Cathodic Pt/C catalyst degradation for a direct dimethyl ether fuel cell (DDFC) has been investigated after a 70.5 h galvostatic operation at 60 C-omicron under ambient pressure. The cathode electrochemical active surface (EAS) reduces from 349 to 267 cm(2) me Pt after durability test. Cathode EAS loss is associated with the growth of Pt catalyst particles. XRD and TEM results show that the particle size of cathodic Pt catalyst increases from an original value of 3.0 nm to 5.4 nm. Furthermore, the anode failure accelerates dimethyl ether (DME) crossover, and consequently, poisoning of catalyst by absorbed DME and/or intermediates aggravates the degradation of cathodic Pt/C catalyst. The effect of anode degradation on the long-term performance of DDFC has been reported in companion article (Part I). (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.