SnxZr1-xO2 solid solution-supported palladium catalysts were prepared and evaluated for the catalytic combustion of methane at low temperature. Catalyst Pd/Sn0.4Zr0.6O2 with the highest activity (T-90% = 378 degrees C, GHSV = 48,000 h(-1)) and excellent stability is one of the most active catalysts so far reported. The O-18-isotope exchange measurements show that both partial and complete heterogeneous exchanges, as well as oxygen release, were observed for all catalysts. Compared with other catalysts, Pd/Sn0.4Zr0.6O2 has much higher activity for oxygenexchange reaction and higher temperature for bulk palladium oxide decomposition. The results of TPR and O-18-isotope exchange experiments demonstrate that the excellent activity of Pd/Sn0.4Zr0.6O2 is due to its high oxygen mobility and moderate reducibility. XPS results indicate that the dispersion of Pd has little influence on the catalytic activity. (c) 2004 Elsevier B.V. All rights reserved.