Dense palladium membranes have increasing interest for ultra-pure hydrogen production compared to established technologies such as pressure swing adsorption and cryogenic distillation, allowing the separation in one step with no associated energy consumption. Alloying elements are used in combination with palladium in these membranes to change the membrane properties. This article presents a review of palladium alloy membranes for hydrogen purification, including permeability data and other relevant characteristics of the alloys. Further developments in this research field are expected to focus on the use of ternary alloys with enhanced physical and chemical properties, and the use of computational methods to enable a faster screening of promising alloys.

This Spotlight article presents the state-of-the-art of electrospray deposition technique applied to the fabrication of proton exchange membrane fuel cell (PEMFC) components, mainly focusing on catalyst layers in gas diffusion electrodes. The atomization of a suspension of particles over a substrate under the influence of a strong electric field results in the growth of a film with macroporous morphology and many interesting properties. This so-called electrospray deposition has reported many noteworthy beneficial effects for the fabrication of the catalyst layers of gas diffusion electrodes of PEMFCs. The electrosprayed catalyst layers prepared from suspensions of catalyst particles and ionomers present a dendritic macroporous morphology with superhydrophobic character that improves the water management inside the cell and increases the performance by ∼20% with respect to standard electrodes prepared by airbrushing. Other interesting effects observed with electrosprayed catalyst layers are increased catalyst utilization and water absorption capabilities of the ionomer, improved performance under nonhumidified conditions, and a reduction in catalyst degradation. In addition, the electrospray deposition decreases platinum losses during fabrication thanks to the attractive electrostatic forces between the ion mist and the substrate compared with regular ink-based spray methods.