TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In the method for synthesizing a porous carbon-based film, the porous carbon film is self-supporting. The porous film is a nanoporous carbon film. The inorganic material is a metal oxide, where the inorganic material is colloidal silica. The particles of inorganic material are spherical in shape. The average size of the particles of the inorganic material is 1 nm to 10 mu m, preferably 2-100 nm. The carbon precursor is carbon-generating materials selected from pitch, carbohydrate, alcohol, polymer, oligomer, polycyclic aromatic hydrocarbons, and their combination. The mass ratio of the carbon precursor to the inorganic material is 1/50 to 5/1. The mixture further comprises a surfactant, where the surfactant is thermally decomposable, and where the surfactant is selected from poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer (PEO-PPO-PEO), Polysorbate 80, partially-hydrolyzed polyvinyl alcohol (PVA), and their combination. The mixture further comprises a binder, where the binder is water-soluble and thermo-decomposable, and where the binder is selected from polyvinyl butyral-co-vinyl alcohol-co-vinyl acetate, polyacrylamide, PVA, and their combination. The mass ratio of inorganic material to binder is 1/10 to 10/1. The mixture further comprises a plasticizer selected from water, polyethylene glycol, polyol, polyamine or their combination, where the plasticizer is 1,3-propanediol. The mass ratio of the plasticizer to the inorganic material is 1/10 to 10/1. The mixture further comprises additives selected from an alcohol, a phenolic, an iron compound, a silicon compound other than silica, a titanium compound other than titania, carbon nanotubes, graphene, graphene oxide, carbon nanofibers, a polymer, and a plastic, where the additive is n-butanol. The weight percentage of the additive within the mixture is less than 50%, preferably less than 10%. The water content of the mixture is 1-99%, preferably 40-90% in weight. The film is exposed to a temperature of 500-1500 degrees C for 0.1-48 hours in step (e). The temperature is increased from room temperature to 500-1500 degrees C at a rate of 0.1-100 degrees C/minute. The film is exposed to a temperature of 100-500 degrees C for 0.1-48 hours prior to exposure of the film to a temperature of 500-1500 degrees C in the step (e). The film is placed between two plates or between two other films during step (e). The film is held under a pressure during step (e), where the pressure varies during step (e). Preferred Nanoporous Carbon-Based Film: The network further comprises pores having a diameter greater than zero and less than 2 nm or 0.1 mu m to 100 Mm. A gradient in porosity is present across the film. The film is electrically conductive. The surface of the film is modified by functional groups selected from pentafluorophenyl, aminophenyl, nitrophenyl, phenyl sulfonic acid, and their combination. The film is self-supporting. The film is supported by carbon fibers, a glass grid or glass fibers. A modified nanoporous carbon-based film comprises the nanoporous carbon-based film defined above, where the carbon-based film is modified with a bio-material selected from enzymes, proteins, antibodies, bacteria, DNA, RNA, and their combination, or where the film is doped with nitrogen, boron, phosphorus, or their combination. A porous carbon-based film comprises an open network of interconnected pores, the network comprises pores having a diameter greater than 100 nm and less than or equal to 100 mu m. Preferred Supported Catalyst: The metallic nanoparticles are nanoparticles selected from platinum (Pt), palladium (Pd), iridium (Ir), nickel (Ni), gold (Au), cobalt (Co), ruthenium (Ru), rhodium (Rh) and their combination. The metal oxide nanoparticles are nanoparticles selected from a ruthenium oxide, an iridium oxide, a titanium oxide, a tantalum oxide, a cobalt oxide, an iron oxide, and their combination. EXAMPLE - No suitable example given.