High-optical-absorption carbon nanomaterial and preparation method thereof

The invention belongs to the field of optical absorption, and discloses a high-optical-absorption carbon nanomaterial which comprises carbon black and carbon nanowalls which grow on the surface of the carbon black through a chemical vapor deposition method and have light trapping capacity, and light absorption is achieved through gap structures between the walls. A radio frequency plasma enhanced chemical vapor deposition process is adopted, a mode of increasing plasma energy density by using inert gas is adopted, chemical bonds of carbon source gas are opened under the action of reducing gas hydrogen, a vertically arranged carbon nano wall is constructed on the surface of carbon black through the processes of nucleation, migration, orientation, growth and the like, the effective refractive index is close to 1, the material has good interface impedance matching, incident light penetrates through the surface of the material to enter clearance spaces of walls in an almost non-reflection mode and is finally abso