The fabrication of electrodes and catalysts by 3D printing (i.e., additive manufacturing (AM)), is very convenient for fast prototyping and screening of materials, being possible to speed up the investigation of new geometries and compositions at a lower cost. Among the various AM techniques, Direct Ink Writing (DIW, Fig. 1a), also called robocasting, yields 3D structures that may become advantageous for electrocatalysis, owing to the increased surface area of the electrodes. [1] For applications that do not require excellent mechanical properties, such structures are certainly disrupting [2], as demonstrated in the energy sector for 3D battery and supercapacitor electrodes.[1] In this work, we have used a metallic- (steel) and ceramic- (TiO₂) based ink, to print freestanding steel cathodes and TiO₂ photocatalysts, respectively. First, the rheological properties of the inks were studied to optimize the fabrication of the materials. Once obtained, the pieces were subjected to thermal post-processing, aiming to evaporate the water retained in the extruded paste (i.e., drying step), decompose the organic binder (i.e., debinding step), and finally confer the mechanical cohesion and continuity (i.e., sintering step). The first material under study was a robocasted steel cathode (6 cm²), fabricated from a mixture of steel powder and Pluronic-F127 hydrogel. The sintered steel (Fig. 1b) was characterized (Fig. 1c) and then employed as an electrocatalytic cathode for the removal of nitrate (2 mM), a worrisome contaminant in groundwater at farming areas, from model water solutions. The printed steel cathode was superior to a commercial casted mild steel, yielding a faster denitrification (> 95% vs 40% after 240 min at 150 mA and natural pH 6.5) and showing a good recyclability for at least 3 runs. On the other hand, 3D printing of ceramics is the latest trend in additive manufacturing [3], and the second material under study was a TiO₂ photocatalyst (1 cm2), fabricated from a mixture of TiO₂ powder and the same hydrogel. It was employed as a suspended piece to carry out the degradation of an organic pollutant (10 mg/L) under UVA and solar irradiation, showing the feasibility of heterogeneous photocatalysis to decontaminate water without requiring the post-treatment separation/recovery that limits the interest of this technology when using powdery photocatalyst.