Semi-continuous vapor grown carbon fiber mat and the producing method thereof

A method for fabricating a carbon fiber mat, comprising the following steps:

• providing a substrate with a catalyst on its surface;
• placing said substrate in a furnace;
• introducing hydrogen, ammonia, or a combination thereof into said furnace;
• adjusting the temperature of said furnace to 400° C. to 900° C. to proceed a heat treatment for 15 to 90 minutes, thereby obtaining nucleation points on said substrate, in which the density of said nucleation points distributes between 1˜50 sites/m2, and the size of said nucleation points distributes between 10˜2000 nm;
• adding a carbon-containing compound into said furnace and adjusting the ratio of said carbon-containing compound and said hydrogen, ammonia, or combinations thereof;
• and
• adjusting the temperature of said furnace to 600° C. to 1200° C. to crack said carbon-containing compound and reacting for 1 to 3 hours, and thereby forming a carbon fiber mat.