NOVELTY - A catalyst composition (C1) comprises 10-70 wt./wt.% of catalyst; 1-14 wt./wt.% of modifying agent; and 20-70 wt./wt.% of support material.    USE - As catalyst composition used for decomposition of lower hydrocarbons (e.g. methane and/or ethane) to produce carbon oxides free hydrogen and carbon nanotubes (claimed) used in fuel cells.    ADVANTAGE - The catalyst composition exhibits high stability of more than 70 hours at 750 degrees C. The Ni-Cu-Zn on alumina catalyst results in greater than 90% methane conversion (greater than 85% hydrogen yield) at 750 degrees C; and exhibits a life time of the catalyst of 70-75 hours when operated at 750 degrees C. The addition of small amounts of Cu as modifying agent (5 wt.%) increases the conversion of methane from 78 to 82% at the reaction temperature of 750 degrees C. Addition of both Cu and Zn modifying agent (5 wt.%) on Ni/Al2O3 catalyst increases the conversion and conferred highest methane conversion compared to other catalysts, where conversion is more than 86%.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) producing (P1) catalyst composition (C1) involving dissolving at least two salts selected from Ni, Co, Fe, Cu, and Zn in water to obtain solution; adding support material to the solution to obtain paste; drying the paste at 120 degrees C for 1-48 hours to obtain dried paste; calcining the dried paste at 400-600 degrees C for 1-6 hours to obtain precursor catalyst; and reducing the precursor catalyst by hydrogen and in the presence of nitrogen at 380-450 degrees C for 1-6 hours to obtain catalyst composition (C1);    (2) producing (P2) catalyst composition (C1) involving dissolving nitrate salts of Ni, Cu, and Zn in water to obtain solution; adding alumina to the solution to obtain paste; drying the paste at 120 degrees C for 24 hours to obtain a dried paste; calcining the dried paste at 550 degrees C for 6 hours to obtain a precursor catalyst; and reducing the precursor catalyst by hydrogen in the presence of nitrogen at 450 degrees C for 6 hours to obtain catalyst composition (C1);    (3) producing (P3) carbon oxides free hydrogen and carbon nanotubes involving placing catalyst composition (C1) in reactor; passing flow of lower hydrocarbon in the presence of optionally used carrier gas in the range of 10-100 ml/minutes over the catalyst composition (C1) at 550-800 degrees C at atmospheric pressure; and recovering the carbon oxide free stream and carbon nanotubes, where the stream comprises hydrogen, unreacted lower hydrocarbon and the optionally used carrier gas;    (4) producing (P4) carbon oxides free hydrogen and carbon nanotubes, involving placing catalyst composition (C1) in fixed bed tubular reactor; passing flow of methane in the presence of optionally used carrier gas at the rate of 20 ml/minute over the catalyst composition at a temperature of 750 degrees C at atmospheric pressure; and recovering the carbon oxide free stream and carbon nanotubes where the stream comprises hydrogen, unreacted methane and the optionally used carrier gas.