Non-thermal plasma (NTP) technology is one of the strategies with the most potential for the degradation of volatile organic compounds. Exploring the combination of plasma and catalysts in one system is of considerable significance to improve energy efficiency and decrease harmful by-products. The current geometrical design of monolithic catalysts is not optimal due to the limitations of traditional manufacturing processes. Here, the use of material extrusion additive manufacturing, followed by debinding and sintering to construct alumina monolithic catalysts with two-dimensional channels is suggested. A new feedstock material was adapted to the additive manufacturing process, and Al ₂O ₃ structures with unique axial and radial channels coated with Mn-Co nanospheres were successfully prepared for the plasma-catalytic degradation of toluene. The monoliths with radial and axial channels considerably increased energy efficiency with a minor increase in by-products. This work demonstrates the advantages of using additive manufacturing and provides a general strategy for the design and fabrication of monolithic catalysts with two-dimensional channel structures for heterogeneous catalysis.