Self-oscillations of methane oxidation rate over Pd/Al2O3 catalysts: Role of Pd particle size

Oscillations of the methane oxidation rate were studied under methane-rich conditions on Pd/Al2O3 catalysts differing in Pd particle size. It was demonstrated that the temperature interval where oscillations occur narrows from 300-360 degrees C for the catalyst with Pd particle aggregates from 50-100 nm to 345-355 degrees C for the catalyst with isolated Pd particles of similar to 5 nm in size. At the same time, the period of oscillations showed similar to 6-fold increase. Structural transformations of Pd in the oscillation cycle were similar to those observed on bulk Pd used as a catalyst in the same reaction. (C) 2016 Elsevier B.V. All rights reserved.