Significantly Improving the Activity of Methane Oxidation over a Pd-based Catalyst for Lean Natural Gas Vehicles by Catalyst Pre-treatment

Abstract

The activity of methane oxidation on the Pd/10YZ (10 wt.% Yttria-stabilized Zirconia) catalyst was significantly improved by pretreatment with a simulated emission gas mixture. The 90% methane conversion temperature T90 on the pre-treated Pd/10YZ-P was decreased by 49 °C. It was found that the pretreatment increased the content of PdO and active oxygen species on the catalyst surface. Meanwhile, larger crystalline PdO particles were formed after pretreatment. This enhanced the reducing property of the catalyst, resulting in a significant improvement of methane oxidation activity. The simulated exhaust gas pretreatment significantly improved the methane combustion activity of Pd-based catalysts. It is found that the pretreatment increases the content of PdO and active oxygen species on the catalyst surface. In addition, this pretreatment promotes the growth of Pd particles to form crystalline PdO, which is highly active for methane combustion.