Relative Adsorption Strength Research Articles

Mutual displacement of NO, CO, and CO 2 adsorbed on NiO, shown by infrared spectra

Adsorption of two gases in alternative sequence does, or does not eliminate the infrared bands of the preadsorbed species, which are replaced in the first case by those of the second one. Qualitative inference on the relative adsorption strength of NO, CO, and CO 2 molecules on NiO is made. A peculiar shift of the CO 2 bands upon NO co-adsorption has been noticed.

Adsorption of hydrocarbons on acidic oxides as measured chromatographically

Gas-solid chromatography has been used to measure the relative strengths of adsorption of hydrocarbons on acidic oxide catalysts at temperatures up to 475 °C. Some of the results can be interpreted in terms of physical adsorption, but surface acidity of the adsorbent also influences the adsorption of aromatics. The binding between aromatics and acidic surfaces seems to be even more diffuse than in the π-bonds known in solution, in spite of the strong acids shown to be present on some of these surfaces by amine titration at room temperature. The heats of adsorption of hydrocarbons approximate the heats of liquifaction. Since much higher temperatures are necessary for desorption of pyridine and the effect of water vapor on adsorption is larger, chemisorption seems to be indicated for nitrogen bases.