Mechanism of the Catalytic Synthesis of Water on Silver
, E-ISSN: 1364-551X
Dokuchits Eugene V.
Khasin Alexander V.
Khassin Alexander A.
Novosibirsk State University, 630090 Novosibirsk, Russian Federation
G. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
630090 Novosibirsk, Russian Federation
The Ministry of Education and Science of the Russian Federation
Early studies1–3 have demonstrated that the test reaction proceeds by the mechanism consisting of two consecutive steps: the chemisorption of oxygen and the interaction of gaseous hydrogen with adsorbed oxygen. However, further studies have revealed that the reaction has a more complicated mechanism and occurs via the intermediate formation of surface hydroxyl groups by the three-step mechanism:
O2 = 2Oads, (1)
H2 + 2Oads = 2OHads, (2)
H2 + 2OHads = 2H2O. (3)
The kinetics and mechanism of steps (2) and (3) are unknown. The adsorption of oxygen (1) and step (2) proceed more rapidly, as compared to step (3).6 In the steady state, the preponderant fraction of adsorbed oxygen will reside most likely on the silver surface as the OHads groups. In this case, the rate of hydrogen interaction with the silver surface, which has a stationary composition, will be the rate of step (3) in the test reaction mechanism.
The aim of this work was to elucidate the regularities of this step .