Hydrolysis mechanism of YbB₂C₂ and the microstructure of the carbon derived from the hydrolysis reaction

Carbide-derived carbon (CDC) materials have gained great attention due to the excellent properties for various potential applications. Here, graphite crystal is formed during a room-temperature hydrolysis process of layered compound YbB2C2. The formation mechanism can be demonstrated by a YbB2C2 molecular cell: Yb3+ acts as a cathode where H2O molecule is reduced to H atom and OH- ion, while (B2C2)(3)- acts as an anode where OH- ion is oxidized to O atom. Then, YbB2C2 molecular cell begins to disintegrate, i.e., Yb3+ ion, B and C atoms dissociate from the molecular cell. The as-produced C atoms combine to form graphite crystal. The initial graphite crystal is a cabbage-like microsphere, and then it gradually disintegrates and transforms into layered graphite. In addition, YbB6, Yb-3(OH)(3)n (BO3)((3-n)) sol, hydrogen, hydrocarbons, and carbon oxides form simultaneously. Our method provides a general and inexpensive route to obtain carbide-derived graphite crystal. (c) 2023Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.