CH bond weakening of cyclohexane on Ni(1 1 1) by coadsorbed CO

The effect of coadsorbed CO on the activation of the CH bond of cyclohexane adsorbed on Ni(1 1 1) was investigated by temperature programmed desorption and Fourier transform infrared reflection absorption spectroscopy. Coadsorption of CO caused an upward shift of desorption temperature of cyclohexane and a downward shift of vibrational frequency of the CH stretching. These results indicate that the CH bonds, which point toward the metal surface, are weakened by coadsorbed CO.