Extrusion-based additive manufacturing of three-dimensional MoSe 2 -nanosheet-coated TiO 2 hetero-structures for photocatalytic CO 2 reduction

Extrusion-based additive manufacturing (EAM) provides design freedom and facilitates the production of complicated structures that are often challenging to produce using conventional processing methods. In this study, a TiO 2 feedstock was developed by mixing TiO 2 with a binder and optimized for extrusion. To maximize the reaction efficiency, three-dimensional (3D) structures were designed for the application of photocatalytic CO 2 reduction. To further enhance the photocatalytic CO 2 reduction efficiency of the structure, MoSe 2 , a transition metal dichalcogenide (TMD), was hydrothermally synthesized on the TiO 2 surface to form a heterostructure. MoSe 2 , which is known for its affordability in fabrication heterostructures, high electrical conductivity, expanded light absorption range, and reduced bandgap, has the potential to enhance photocatalytic efficiency. The effectiveness of various TiO 2 –MoSe 2 3D structural designs for CO 2 reduction was evaluated. A custom-made stainless-steel reactor was used for CO 2 reduction under UV-vis irradiation, followed by gas chromatography analysis of the produced gases. The optimized structure exhibited remarkable CO 2 selectivity, reaching approximately 82%, demonstrating the feasibility of using EAM for fabricating 3D structures for photocatalytic CO 2 reduction.