Catalyst development for non-stationary redox application is still time consuming. A new method for high-throughput screening of catalysts under non-steady-state conditions is introduced enabling catalyst screening with >50 samples per day. The new method was applied to the oxidative dehydrogenation of ethylbenzene (ODEB) performed by alternately feeding ethylbenzene and oxygen. A highly selective mixed metal oxide catalyst (composition K2O (0.3 wt.%)/V2O5 (16 wt.%)/MgO) was found which converts ethylbenzene into styrene with an overall yield of 80.2% obtained by adding up both the wt.% ethylbenzene and the oxygen pulse. Selectivities in the ethylbenzene pulse amounted up to 98%. Mechanistic investigations reveal that the reaction does not proceed in a typical redox type mode. (C) 2003 Published by Elsevier Science B.V.