FORMATION OF ISOCYANATE ON CU(100) FROM THE OXIDATION OF CYANOGEN ANDFROM THE DECOMPOSITION OF ISOCYANIC ACID

Reflection adsorption infrared spectroscopy has been used to show that the same surface species forms on Cu(100) from the thermal decomposit ion of isocyanic acid (HNCO) and from the reaction of cyanogen (C2N2) with preadsorbed oxygen. This species is identified as isocyanate, NCO , linearly bonded to the surface through the nitrogen atom. It is char acterized by an intense band due to the asymmetric NCO stretch at 2201 cm(-1), a very weak band at 1321 cm(-1) due to the symmetric NCO stre tch, and a very weak band at 3448 cm(-1) due to the symmetric stretch plus asymmetric stretch combination band. Isotopic substitution with C -13, N-15, and O-18 supports the assignment. Isocyanate is stable on C u(100) up to 500 K. (C) 1997 Elsevier Science B.V.