NOVELTY - Controlling the activity of a tunable catalyst involves providing the catalyst including a ferroelectric substrate of finite thickness having two opposing surfaces, an electrode on one surface of the substrate, and a catalytically active material on the surface of the substrate opposing the electrode, where the substrate has a polarization; and subjecting the substrate to a controllable electric field to give rise to a modulation of polarization of the substrate. The modulation of the polarization controllably alters the activity of chemical species on the catalytically active material.    USE - For controlling the activity (including chemisorption, desorption, dissociation, and reaction) of chemical species (including hydrogen, carbon, oxygen, nitrogen, sulfur and their isotopes) on the catalytically active material of a tunable catalyst used in catalytic converters, fuel cells, Fischer-Tropsch synthesis, hydrogenation, oxidation/combustion, synthesis of methanol, nitric acid, sulfuric acid, ammonia, or hydrogen, petroleum refining/processing, alkylation, catalytic cracking, naphtha reforming, steam reforming for synthesis gas production, transesterification, olefin polymerization, non-olefin polymerization, electrolysis of water, dissociation of ammonia, reduction of nitrogen oxides to elemental nitrogen, and epoxidation (claimed).    ADVANTAGE - The method controls the properties of catalytic materials in real time during a chemical synthesis. The method improves the dissociation of carbon monoxide from the platinum surface. The controllable electric field can modulate the magnitude of the bulk polarization, and the direction of the bulk polarization, of the ferroelectric substrate. The polarization can be controllably switched in real time.    DETAILED DESCRIPTION - Controlling the activity of a tunable catalyst involves providing a tunable catalyst including a ferroelectric substrate of finite thickness having two opposing surfaces, an electrode on one of the surfaces of the ferroelectric substrate, and a catalytically active material on the surface of the ferroelectric substrate opposing the electrode; and subjecting the ferroelectric substrate to a controllable electric field to give rise to a modulation of a polarization of the ferroelectric substrate. The modulation of the polarization controllably alters the activity of chemical species on the catalytically active material. The catalytically active material is in the form of thin films, islands, lines, and/or nanoparticles. The catalytically active material comprises a transition metal and/or alloy, that can be deposited and/or grown as a film and/or nanoparticle, on the ferroelectric substrate. An INDEPENDENT CLAIM is included for a tunable catalyst comprising a ferroelectric substrate of finite thickness comprising two opposing surfaces, where the ferroelectric substrate has a polarization; an electrode on one of the surfaces of the ferroelectric substrate; and a catalytically active material on the surface of the ferroelectric substrate opposing the electrode, where the electrode and the catalytically active thin film are capable of subjecting the ferroelectric substrate to a controllable electric field to modulate the polarization of the ferroelectric substrate; and the modulation of the polarization is capable of controllably altering the activity of chemical species on the catalytically active material.