In the present study, the surface catalytic reaction in a microchannel with nonreactive hydrogen-air flow is investigated. Here, the microchannel wall is coated with a catalyst. A solution to the catalytic microchannel flow is gained by applying an iterative method to solve the energy, mole fraction, and catalytic reaction equations. To validate the model, the results of fuel conversion are compared with the results of experimental studies available in the literature, and a good agreement between them is achieved. Moreover, the results show that increasing the hydraulic diameter of the microchannel decreases normalized temperature of the mixture and catalyst heat transfer. Steeper variations are observed in the case of d h ∕L < 0.2. Furthermore, when the wall-to-inlet-temperature ratio is smaller than 2.5, the fuel conversion is very small; and for T W ∕T i > 3.5, the fuel is fully converted.rate constant of catalytic reaction, m · s −1 L = channel length, m M = molecular weight of species _ m = mass flow rate, kg · s −1 Nu = Nusselt number; hd h ∕k P = static pressure, atm Pe = Péclet number; υd h ∕α Pr = Prandtl number; υ∕α Pe m = mass Péclet number; υd h ∕D AB p = wetted perimeter of microchannel, m Q = catalyst heat transfer to flow, W Q = normalized catalyst heat transfer R = gas constant, J · kg −1 K −1 Re = Reynolds number; vd h ∕υ S = ratio of convection mass transfer to reaction rate Sc = Schmidt number; υ∕D AB Sh = Sherwood number; h m d h ∕D AB S = normalized sensitivity analysis parameter T = temperature, K v = flow velocity, m · s −1 W C = rate of fuel consumption, mole · m −2 s −1 X = axial location, m X = normalized axial location Y = bulk mole fraction of fuel Y = mole fraction of fuel θ = normalized temperature μ = dynamic viscosity, ns · m −1 υ = diffusion volumes of samples; Eq. (11) ρ = density, kg · m −3 Φ = model response parameter Subscripts c = conversion, catalytic reaction i = inlet, samples m = mass S = surface W = wall 0 = nominal value