NOVELTY - Carbon nanotube (CNT)-mesoporous silica composite comprises CNTs and mesoporous silica.    USE - The CNT-mesoporous carbon composite is useful as a catalyst support in an electrode of a fuel cell (all claimed).    ADVANTAGE - The CNT-mesoporous carbon composite has a high electrical conductivity, and improves performance of a fuel cell. The catalyst support has large surface area due to high porosity and a high electrical conductivity for the flow of electrons.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) preparing a CNT-mesoporous silica composite, comprising dissolving a surfactant in water and adding CNTs to form a mixture, adding a silica source and water to the mixture to form a solution, adding an acid to the solution to adjust the pH of the solution, stirring the solution, heating the solution to obtain powders, separating the powders from the solution, washing the powders at least one time and calcining the powders;    (2) preparing a CNT-mesoporous carbon composite, comprising preparing a carbon precursor sol by mixing a polymerizable carbon-containing compound with a carrier, impregnating a CNT-mesoporous silica composite with the carbon precursor sol, polymerizing the carbon precursor sol penetrated into the CNT-mesoporous silica composite to obtain a carbon precursor penetrated into the CNT-mesoporous silica composite, thermally decomposing the carbon precursor to obtain a carbon structure penetrated into the CNT-mesoporous silica composite and treating the carbon structure penetrated into the CNT-mesoporous silica composite with a solution capable of dissolving silica to remove the silica;    (3) a supported catalyst comprising a CNT-mesoporous carbon composite comprising CNTs and mesoporous carbon, and metal catalyst particles uniformly supported on the CNT mesoporous carbon composite; and    (4) a fuel cell comprising a cathode, an anode and an electrolyte membrane interposed between the cathode and the anode, where either the cathode, the anode, or both the cathode and the anode comprises the supported catalyst.