalysts and their operation in a micro-channel reactor in preferential CO oxidation [1,2], and on Ni/CeO₂ catalysts supported over corrugated metal gauzes and their operation in a milli-channel reactor [3,4]. The role of nickel precursor was investigated and the positive effect of chlorine on the catalyst selectivity was demonstrated. The catalysts were characterized by BET, XRD, XPS, TEM, EDX, TPR and TPD techniques.

The effect of internal diffusion was estimated and the optimum grain size/coating thickness was found [8].

Based on the results obtained, the composition and structure of the catalysts’ active components were determined, and reasonable suggestions on the reaction mechanisms of CO PROX and CO MET were made. The CO PROX and CO MET efficiencies were discussed comparatively.

The selected copper and nickel-ceria based catalyst provides efficient CO cleanup of H₂- rich gas streams suitable for feeding power generating units on the base of LT PEMFC.

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

References

[1]   P.V. Snytnikov, M.M. Popova, et al., Appl. Catal. A. 350 (2008) 53.

[2]   P.V. Snytnikov, D.I. Potemkin, et al., Chem. Eng. J. 160 (2010) 923.

[3]   M.M. Zyryanova, P.V. Snytnikov, et al., Chem. Eng. J. 176-177 (2011) 106.

[4]   M.M. Zyryanova, P.V. Snytnikov, et al., Chem. Eng. J. 238 (2014) 189.

[5]   P.V. Snytnikov, V.A. Sobyanin, et al., Appl. Catal. A: General 239 (2003) 149.

[6]   D.I. Potemkin, Yu.V. Shubin, et al., Catal. Today 235 (2014) 103.

[7]   P.V. Snytnikov, S.D. Badmaev, et al., Int. J. Hydrogen Energy 37 (2012) 16388.

[8]   D.I. Potemkin, P.V. Snytnikov, et al., Kinet. Catal. 52 (2011) 139.