Hairy Foam Catalysts – towards control at the catalytic site

Metal Foams (surface area <1m²/g) are promising materials as catalyst support to overcome pressure drop in fixed bed reactors and to optimize hydrodynamics. The demands of catalysis like high surface area and porosity on metal foams can be achieved by growing Carbon Nano Fibers (CNFs). CNF layers on foam surface, designated as ‘hairy foam’, can provide high macro-porosity and low tortuosity. These properties of CNF layers can prevent any concentration gradients, thereby providing efficient mass transfer. A stable CNF layer was prepared on Ni foam surface, and the good attachment of CNFs is due to the embedment of CNF roots into a microporous C-layer which was formed between Ni surface and CNF layer (figure 1).

The aim of the project is to test the suitability of hairy foam catalysts for a liquid phase catalytic reaction in a fixed bed reactor (scheme 1) and to compare with the conventional porous catalysts by considering a very fast reaction such as nitrite reduction to N₂ where large effects of concentration gradients are expected along the catalyst particle.