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Computational Study on M1/POM Single-Atom Catalysts (M = Cu, Zn, Ag, and Au; POM = [PW12O40]3–): Metal–Support Interactions and Catalytic Cycle for Alkene Epoxidation
- Source :
- Inorganic Chemistry. 56:10496-10504
- Publication Year :
- 2017
- Publisher :
- American Chemical Society (ACS), 2017.
-
Abstract
- Geometrical structures, metal-support interactions, and infrared (IR) spectroscopy of a series of M1/POM (M = Cu, Zn, Ag, and Au; POM = [PW12O40]3-) single-atom catalysts (SACs), and catalytic cycle for alkene epoxidation catalyzed by M1/POM SACs were studied using density functional theory (DFT) calculations. The calculations demonstrate that the most probable anchoring sties for the isolated single atoms studied here in the M1/POM SACs are the fourfold hollow sites on the surface of POM support. The bonding interaction between single metal atom and surface of POM support comes from the molecular orbitals with a mixture of d atomic orbital of metal and 2p group orbital of surface oxygen atoms of POM cage. The calculated adsorption energy of isolated metal atoms in these M1/POM SACs indicates that the early transition metals (Cu and Zn) have high thermal stability. The DFT-derived IR spectra show that the four characteristic peaks of free Keggin-type POM structure split into six because of introduction of isolated metal atom. Compared with other metal atoms, the Zn1/POM SAC has the high reactivity for activity of dioxygen molecule, because the dioxygen moiety in Zn1/POM SAC displays O2-· radical feature with [POM4-·Zn2+O2-·]3- configuration. Finally, a catalytic cycle for ethylene epoxidation by O2 catalyzed by Zn1/POM SAC was proposed based on our DFT calculations. Supported noble-metal SACs are among the most important catalysts currently. However, noble metals are expensive and of limited supply. Development of non-noble-metal SACs is of essential importance. Therefore, the reported Zn1/POM SAC would be very useful to guide the search for SACs into non-noble metals.
- Subjects :
- 010405 organic chemistry
Chemistry
Stereochemistry
Infrared spectroscopy
010402 general chemistry
01 natural sciences
0104 chemical sciences
Catalysis
Inorganic Chemistry
Metal
Crystallography
Transition metal
Catalytic cycle
visual_art
visual_art.visual_art_medium
Molecule
Density functional theory
Molecular orbital
Physical and Theoretical Chemistry
Subjects
Details
- ISSN :
- 1520510X and 00201669
- Volume :
- 56
- Database :
- OpenAIRE
- Journal :
- Inorganic Chemistry
- Accession number :
- edsair.doi...........c62b49accfe6626d250a9b155d2b2cd8