Exploring the 3D printing of molybdenum carbide-based catalysts for the reverse water gas shift reaction: A multi scale study

Abstract

A new methodology for preparing 3D printing molybdenum carbide-based catalysts with direct ink writing is presented. CO2 conversion experiments through the reverse water gas shift reaction showed that the catalytic behavior of 3D-MoxC/Al2O3 catalysts is controlled by the crystallite size and crystalline phase, which in turn were dependent on the Mo loading. The formation of cubic δ-MoC and hexagonal η-Mo3C2 was prevalent in small crystallite sizes at low loading of Mo, and α/β-Mo2C in larger crystallite sizes at high loading of Mo. Operando DRIFTS experiments points out that hydroxyl species present on the surface of Al2O3 play a major role in bicarbonate formation that leads to the formation of formates, which eventually decomposes to CO and H2O. The produced structures were mechanically stable and kept their structural and textural properties after reaction. Therefore, this work introduces new perspectives for scaling-up 3D printed structures based on molybdenum carbide.