CO and C3H8 total oxidation over Pd catalysts supported on commercial Ce-Zr solid solution: Effects of the calcination temperature and hydrothermal treatment

Abstract

A series of Pd catalysts supported on commercial Ce-Zr solid solution(Pd/CZ) calcined at different temperatures( 750, 900 and 1050 °C) was prepared via an incipient wetness impregnation method. The activities of the fresh and hydrothermally aged Pd/CZ catalysts were tested for total oxidation of CO and C3H8. For CO oxidation, the activity of either fresh or aged Pd/CZ catalysts decreased with the elevating of calcination temperature of CZ support, with a fresh catalyst calcined at 750 °C possessing the highest activity and hydrothermal stability. For C3H8 total oxidation, the activity of Pd/CZ catalysts could be improved by increasing the calcination temperature of support. However, the aged Pd/CZ catalysts showed higher activity than corresponding fresh Pd/CZ catalysts. The turnover frequency( TOF) over Pd/CZ catalyst for CO oxidation increased with increasing reduction ability of the catalysts, with a fresh catalyst calcined at 750 °C having the highest value(0.27 s−1). However, the TOF of Pd/CZ catalyst for C3H8 total oxidation was mainly affected by the size of Pd particles, and large Pd particles possessed a higher activity, with the highest TOF value(0.96 s−1) obtained over an aged catalyst calcined at 1050 °C.