•MgO nanoparticles are used as a sacrificial template to construct the porous anode.•The DMFC with porous anode exhibits a significant increase in catalyst utilization.•The DMFC with 50% reduced anode catalyst loading exhibits an enhanced performance.Simple addition of magnesium oxide (MgO) nanoparticles as a sacrificial pore-former into the catalytic layer (CL) and micro-porous layer (MPL) in the anode of a membrane electrode assembly (MEA) leads to the formation of porous anodic structure, thus greatly enhancing the performance of a passive direct methanol fuel cell. At the same PtRu(1:1) loading of 2.0 mg cm−2, the MEAs with porous CL and with both porous MPL and CL exhibit the maximal power densities of 37.0 and 43.7 mW cm−2 at a temperature of 25 °C and with 3 M of methanol solution, respectively. When the PtRu loading decreases to 1.0 mg cm−2, the maximum power density of an MEA with both porous MPL and CL is ca. 32.8 mW cm−2, which is even higher than that of a conventional MEA with a PtRu loading of 2.0 mg cm−2. The improved performance of the novel MEA can be ascribed to an increased electrochemical surface area, a decreased charge-transfer resistance as well as an efficient mass transfer of methanol after the formation of porous structure in the anode. The present work provides a very simple but very effective way to reduce the dosage of the noble metal catalysts for fuel cells.

•An integrated anode structure based on a microporous titanium plate is developed.•The maximum power density of 40 mW cm−2 for passive DMFCs is obtained at 25 °C.•The volumetric energy density of 489 Wh L−1 is obtained with neat methanol.•Over 90 h of operation is conducted with no obvious performance degradation.A microporous titanium plate based integrated anode structure (Ti-IAS) suitable for passive direct methanol fuel cells (DMFCs) fueled with neat methanol is reported. This anode structure incorporates a porous titanium plate as a methanol mass transfer barrier and current collector, pervaporation film for passively vaporizing methanol, vaporous methanol cavity for evenly distributing fuel, and channels for carbon dioxide venting. With the effective control of methanol delivery rate, the Ti-IAS based DMFC allows the direct use of neat methanol as the fuel source. In the meantime, the required water for methanol–oxidation reaction at the anode can also be fully recovered from the cathode with the help of the highly hydrophobic microporous layer in the cathode. DMFCs incorporating this new anode structure exhibit a power density as high as 40 mW cm−2 and a high volumetric energy density of 489 Wh L−1 operating with neat methanol and at 25 °C. Importantly, no obvious performance degradation of the passive DMFC system is observed after more than 90 h of continuous operation. The experimental results reveal that the compact DMFC based on the Ti-IAS exhibits a substantial potential as power sources for portable applications.

Polypyrrole nanowire networks (PPNNs), as anodic micro-porous layer (MPL) of passive direct methanol fuel cells (DMFCs), are grown in-situ on the surface of carbon paper through an electrochemical polymerization. Passive DMFC with the novel MPL achieves a 28.3% increment in maximum power density from 33.9 mW cm−2 to 43.5 mW cm−2 compared with the conventional layer with similar PtRu(1:1) loading of 2.0 mg cm−2 and operating with 4 M methanol solution at 25 °C. When the PtRu loading is decreased to 1.0 mg cm−2, the maximum power density of the DMFC still reaches 34.3 mWcm−2, which shows a comparative value with the conventional layer. The enhanced performance should be ascribed to the introduction of PPNNs, significantly improves catalyst utilization and mass transfer of methanol on the anode.