The dynamic response performance of a proton exchange membrane fuel cell (PEMFC) significantly affects its durability and reliability. Thus, the improvement of the dynamic performance of PEMFC has become the key for prolonging the PEMFC life in fuel cell vehicle applications. In this study, RuO2 center dot xH(2)O is prepared by sol gel method, and then sprayed onto catalyst layers to promote PEMFC dynamic response performance. The prepared RuO2 center dot xH(2)O is characterized by TEM, which shows that the average particle size of RuO2 center dot xH(2)O is 8 nm and that the particulates are uniformly distributed. A 10-cell stack is assembled using membrane electrode assembly (MEA) with and without RuO2 center dot xH(2)O. This stack is studied under various loading cycles and operating conditions, including different air stoichiometries, relative humidities, and loading degrees. Results show that the steady-state performance of the MEA with RuO2 center dot xH(2)O is better than that in the MEA without RuO2 center dot xH(2)O with a decreasing relative humidity from 80% to 20%. A slower and more unstable dynamic response of the MEA without RuO2 center dot xH(2)O is observed as air stoichiometry and relative humidity decrease as well as the loading increase. Thus, RuO2 center dot xH(2)O improves the dynamic response performance, indicating that RuO2 center dot xH(2)O can buffer the voltage undershoot, improve the stability, and prolong the lifetime of the PEMFC stack. (C) 2013 Elsevier B.V. All rights reserved.