Customizable Heterogeneous Catalysts: Nonchanneled Advanced Monolithic Supports Manufactured by 3D-Printing for Improved Active Phase Coating Performance

Abstract

Three-dimensional (3D)-printed catalysts are being increasingly studied; however, most of these studies focus on the obtention of catalytically active monoliths, and thus traditional channeled monolithic catalysts are usually obtained and tested, losing sight of the advantages that 3D-printing could entail. This work goes one step further, and an advanced monolith with specifically designed geometry has been obtained, taking advantage of the versatility provided by 3D-printing. As a proof of concept, nonchanneled advanced monolithic (NCM) support, composed of several transversal discs containing deposits for active phase deposition and slits through which the gas circulates, was obtained and tested in the CO-PrOx reaction. The results evidenced that the NCM support showed superior catalytic performance compared to conventional channeled monoliths (CMs). The region of temperature in which the active phase can work under chemical control, and thus in a more efficient way, is increased by 31% in NCM compared to the powdered or the CM sample. Turbulence occurs inside the fluid path through the NCM, which enhances the mass transfer of reagents and products toward and from the active sites to the fluid bulk favoring the chemical reaction rate. The nonchanneled monolith also improved heat dispersion by the tortuous paths, reducing the local temperature at the active site. Thus, the way in which reactants and products are transported inside the monoliths plays a crucial role, and this is affected by the inner geometry of the monoliths.