Influence of mixing time during glycine-nitrate process on the structural properties and reducibility of a dual-phase Ni-Cu-Mn spinel catalyst

The potential of Ni-Cu-Mn spinels as methane reforming catalysts for hydrocarbon-fueled solid oxide fuel cell (SOFC) applications is highly dependent on its catalytic properties, particularly reducibility. The reducibility of a spinel-structured catalyst is often correlated with its structural properties and fabrication processes. In this work, the structural properties and reducibility of a Ni-Cu-Mn spinel catalyst was evaluated on the basis of mixing time during the glycine-nitrate process. Phase analysis results showed that Ni0.4Cu0.6Mn2.0O4 and (Cu, Mn)(3)O-4 in normal or inversed spinel structures were observed in GNP-produced Ni-Cu-Mn spinel catalyst powders. Distortion in inverse spinel structures enhanced the reducibility of the spinel catalyst. Morphological analysis results showed that complete nitrate binding occurred at a minimum mixing time of 24 h and resulted in homogenous particle size distribution and uniform elemental distribution. Furthermore, the Ni-Cu-Mn spinel catalyst produced after 24 h of mixing was fully reduced at 450 degrees C. The reducing pattern of the Ni-Cu-Mn spinel catalyst produced after 24 h of mixing time showed strong metal-support interaction and the fast adsorption of reactants. These effects were due to either the distribution of divalent cations in octahedral sites or large amounts of bulk pores. In conclusion, a minimum mixing time of 24 h is sufficient to produce the desired structural properties and reducibility of Ni-Cu-Mn spinel catalysts for SOFC applications.

Automated summary

The catalytic properties of Ni-Cu-Mn spinels as methane reforming catalysts for hydrocarbon-fueled solid oxide fuel cell (SOFC) applications depend strongly on their reducibility, which is influenced by structural properties and fabrication processes. In this study, it was found that a minimum mixing time of 24 h during the glycine-nitrate process was sufficient to produce Ni-Cu-Mn spinel catalysts with desired structural properties and reducibility for SOFC applications. This was evidenced by phase analysis showing the presence of specific spinel structures and morphological analysis revealing homogenous particle size distribution and complete nitrate binding after 24 h of mixing.