Pd and Pd-Pt catalysts supported on SnO2 and c-Al2O3: Kinetic studies of wet lean methane combustion

Kinetic investigation of methane combustion on hydrothermally aged SnO2 and Al2O3 supported 1 wt% Pd and 1 wt% Pd-Pt(1:1) catalysts is reported in the presence of 5 and 10 vol% H2O. First-order to CH4, acti-vation energy of 143 kJ/mol and -1 order to H2O were observed for Pd/Al2O3. Both Pd-Pt catalysts demonstrated -1 order to water and activation energies of 128 kJ/mol, proposing the choice of support is inconsequential with Pt addition from the viewpoint of the activation energy. Pd/SnO2 illustrated -0.2 order to H2O. A rate law was suggested with two active sites, one affected by H2O with -1 order and acti-vation energy of 140 kJ/mol, and the other unaffected by water with activation energy of 88 kJ/mol. Turnover frequencies at wet conditions at 425 degC were found in the order of Pd/Al2O3(x) < Pd/Sn O2(24x) < Pd-Pt/ Al2O3(102x) < Pd-Pt/SnO2(275x). The Pd-Pt/SnO2 catalyst also demonstrated the least deactivation during hydrothermal ageing.(c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the kinetic behavior of methane combustion on hydrothermally aged SnO2 and Al2O3 supported 1 wt% Pd and 1 wt% Pd-Pt(1:1) catalysts in the presence of 5 and 10 vol% H2O. Different reaction kinetics and activation energies were observed for the catalysts depending on the support material and Pt addition. The Pd-Pt/SnO2 catalyst demonstrated the highest turnover frequency and the least deactivation during hydrothermal aging.