Monolithic composites with geometry controlled by polymeric 3D printed templates: Characterization and catalytic performance in OCM

Abstract

Designed in computer-aided design (CAD) software and three-dimensional (3D) printed in Digital Light Processing (DLP) technology polymeric templates were applied to control in micron-scale macroporosity, shape and size of Mn-containing monolithic composites. The monoliths with 0.5, 1, 2, 5 and 10 wt% of Mn were characterised by X-ray fluorescence (XRF), X-ray diffraction (XRD), diffuse reflectance UV–Vis spectroscopy (UV–Vis DRS), temperature-programmed reduction with hydrogen (H2-TPR), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) techniques and tested in oxidative coupling of methane (OCM). The effect of Mn loading as well as an influence of channels size and their density on the catalytic performance in OCM was carefully investigated. In a series of monoliths containing 35 channels with different diameters (0.4, 0.6, 0.8 and 1.0 mm) the maximum conversion of methane vs. selectivity to C2+ hydrocarbons was observed for the samples with channels size 0.6 and 0.8 mm. Moreover, modification of the channels density had also a beneficial effect on the catalytic performance in OCM. Yield of C2+ grew with the increase in the number of channels in the monolith.