Abstract

An <i>in situ</i> infrared cell capable of studying reactions over heterogeneous catalysts in the temperature range 77 to 773 K has been designed. In particular, the adsorption of formic acid on a model Cu/SiO<sub>2</sub> methanol synthesis catalyst was investigated. Exposure of a reduced copper surface to formic acid at 300 K resulted in the formation of both formic acid molecules, which were ligated to the copper catalyst, and chemisorbed bidentate copper formate species. Under temperature-programming conditions, the bidentate species displayed a maximum rate of desorption at 433 K, which correlates to a desorption activation energy of 120 kJ mol<sup>-1</sup>. In contrast, on the reoxidized catalyst, unidentate formate species were preferentially formed. These exhibited a maximum rate of desorption at a temperature of 408 K, and a desorption activation energy of 113 kJ mol<sup>-1</sup>. A mechanism was postulated to explain this behavior, and evidence was presented to show that useful kinetic data can be obtained for desorption from a catalyst in the form of a pressed disk.

PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription