Comparative studies of methanol decomposition on carbide-modified V(1 1 0) and Ti(0 0 0 1)

The reaction pathways of methanol on V(1 1 0), carbide-modified V(1 1 0), Ti(0 0 0 1), and carbide-modified Ti(0 0 0 1) have been studied using high-resolution electron energy loss spectroscopy (HREELS), Auger electron spectroscopy (AES), and temperature-programmed desorption (TPD). On V(1 1 0) and C/V(1 1 0), methanol undergoes complete dissociative adsorption producing a methoxy intermediate for exposures less than 2 L at 100 K. On Ti(0 0 0 1) and C/Ti(0 0 0 1), methanol dissociates to produce methoxy at exposures of 3 L at 100 K. The combination of TPD and AES reveals that the number of methoxy per surface metal atom is 0.13 on C/V(1 1 0) and 0.41 on C/Ti(0 0 0 1) at 100 K. All methoxy species undergo further decomposition on C/V(1 1 0) at higher temperatures. However, a significant fraction (∼39%) of methoxy species undergo recombinatory reaction to produce gas-phase methanol on C/Ti(0 0 0 1). The reaction pathways on the C/V(1 1 0) and C/Ti(0 0 0 1) surfaces are compared with previous studies of methanol on other carbide-modified surfaces, as well as on single crystal VC and TiC surfaces.