A study of CO formation for steam reforming of methanol on a commercial CuO/ZnO/Al2O3 catalyst has been performed in the temperature range 230-300degreesC and at atmospheric pressure. The reaction schemes considered in this work are the methanol-steam reforming (SR) reaction and the reverse water gas-shift (rWGS) reaction. Power rate laws for the SR and reverse WGS reactions were used in a refinement of rate equations to the experiment data. For the temperature range studied the reaction order of methanol was determined under differential conversion (less than 10%) and was found to be 0.2. The integral method (partial pressure of the reactants and products measured as a function of contact time) was then applied to determine the reaction rate constants, activation energies, and pre-exponential factors for both reactions. The experimental results of CO partial pressure as a function of contact time at different reaction temperatures show very clearly that CO was formed as a consecutive product. The implications of the reaction scheme, in particular with respect to the production of CO as a secondary product, are discussed in the framework of on-board production of H-2 for fuel cell applications in automobiles. Potential chemical engineering solutions for minimizing CO production are outlined. (C) 2003 Elsevier B.V. All rights reserved.