TY - JOUR
T1 - Stability investigation of a high number density Pt1/Fe2O3 single-atom catalyst under different gas environments by HAADF-STEM
AU - Duan, Sibin
AU - Wang, Rongming
AU - Liu, Jingyue
N1 - Funding Information:
This research was supported by the National Science Foundation under CHE-1465057, the National Natural Science Foundation of China under 11674023 and 51331002, the Beijing Municipal Science and Technology Project (No. Z1711100002217074), and the Fundamental Research Funds for the Central Universities under FRF-TP-16-067A1. J L acknowledges the start-up fund of the College of Liberal Arts and Sciences of Arizona State University. We acknowledge the use of the STEM at the John M Cowley Center for High Resolution Microscopy at Arizona State University.
Publisher Copyright:
© 2018 IOP Publishing Ltd.
PY - 2018/3/22
Y1 - 2018/3/22
N2 - Catalysis by supported single metal atoms has demonstrated tremendous potential for practical applications due to their unique catalytic properties. Unless they are strongly anchored to the support surfaces, supported single atoms, however, are thermodynamically unstable, which poses a major obstacle for broad applications of single-atom catalysts (SACs). In order to develop strategies to improve the stability of SACs, we need to understand the intrinsic nature of the sintering processes of supported single metal atoms, especially under various gas environments that are relevant to important catalytic reactions. We report on the synthesis of high number density Pt1/Fe2O3 SACs using a facial strong adsorption method and the study of the mobility of these supported Pt single atoms at 250 °C under various gas environments that are relevant to CO oxidation, water-gas shift, and hydrogenation reactions. Under the oxidative gas environment, Fe2O3 supported Pt single atoms are stable even at high temperatures. The presence of either CO or H2 molecules in the gas environment, however, facilitates the movement of the Pt atoms. The strong interaction between CO and Pt weakens the binding between the Pt atoms and the support, facilitating the movement of the Pt single atoms. The dissociation of H2 molecules on the Pt atoms and their subsequent interaction with the oxygen species of the support surfaces dislodge the surface oxygen anchored Pt atoms, resulting in the formation of Pt clusters. The addition of H2O molecules to the CO or H2 significantly accelerates the sintering of the Fe2O3 supported Pt single atoms. An anchoring-site determined sintering mechanism is further proposed, which is related to the metal-support interaction.
AB - Catalysis by supported single metal atoms has demonstrated tremendous potential for practical applications due to their unique catalytic properties. Unless they are strongly anchored to the support surfaces, supported single atoms, however, are thermodynamically unstable, which poses a major obstacle for broad applications of single-atom catalysts (SACs). In order to develop strategies to improve the stability of SACs, we need to understand the intrinsic nature of the sintering processes of supported single metal atoms, especially under various gas environments that are relevant to important catalytic reactions. We report on the synthesis of high number density Pt1/Fe2O3 SACs using a facial strong adsorption method and the study of the mobility of these supported Pt single atoms at 250 °C under various gas environments that are relevant to CO oxidation, water-gas shift, and hydrogenation reactions. Under the oxidative gas environment, Fe2O3 supported Pt single atoms are stable even at high temperatures. The presence of either CO or H2 molecules in the gas environment, however, facilitates the movement of the Pt atoms. The strong interaction between CO and Pt weakens the binding between the Pt atoms and the support, facilitating the movement of the Pt single atoms. The dissociation of H2 molecules on the Pt atoms and their subsequent interaction with the oxygen species of the support surfaces dislodge the surface oxygen anchored Pt atoms, resulting in the formation of Pt clusters. The addition of H2O molecules to the CO or H2 significantly accelerates the sintering of the Fe2O3 supported Pt single atoms. An anchoring-site determined sintering mechanism is further proposed, which is related to the metal-support interaction.
KW - catalyst stability
KW - heterogeneous catalysis
KW - metalsupport interaction
KW - single-atom catalyst
KW - sintering
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U2 - 10.1088/1361-6528/aab1d2
DO - 10.1088/1361-6528/aab1d2
M3 - Article
C2 - 29473830
AN - SCOPUS:85044820105
SN - 0957-4484
VL - 29
JO - Nanotechnology
JF - Nanotechnology
IS - 20
M1 - 204002
ER -