Enhanced production of singlet oxygen, O-2(a(1)Delta g), was observed by reaction of O-2/He discharge effluents on an iodine oxide film surface in a microwave discharge-flow reactor at 320 K. We observed a two-fold increase in the O-2(a) yields over discharge-generated amounts for non-catalytic conditions. The iodine oxide surface appears to catalyze the heterogeneous reaction to form O-2(a) with high collision efficiency. The observed catalytic effect could significantly benefit the development of electrically driven oxygen iodine laser systems, and may also have implications for the chemistry of atmospheric iodine oxide aerosol. (C) 2008 Elsevier B.V. All rights reserved.