Development of Mn-modified Hexagonal YbFeO₃ Catalyst for Reducing the Use of Precious Metal Resources

Abstract

Mn-modified hexagonal YbFeO₃ (Mn-YFO) synthesized by a solvothemal method is found to have a higher catalytic activity for C₃H₈ or CO oxidation than noble metal catalyst, Pd/Al₂O₃. The catalytic activity is mainly due to amorphous MnO_x species located on ab plane of the hexagonal lattice. A small amount of Pd loading on Mn-YFO drastically enhances the catalytic activity; that is, 0.5 wt% Pd/Mn-YFO shows excellent activity for CO oxidation that exceeds the activity of 2.0 wt% Pd/Al₂O₃. The Pd loading dramatically improves the reducibility of the MnO_x species and also CO adsorption to Mn-YFO. Thus, we demonstrate that an extremely small amount of Pd species plays a role as a promoter for the catalytic and reduction functions of the MnO_x species on Mn-YFO. It is expected that the establishment of such promoter effect will provide a novel guideline for reducing the use of precious metal resources.