Manufacturing of a hierarchical carbon foam with tailored catalytically Me/MexOy particles. (September 2018)

• Record Type: Journal Article
• Authors: Marx, J.; Wilhelmy, F.; Beisch, H.; Fiedler, B.
• Is Part Of: Vacuum. Volume 155(2018)
• Page Start: 490
• Page End: 495
• Publication Date: 2018-09
• Subjects: CVD process -- Electron microscopy -- TGA -- Gibbs free energy -- Grain size distribution; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2018.06.052
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Carbon foams are characterised by their high specific surface areas (SSAs) in combination with ultra-low densities. Due to these unique properties, carbon foams are particularly suitable for applications such as catalysts, where high surface area is essential. Metals or metal oxides are added to the carbon structure to increase the catalytically effectiveness. In this study, we present a new and efficient manufacturing method, with the potential for a large-scale production resulting in a 3D hierarchical carbon foam with incorporated catalytically metal or metal oxides. The manufacturing starts with the preparation of a ceramic zinc oxide (ZnO) precursor powder containing catalytically active materials (Me/Mex Oy ), uniaxial pressing and sintering yielding to templates. The replication of the template morphology into a hollow carbon structure in the chemical vapour deposition (CVD) process, in which the catalytic materials remain in the carbon foam. Furthermore, the morphology of these structures and the grain size distribution are investigated using scanning electron (SEM) and transmission electron microscopy (TEM). The final amount of catalytically particles is analysed by thermal gravimetric analysis (TGA). Finally, the SSA of the synthesised carbon-based catalysts is measured by Brunauer-Emmett-Teller (BET) method. Highlights: 3D hierarchical carbon foam is produced in a two-step process, based on a ceramic template by its converting. Catalytic additives are chosen based on thermodynamical calculations and determining of Gibbs free energy. Catalytical metal/metal oxides were successful incorporated in the synthesised carbon structure. The main particle size is about 100 nm respective 10–30 nm. BET measurements shown a decreasing SSA of the carbon foam with an increased amount of catalytical particles.