NOVELTY - A catalyst composition (C1) for application to fuel substrate comprises primary catalyst atoms selected from chromium, manganese, iron, cobalt, nickel, copper, zirconium, tin, zinc, tungsten, titanium, molybdenum and vanadium; at least a portion of the catalyst atoms forming a crystal lattice having several crystal planes exposed at its surface, where spacing between the planes is greater than 0.28 nm; and organic dispersing agent molecules bonded to a portion of catalyst atoms, where each molecule includes functional group such as hydroxyl, carboxyl, carbonyl, amine and acyl halide.    USE - As catalyst composition for application to a fuel substrate e.g. tobacco, coal, briquetted charcoal, wood, biomass, fuel oil, diesel, jet fuel, and gasoline to modify the combustion properties of the fuel (claimed).    ADVANTAGE - The composition improves the combustion properties of fuels; reduces pollutants generated during combustion. The nanocatalyst particles are stable and hence the suspension formed is easily stored and transported without agglomeration of the nanocatalyst particles. The catalyst composition can be prepared, stored and then transported as needed thus obviating the need to form the catalyst on-site at the time it is applied to a fuel substrate. The nanocatalyst composition increases catalyst efficiency thereby allowing for lower catalyst loading within a fuel composition and/or increasing catalyst activity. The dispersion and stability of the nanocatalyst particles increases the activity of the catalyst such that lower amounts of the catalyst can be loaded while still providing a desired level of catalytic activity. The nanocatalyst composition reduces the formation of carbon monoxide and nitric oxide in other carbon-containing fuels such as coal, briquette charcoal, wood and biomass.    DETAILED DESCRIPTION - A catalyst composition (C1) for application to a fuel substrate to modify the combustion properties of the fuel comprises several primary catalyst atoms selected from chromium, manganese, iron, cobalt, nickel, copper, zirconium, tin, zinc, tungsten, titanium, molybdenum and vanadium; at least a portion of the catalyst atoms forming a crystal lattice having several crystal planes exposed at its surface, where the spacing between the crystal planes is greater than about 0.28 nm; and several organic dispersing agent molecules bonded to at least a portion of the catalyst atoms, where each dispersing agent molecule contains at least one functional group selected from hydroxyl, carboxyl, carbonyl, amine, amide, nitrile, nitrogen having a free lone pair of electrons, amino acid, amine, thiol, sulfonic acid, sulfonyl halide and acyl halide. The dispersing agent molecules are bonded with the catalyst atoms through at least one functional group. INDEPENDENT CLAIMS are included for the following:    (1) a fuel composition having modified combustion properties, comprising fuel substrate; and several nanocatalyst particles on and/or mixed with the fuel substrate, where the nanocatalyst particles have a size less than 1 micron and is comprised of catalyst (C1); and    (2) preparation of metal catalyst nanoparticles for use in modifying combustion properties of a fuel involving: providing the several primary catalyst atoms; providing a dispersing agent comprising several molecules having at least one functional group selected from hydroxyl, carboxyl, carbonyl, amine, amide, nitrile, nitrogen having free lone pair of electrons, amino acid, amine, thiol, sulfonic acid, sulfonyl halide and acyl halide; reacting the catalyst atoms with the dispersing agent in a solvent to form several complexed catalyst atoms; causing or allowing the complexed catalyst atoms to form nanocatalyst particles having a size less than about 1 micron; and activating the catalyst atoms by heating the nanocatalyst particles to a temperature greater than 75 degrees C.