A versatile photoionization detection (PID) system has been developed to rapidly screen libraries of catalytic materials. The PID approach involves the use of an appropriately selected dc discharge lamp to obtain monoenergetic photons, which are then used to photoionize gaseous molecules whose ionization potentials are lower than the photon energy. The suitability of the PID as a rapid screening tool has been demonstrated using oxidative dehydrogenation of ethane and propane as example reactions. Two 66 member ternary libraries of V-Mo-Li and V-Mo-Rb on gamma-Al2O3 were tested for ethylene and propylene formation using the 10.6 eV photons from a Kr discharge lamp. The PID screening allowed the determination of 6% V, 3% Mo and 1% Li as the optimal catalyst formulation with regard to maximum alkene production for both reactions in a matter of hours. (C) 2003 Elsevier Science B.V. All rights reserved.