X-ray photoemission spectroscopy was used to study Pt-metal oxide aerogel catalysts that have been developed to respond to increased NOx emissions of lean-burn engines. Lean-burn engines, critical components of low and zero emission vehicles, produce much higher levels of engine-out NOx and current three-way catalytic converters are not sufficient to meet Clean Air Act standards. Platinum catalysts were formed by the reaction of modified Pt coordination compounds with selected transition-metal alkoxides through sot-gel techniques into aerogels. Photoemission measurements of the Pt 4f, Si 2p, Ti 2p, O 1 s, and C 1s core lines were used to evaluate the chemistry of the material after each processing step. Results indicate Pt-O bonding and reduced Pt disbursed in the aerogel. In addition, Si 2p, Ti 2p, and O 1s binding energies indicate an oxo-bridged network structure.