Electrochemical oxidation of hydrolyzed poly oxymethylene-dimethyl ether by PtRu catalysts on Nb-doped SnO(2-δ) supports for direct oxidation fuel cells

Process Intensification Strategies for Power-to-X Technologies

Sector coupling remains a crucial measure to achieve climate change mitigation targets. Hydrogen and Power-to-X (PtX) products are recognized as major levers to allow the boosting of renewable energy capacities and the consequent use of green electrons in different sectors. In this work, the challenges presented by the PtX processes are addressed and different process intensification (PI) strategies and their potential to overcome these challenges are reviewed for ammonia (NH3), dimethyl ether (DME) and oxymethylene dimethyl ethers (OME) as three exemplary, major PtX products. PI approaches in this context offer on the one hand the maximum utilization of valuable renewable feedstock and on the other hand simpler production processes. For the three discussed processes a compelling strategy for efficient and ultimately maintenance-free chemical synthesis is presented by integrating unit operations to overcome thermodynamic limitations, and in best cases eliminate the recycle loops. The proposed intensification processes offer a significant reduction of energy consumption and provide an interesting perspective for the future development of PtX technologies.

Durability of Alternative Metal Oxide Supports for Application at a Proton-Exchange Membrane Fuel Cell Cathode—Comparison of Antimony- and Niobium-Doped Tin Oxide

In this study, the resistance to corrosion of niobium-doped tin dioxide (Nb-doped SnO2, NTO) and antimony-doped tin oxide (Sb-doped SnO2, ATO) supports has been probed for proton-exchange membrane fuel cell (PEMFC) application. To achieve this goal, ATO or NTO supports with loose-tube (fiber-in-tube) morphology were synthesized using electrospinning and decorated with platinum (Pt) nanoparticles. These cathode catalysts were submitted to two different electrochemical tests, an accelerated stress test following the EU Harmonised Test Protocols for PEMFC in a single cell configuration and an 850 h test in real air-breathing PEMFC systems. In both cases, the dissolution of the doping element was measured either by inductively coupled plasma mass spectrometry (ICP–MS) performed on the exhaust water or by energy dispersive X-ray spectrometry (X-EDS) analysis on ultramicrotomed membrane electrode assembly (MEA), and correlated to the performance losses upon ageing. It appears that the NTO-based support leads to lower performances than the ATO-based one, mainly owing to the low electronic conductivity of NTO. However, in the case of ATO, dissolution of the Sb doping element is non-negligible and represents a major issue from a stability point-of-view.