貴金属使用量低減化を目指したMn修飾六方晶YbFeO3触媒の創製

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 MnOx 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 MnOx 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 MnOx 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.