Surface reactivity of NiO: Interaction with methanol

The interaction between methanol and a NiO powder sample was studied. The obtained NiO, was characterized by means of X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, X-ray diffraction (XRD), and thermal analysis. Chemisorption experiments at atmospheric pressure were studied by means of diffuse reflectance infrared spectroscopy, whereas those carried out under high vacuum (HV) conditions were followed by means of XPS and quadrupolar mass spectrometry (QMS). Methanol interacts mainly molecularly with the NiO powder surface whereas dissociative chemisorption is more evident at higher temperatures. The formation of CO2 and of formate species is evident at T greater than or equal to 323 and 423 K, respectively. Under HV conditions formaldehyde forms at higher temperatures.