A new electroless plating approach to generate a porous metallic coating is described in which a metal is electrolessly deposited on a surface. Microparticles in the metal are removed to leave pores in the metal coating. Another method of forming electroless coatings is described in which a blocking ligand is attached to the surface, followed by a second coating step. The invention includes coatings and coated apparatus formed by methods of the invention. The invention also includes catalyst structures comprising a dense substrate and a porous metal adhered to the dense substrate, which is further characterized by one or more of the specified features.