Carbonization under pressure

Carbonization under pressure was reviewed by being classified into three routes: carbonization of the precursors under pressure of their decomposition gases, carbonization under hydrothermal conditions, and reduction of pressurized CO2. Carbon materials with different structures and nanotextures were formed with relatively high yield under pressure, but obtained as a mixture in most cases. In this review, the formation conditions of carbon spheres in pure and an individually separated state are discussed by focusing on the temperature–pressure conditions and the chemical composition of the precursors used.