Pd catalyst supported on ZrO2‐Al2O3 by double‐solvent method for methane oxidation under lean conditions

Abstract

AbstractThe Pd catalyst supported on the Zr0.5Al0.5O1.75 composite material was prepared by the conventional impregnation and double solvent impregnation method. The effects of preparation method on the catalytic properties of the Pd/Zr0.5Al0.5O1.75 catalyst for methane combustion have been investigated systematically. The measurement was evaluated in a multiple fixed‐bed continuous flow micro‐reactor by passing a gas mixture simulating the exhaust emissions from lean‐burn natural gas vehicles. The as‐prepared catalysts were characterized by CO chemical adsorption, transmission electron microscopy (TEM), hydrogen‐temperature programmed reduction (H2‐TPR),and X‐ray photoelectron spectroscopy (XPS) measurements. The results of TEM and CO chemisorption showed that the introduction of double solvent during the preparation of Pd/Zr0.5Al0.5O1.75 was beneficial for the dispersion of Pd nanoparticles and obtained superior resistance to the sintering of Pd on the surface of Zr0.5Al0.5O1.75. The H2‐TPR measurements demonstrated that the double solvent method increased the reducibility of the Pd catalyst. The XPS results further indicated that more active surface oxygen species also can be formed on the catalyst prepared via double solvent process. Thus, this catalyst exhibited better catalytic performance and hydrothermal aging resistance in the methane oxidation compared to its analogues with the same Pd content prepared by the conventional impregnation method.