TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal catalyst particles are nickel, iron, cobalt, copper and/or molybdenum. Preferred Process: The process for the production of 3D carbon fiber structures having OCF covered with a network of secondary and tertiary carbon filaments comprises: depositing active metal catalyst particles on the surfaces of the recovered SCF; thermally decomposing a carbonaceous gas in an oxidant-free atmosphere over the surface of the heated SCF carbon fibers and recovering 3D carbon fibers having properties of OCF with straight SCF grown on the OCF surfaces and curly tertiary carbon filaments (TCF) (3) grown as branches on the surface of the straight SCF, hence realizing 3D carbon fibers. The process further comprises activating the recovered 3D carbon fibers containing SCF by exposure to steam or carbon dioxide. Preferred Components: The means are provided for activation of the recovered SCF in a second reaction chamber. The apparatus comprises: first chamber (a); means for supplying original carbon filament into and out of the first chamber; means (c); means (d); means (e); an intermediate reaction chamber is provided for the deposition of metal catalyst particles onto the surface of SCF; a second chamber for growing tertiary carbon filament (TCF) provided with means to both introduce CFG and the SCF with metal catalyst particles on the surface of the SCF; and means for recovery from the second chamber of the 3D carbon fibers which have the property of the TCF grown on the SCF which is originally grown on the OCF.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The carbonaceous gas is an aliphatic hydrocarbon compound or carbon monoxide. The aliphatic hydrocarbon is propane, methane or ethylene. EXAMPLE - A cylindrical quartz reactor was purged with argon gas, and the original carbon fiber was resistively heated to approximately 650 degrees C to desorb and decompose all the gases and organic compounds present on its surface. This was followed by the introduction of propane into the reaction chamber where it decomposed over the surface of resistively heated carbon fiber for 5 minutes. The carbon fiber with carbon filaments grown on its surface was removed from the reactor.