A cell structure is provided that is (i) capable of handling, on inner and outer surfaces, heat transfer requirements of heat exchangers and/or be a substrate for coatings for catalytic reactors, (ii) able to be easily combined and interconnected into a variety of shapes, and (iii) may be created in an additive manufacturing process. The provided cell structure may be replicated and interconnected with other cell structures to create lattice structures in a variety of shapes. Accordingly, the cell structure may be used to build a heat exchanger or catalytic reactor that has reduced weight compared to traditional architectures.