The effect of coadsorbed water on the stability, configuration and interconversion of formyl (HCO) and hydroxymethylidyne (COH) on platinum (1Â 1Â 1)

► DFT study of the C:H:O methanol electro-oxidation intermediate on Pt including water. ► The coadsorbed water affects stability and vibrational frequencies of COH and HCO. ► HCO, which is most stable on a bridge site, is the only stable form under water layer. ► HCO on a bridge site, under water layer show no CO vibrational frequency. ► The lack of CO frequency makes it hard to distinguish HCO from COH experimentally.