Catalytic static mixers, 3D printed from nickel alloys, were treated with etching or leaching solutions to activate their surfaces for use in hydrogenation of alkenes, aldehydes and nitro-groups. Their performance was benchmarked against industrial standard alumina catalysts, using a tubular continuous flow reactor. These novel structured catalysts were additively manufactured from printer-grade Monel and Inconel powders. Especially the Monel-type catalysts, consisting predominantly of nickel and copper by weight, presented a surface layer significantly enriched in nickel after the leaching protocol, which resulted in a high catalytic activity and a surprising selectivity towards unsubstituted double bonds.