Kinetics of the CH/CD isotope exchange reaction of formate (HCOO(a)/DCOO(a)) on Ni(110) with gaseous D2/H2 was investigated below the decomposition temperature (360 K) by infrared reflection absorption spectroscopy (IRAS). The apparent activation energies of HCOO(a) → DCOO (a) and DCOO(a) → HCOO-(a) reactions were derived as 52 ± 5 and 58 ± 5 kJ·mol-1, respectively. A half-order dependence of the reaction rate on hydrogen pressure was observed, suggesting that the rate-determining step was the reaction of the adsorbed formate with reversibly adsorbed hydrogen atom. The reaction of HCOO(a) with D2 was 2.1 ± 0.3 times faster than that of DCOO(a) with H2 at 300 K, and the origin of the isotope effect is discussed.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry