Development of a catalytically activated heat exchanger with platinum-sulfur- and platinum-phosphorus-coating for the efficient release of pure hydrogen from LOHC systems

The aim of this work was the development of a catalytically activated heat exchanger for the application in the continuous dehydrogenation of perhydro benzyltoluene (H12-BT) to produce pure hydrogen. For this purpose, on the one hand the optimization of heterogeneous platinum catalysts by applying different phosphorus-modification methods was investigated. On the other hand, the design and implementation of a novel reactor concept, which exploits the direct heating of catalytic coatings, were addressed. The modification of platinum catalysts with phosphorus is accessible via a classical impregnation and also a solvent-free route. The resulting catalytic materials are highly active and temperature stable owing to geometric and electronic effects exerted by the deposited phosphorus species. Platinum-based powder catalysts were then transferred to suitable coating compositions that were applied on finned tubes. In the specially developed finned tube reactor concept the catalytic layer is directly heated by the finned tube substrate resulting in a power-dense (> 1 kW L-1) continuously operated H12-BT dehydrogenation unit that can provide hydrogen of fuel cell grade quality.