The performance of a vapor-fed low-temperature direct methanol fuel cell (DMFC) with Nafion proton exchange membrane has been analyzed and compared to identical fuel cell assembly supplied with liquid methanol diluted in water. The cell was subjected to a wide range of methanol concentrations and power loads. The potentiostatic measurements were correlated with the composition of gases released at the anode determined by on-line mass spectroscopy. Both Pt and PtRu catalysts supported on carbon were used at the DMFC anode while cathode comprised pristine Pt on C in all cases. It is demonstrated experimentally that although the vapor-fed system is generally more complex and require an additional source of heat or utilization of the waste reaction heat, it shows its potential to be more efficient and tunable than conventional liquid-fed FCs as well as more resistant to poisoning, even in the absence of ruthenium in the anode catalyst. Energy efficiency of 30% and power density exceeding 70 mW cm(-2) were achieved with Pt/C electrodes without any noticeable long-term degradation. (C) 2019 Elsevier Ltd. All rights reserved.