Role of Pellet Geometry Controlled by 3D Printing on Catalytic Performance of Mn–Na₂WO₄-Based Systems in Oxidative Coupling of Methane

Pellet catalysts dedicated to oxidative coupling of methane (OCM) were prepared with the assistance of 3D printing technology using the casting technique. In this approach, polymeric templates printed using digital light processing technology were applied for pellet catalyst shaping. Three series of cubic-type catalysts varying in external size and number of channels were produced by a one-step procedure of the templates filling with the paste containing Mn2O3, Na2WO4, α-Al2O3, and sodium silicate solution. The pellets containing 2 wt % of Mn2O3 and 5 wt % of Na2WO4 were characterized by X-ray fluorescence, X-ray diffraction, UV–vis diffuse reflectance, temperature-programmed reduction with H2, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques and tested in OCM. The pellet catalysts exhibited excellent catalytic performance and stability vs time on stream. It has been found that the size of the pellets and their geometry have an impact on the catalytic performance and pumping resistance through the catalyst bed (drop pressure).