Adsorption of carbon dioxide on polycrystalline copper

Abstract

The adsorption of CO₂ on clean non-porous polycrystalline copper films has been studied at temperatures between 77 and 298 K by volumetric and surface potential measurements. No evidence has been found for any interaction other than simple physical adsorption following exposures of up to 800 Pa at 298 K or to 1.7 Pa at 113 K. Monolayer formation at 113 K gave a surface potential change of 0.28 V, compared to 0.55 V for Xe, suggesting that CO₂ molecules are adsorbed with the molecular axis parallel to the metal surface, and the effective molecular area was ca. 0.16 nm². Preadsorbed hydrogen reduced the CO₂ surface potential change to zero but did not affect the adsorption isotherm. At 298 K CO₂ was not adsorbed, nor did its presence in the gas affect the equilibrium adsorption of hydrogen.