Organically complexed nanocatalyst compositions are applied to or mixed with a carbon-containing fuel (e.g., tobacco, coal, briquetted charcoal, biomass, or a liquid hydrocarbon like fuel oils or gasoline) in order to enhance combustion properties of the fuel. Nanocatalyst compositions can be applied to or mixed with a solid fuel substrate in order to reduce the amount of CO, hydrocarbons, and soot produced by the fuel during combustion. In addition, coal can be treated with inventive nanocatalyst compositions to reduce the amount of NOx produced during combustion (e.g., by removing coal nitrogen in a low oxygen pre-combustion zone of a low NOx burner). The nanocatalyst compositions include nanocatalyst particles made using a dispersing agent. At least a portion of the nanoparticles is crystalline with a spacing between crystal planes greater than about 0.28 nm. The nanocatalyst particles can be activated by heating to a temperature greater than about 75° C., more preferably greater than about 150° C. and most preferably greater than about 250° C.