Highly durable spray-coated plate catalyst for the dehydrogenation of perhydro benzyltoluene

Abstract

In this study, we introduce a new spray coating technique to produce porous catalytic layers for the dehydrogenation of hydrogen carriers. The composition of the sol–gel composite dispersion is adjusted by a design of experiments (DoE) approach in order to reach excellent spraying processability, high coating stability, and a high coating load. In this way, coatings with remarkably high thicknesses of up to 500 μm, good durability, and decent adherence on stainless steel substrates were achieved. Furthermore, the precise adjustment of the coating loads and thicknesses of the highly porous γ-alumina catalyst support coating is demonstrated using the developed approach. Coating of different line-of-sight geometries, e.g., corrugated plates, is also shown. The coated plates have been impregnated with platinum and tested in the highly endothermic dehydrogenation of perhydro benzyltoluene. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) revealed an increasing penetration depth of platinum into the coating layer with higher platinum loadings. For the dehydrogenation reaction, high surface related productivities of 0.8 mg_H2 min⁻¹ cm⁻² using a platinum loading of 3.7 wt% were reached, and the coatings proved completely mechanically stable under these hydrogen release conditions.