NOVELTY - A supported catalyst comprises a mesoporous carbon molecular sieve having an average primary particle size of less than 500 mum, an average mesopore size of 3 mum-6 nm, and a surface area of 500-2000 m2/g; and catalytic metal particles dispersed in and supported on the mesoporous carbon molecular sieve.    USE - For a fuel cell.    ADVANTAGE - The supported catalyst displays improved catalytic activity.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a mesoporous carbon molecular sieve for a support of a supported catalyst;    (2) a method of controlling the primary particle size of a mesoporous silica, comprising reacting sodium hydroxide (NaOH) with silicon dioxide (SiO2) in a water-based reaction medium to form sodium silicate, reacting the sodium silicate, a poly(ethyleneglycol)block-poly(propyleneglycol)-block-poly(ethyleneglycol), and an acetic acid in a water-based reaction medium to obtain precipitates, and drying and calcining the precipitates to obtain the mesoporous silica, where the Na:Si atomic ratio of the formed sodium silicate is controlled by controlling the amount of each of NaOH and SiO2 when forming the sodium silicate and the average particle size of the formed mesoporous silica is reduced by increasing the Na:Si atomic ratio;    (3) a method of preparing a mesoporous silica molecular sieve having an average primary particle size of 250-700 nm, comprising reacting sodium silicate with Na:Si atomic ratio of 1.5-2.5, a poly(ethyleneglycol)-block-poly(propyleneglycol)-block-poly(ethyleneglycol), and an acetic acid to obtain precipitates; and drying and calcining the precipitates;    (4) a method of preparing a mesoporous carbon molecular sieve, comprising filling a carbon precursor in pores of a template comprising a mesoporous silica having an average primary particle size of 250-700 nm, thermally decomposing the carbon precursor by heating the template having the carbon precursor impregnated under a non-oxidizing atmosphere to form a carbon structure in the pores of the template, and removing the template using a silica-soluble solution, thus isolating the carbon structure; and    (5) a fuel cell comprising a cathode, an anode, and an electrolyte membrane interposed between the cathode and the anode, where the cathode and/or the anode contains the supported catalyst.