A nanocatalyst composed of 10 wt% Pd supported on TiO2 was synthesized using one-step flame spray pyrolysis with a highly-quenched premixed stagnation flame. The as-prepared nanoparticles, having a mean diameter of approximately 10 nm, were then subjected to isothermal oxidation and reduction in a fixed bed reactor. The potential roles of Pd and PdO as well as possible synergistic effects between these two active species were explored during methane conversion. The lowest light-off temperature T-20 was obtained at a Pd ratio of 53% and this result can be reasonably explained based on a surface Pd-PdO site pair mechanism. Additionally, differences in the hysteresis behavior during methane oxidation were noted throughout a heating-cooling cycle over the temperature range of 200-600 degrees C, such that the degree of hysteresis was strongly correlated with the Pd ratio. (C) 2018 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.