Fabrication of porous Pt–Pd electrodes using solid state interdiffusion

Partial burnt off process of sacrificial material while fabricating porous electrode for gas sensors and fuel cells brings uncertainties about reaction of gas species with remained sacrificial material. Here, efforts were devoted to fabricate a porous electrode with high electrical conductivity without using sacrificial carbon material. To do so, bilayers of Pt/Pd were deposited over Yttria Stabilized Zirconia substrate and thermally treated at 500 °C for different annealing times. As a result of annealing, solid state interdiffusion between Pt and Pd was activated resulting to generation of Pd accompanied with pores on the surface of Pt layer. Moreover, 10 min annealing leads to higher electrical conductivity of intermixed layer which is most probably due to a reduction in grain boundary resistivity of the host material. It has been shown that 10 min annealed bilayers of Pt/Pd exhibit promising characteristics in terms of porosity and electrical conductivity. It was concluded that solid state interdiffusion was introduced as an effective method to fabricate porous conductive layers which has potential applications in gas sensors and fuel cells.