Construction of porous anode by sacrificial template for a passive direct methanol fuel cell

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.