TY - JOUR
T1 - Mechanistic study of oxygen reduction reaction on a Pd/CeO2-ZrO2 catalyst
AU - Min You, Hyo
AU - Nagasawa, Tsuyoshi
AU - Woo Lee, Jae
AU - Kwon, Hyunguk
AU - Kim, Kyeounghak
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2024/3/1
Y1 - 2024/3/1
N2 - Three-way catalysts (TWCs) are widely used to convert the exhaust gases produced by internal combustion engines, including hydrocarbons, CO, and NOx, into harmless gases such as CO2, N2, and H2O. TWCs mainly consist of a metal catalyst, catalyst support, and ceramic substrate, and their performance is known to be closely related to the oxygen storage capacity (OSC) of the ceramic substrates. However, oxygen storage is a complex multi-step process that is not yet fully understood. In this study, we visualized oxygen storage at the Pd/CeO2–ZrO2 (CZ) interface in the practical operating temperature range of TWCs using oxygen isotope quench techniques and elucidated the detailed reaction mechanism using density functional theory calculations. Pd supported on CZ promotes the incorporation of oxygen into the CZ surface. In addition, our investigation of the transport behavior of the incorporated oxygen in the bulk regime reveals that the bond strength between oxygen and surrounding atoms is weakened by Zr doping, resulting in more facile oxygen vacancy formation and oxygen migration. Our results provide useful insights that will guide the future design of highly active TWCs.
AB - Three-way catalysts (TWCs) are widely used to convert the exhaust gases produced by internal combustion engines, including hydrocarbons, CO, and NOx, into harmless gases such as CO2, N2, and H2O. TWCs mainly consist of a metal catalyst, catalyst support, and ceramic substrate, and their performance is known to be closely related to the oxygen storage capacity (OSC) of the ceramic substrates. However, oxygen storage is a complex multi-step process that is not yet fully understood. In this study, we visualized oxygen storage at the Pd/CeO2–ZrO2 (CZ) interface in the practical operating temperature range of TWCs using oxygen isotope quench techniques and elucidated the detailed reaction mechanism using density functional theory calculations. Pd supported on CZ promotes the incorporation of oxygen into the CZ surface. In addition, our investigation of the transport behavior of the incorporated oxygen in the bulk regime reveals that the bond strength between oxygen and surrounding atoms is weakened by Zr doping, resulting in more facile oxygen vacancy formation and oxygen migration. Our results provide useful insights that will guide the future design of highly active TWCs.
KW - Density functional theory
KW - Oxygen isotope labeling
KW - Oxygen reduction reaction
KW - Reaction mechanism
KW - Three-way catalyst
UR - https://www.scopus.com/pages/publications/85179009047
U2 - 10.1016/j.apsusc.2023.159045
DO - 10.1016/j.apsusc.2023.159045
M3 - Article
AN - SCOPUS:85179009047
SN - 0169-4332
VL - 648
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 159045
ER -