TY - JOUR
T1 - Insights into Reaction Kinetics in Confined Space
T2 - Real Time Observation of Water Formation under a Silica Cover
AU - Prieto, Mauricio J.
AU - Mullan, Thomas
AU - Schlutow, Mark
AU - Gottlob, Daniel M.
AU - Tǎnase, Liviu C.
AU - Menzel, Dietrich
AU - Sauer, Joachim
AU - Usvyat, Denis
AU - Schmidt, Thomas
AU - Freund, Hans Joachim
N1 - Publisher Copyright:
© 2021 The Authors. Published by American Chemical Society.
PY - 2021/6/16
Y1 - 2021/6/16
N2 - We offer a comprehensive approach to determine how physical confinement can affect the water formation reaction. By using free-standing crystalline SiO2 bilayer supported on Ru(0001) as a model system, we studied the water formation reaction under confinement in situ and in real time. Low-energy electron microscopy reveals that the reaction proceeds via the formation of reaction fronts propagating across the Ru(0001) surface. The Arrhenius analyses of the front velocity yield apparent activation energies (Eaapp) of 0.32 eV for the confined and 0.59 eV for the nonconfined reaction. DFT simulations indicate that the rate-determining step remains unchanged upon confinement, therefore ruling out the widely accepted transition state effect. Additionally, H2O accumulation cannot explain the change in Eaapp for the confined cases studied because its concentration remains low. Instead, numerical simulations of the proposed kinetic model suggest that the H2 adsorption process plays a decisive role in reproducing the Arrhenius plots.
AB - We offer a comprehensive approach to determine how physical confinement can affect the water formation reaction. By using free-standing crystalline SiO2 bilayer supported on Ru(0001) as a model system, we studied the water formation reaction under confinement in situ and in real time. Low-energy electron microscopy reveals that the reaction proceeds via the formation of reaction fronts propagating across the Ru(0001) surface. The Arrhenius analyses of the front velocity yield apparent activation energies (Eaapp) of 0.32 eV for the confined and 0.59 eV for the nonconfined reaction. DFT simulations indicate that the rate-determining step remains unchanged upon confinement, therefore ruling out the widely accepted transition state effect. Additionally, H2O accumulation cannot explain the change in Eaapp for the confined cases studied because its concentration remains low. Instead, numerical simulations of the proposed kinetic model suggest that the H2 adsorption process plays a decisive role in reproducing the Arrhenius plots.
UR - http://www.scopus.com/inward/record.url?scp=85108386782&partnerID=8YFLogxK
U2 - 10.1021/jacs.1c03197
DO - 10.1021/jacs.1c03197
M3 - Article
C2 - 34096299
AN - SCOPUS:85108386782
SN - 0002-7863
VL - 143
SP - 8780
EP - 8790
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 23
ER -