The present disclosure provides improved films/coatings (e.g., catalyst films/coatings), and improved assemblies/methods for fabricating such films/coatings. More particularly, the present disclosure provides advantageous assemblies/methods for fabricating or synthesizing catalytic material (e.g., catalytic nanostructures) in flame and depositing the catalytic material onto substrates. The present disclosure provides improved catalytic nanostructures, and improved assemblies and methods for their manufacture. In exemplary embodiments, the present disclosure provides for methods/assemblies for synthesizing electrocatalytic nanostructures in flame and depositing such material or catalyst onto different substrates or supports. As such, the present disclosure provides advantageous assemblies that are configured and dimensioned to deposit fully dense, controlled porosity films (e.g., films of metals and oxides or core-shell particles) onto different substrates.