Effect of different LaPO4 supports on the catalytic performance of Rh2O3/LaPO4 in N2O decomposition and CO oxidation

LaPO 4 has been used as a support to make supported catalysts in some investigations, but the effect of different LaPO 4 supports on the catalytic performance of supported catalysts has been rarely reported. In this work, conventional hexagonal LaPO 4 (LaPO 4 H) was prepared by precipitation, and hexagonal LaPO 4 nanowires (LaPO 4 HNW) was prepared by hydrothermal synthesis at 150   °C. Monoclinic LaPO 4 nanowires (LaPO 4 -MNW-220 and LaPO 4 -MNW-900) were prepared by hydrothermal synthesis at 220   °C or calcining LaPO 4 HNW at 900   °C. These samples were used to support Rh 2 O 3 via impregnation using Rh(NO 3 ) 3 as a precursor. The activities of these supported catalysts in N 2 O decomposition and CO oxidation follow the same sequence of Rh 2 O 3   /   LaPO 4 HNW   >   Rh 2 O 3   /   LaPO 4 H   >   Rh 2 O 3   /   LaPO 4 -MNW-220   >   Rh 2 O 3   /   LaPO 4 -MNW-900, i.e. , two hexagonal LaPO 4 supports are better than two monoclinic LaPO 4 supports in making active catalysts, and hexagonal LaPO 4 nanowires are better than hexagonal LaPO 4 composed of nanoparticles and short nanorods. The most active catalyst has highly dispersed Rh 2 O 3 species interacting strongly with the support, more oxygen-adsorption capacity, and more basic sites.