Cu(0 0 1)-bound isocyanate species (NCO (a )) have been prepared with two distinct methods. Isocyanic acid (HNCO) exposures at room temperature resulted in adsorbed NCO ( a) alone. The exposure of Cu(0 0 1) to cyanogen (C 2N 2) and O 2 leads to surfaces displaying co-adsorbed oxygen (O (a)), cyanide (CN (a)), and NCO (a ) species. O 2 exposure of submonolayer NCO/Cu(0 0 1), followed by brief annealing at 473 K, initiated NCO (a ) oxidation, giving rise to CO 2(g) desorption and a surface-bound atomic N (a) species. CO 2(g) evolution was observed over a wide range of initial O (a) coverages. In contrast, comparable thermal treatments of CN + O + NCO/Cu(0 0 1) samples, at 473 K, yield both CO (g) and CO 2(g). Both TPRD and XPS studies of pre- and post-annealed surfaces indicated the two gaseous products. The co-adsorption of CN (a) promotes the dissociation of NCO (a) into CO (g) and N (a), and dissociation can become the dominant means for NCO (a) removal.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry