The interaction of HCOOH with Rh foil has been investigated by various techniques at low and high temperatures with the primary motivation to determine the stability of formate species on unsupported Rh. The electron energy loss spectrum of Rh foil in the electronic range exhibited losses at 4.1, 5.4, 19.6, and 29.5 eV. Adsorption of HCOOH on Rh at 95 K produced new losses at 8.2, 11.3, and 14.2 eV. The intensities of these losses decreased with rise of sample temperature, and new losses developed at 9.5 (O(a)) and 13.2 eV (CO(a)). On the basis of the behaviour of the above losses, as well as that of the observed decomposition/desorption products of adsorbed HCOOH, it is concluded that (i) HCOOH is adsorbed dissociatively on Rh even at ~100 K, producing adsorbed H and formate species, (ii) the surface formate starts to decompose slightly below 200 K yielding H2, CO2, chemisorbed CO, and O, (iii) the decomposition goes to completion around 300 K, and (iv) the primary products of decomposition of formate species strongly interact with the Rh surface.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry