A comparison between deposition-precipitation and co-precipitation methods for the preparation of au-Ru/Fe 2O 3 nanostructure catalysts tested for partial oxidation of methanol

Abstract

In the present study, two preparation methods (deposition-precipitation and co-precipitation) for the synthesis of bimetallic Au-Ru/Fe 2O 3 catalysts were compared for their activity in partial oxidation of methanol (POM) to produce hydrogen. The Au-Ru/Fe 2O 3 catalysts were labeled as ARF-DP and ARF-CP for the catalysts prepa red by deposition precipitation (DP) and co-precipitation (CP), respectively. Prior to this study, the activity of bimetallic Au-Ru/Fe 2O 3 was compared with its monometallic Au/Fe 2O 3 and Ru/Fe 2O 3 catalysts. All the catalysts were characterized by ICP, BET, XRD, SEM, TEM and TPR analyses. BET analysis confirms that the ARF-DP have higher surface area than ARF-CP. TEM analysis depicts that small sized Au and Ru particles are well dispersed on the surface of the support in ARF-DP sample. TPR analysis illustrates that the reduction for Au and Ru oxides to metallic Au and Ru and Fe 2O 3 to Fe 3O 4 occur at a much lower temperature in the ARF-DP sample compared to ARF-CP sample. In the catalytic performance for POM to produce hydrogen, the bimetallic Au-Ru/Fe 2O 3 catalyst exhibits higher activity than that of its corresponding monometallic catalysts. The ARF-DP sample exhibits higher catalytic activity compared to ARF-CP sample. The higher activity of the ARF-DP catalysts has been explained in terms of strong metal-metal and metal-support interactions that facilitate the activation of sites, which leads to higher lattice oxygen mobility thereby influencing the reaction. © 2011 American Scientific Publishers.