Nanoparticles of calcium hydroxide having a dumbbell shape, wherein the dumbbell shape has rounded ends separated by a narrow central portion, wherein a ratio of a largest width of the central portion to a largest width of the rounded ends is 0.30 to 0.75, a length is in the range of 500 nm to 1100 nm, the largest width of the narrow central portion is 100 to 250 nm, and the largest width of the narrow central portion is 100 to 250 nm. The nanoparticles have a mesoporous structure and are made up of subparticles that have a size of 5 to 75 nm. A method of making the nanoparticles from calcined calcium carbonate sources is disclosed. Also disclosed is an enhanced fuel containing the nanoparticles.