Abstract
Catalytic water oxidation has been investigated using five iridium complexes as precatalysts and NaIO4 as an oxidant at various pH conditions. An increase in the activity of all complexes was observed with increasing pH. A detailed analysis of spectroscopic data together with O 2-evolution experiments using Cp*Ir(6,6′-dihydroxy-2, 2′-bipyridine)(OH2)2+ as a precatalyst indicate that the high catalytic activity is closely connected with transient species (A) that exhibits an absorption band at λmax 590 nm. The formation of this active form is strongly dependent on reaction conditions, and the species was distinctly observed using a small excess of periodate. However, another species absorbing at 600 nm (B), which seems to be a less active catalyst, was also observed and was more prominent at high oxidant concentration. Dynamic light scattering analysis and transmission electron microscopy have identified species B as 120 nm nanoparticles. The ultrafiltration method has revealed that species A can be attributed to particles with size in the range of 0.5-2 nm, possibly small IrOx clusters similar to those described previously by Harriman and co-workers (J. Phys. Chem., 1991, 95, 616-621).
| Original language | English |
|---|---|
| Pages (from-to) | 11976-11987 |
| Number of pages | 12 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 16 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - Jun 28 2014 |
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- Physical and Theoretical Chemistry
- Physics and Astronomy(all)
- Medicine(all)
Cite this
Efficient water oxidation with organometallic iridium complexes as precatalysts. / Lewandowska-Andralojc, Anna; Polyansky, Dmitry; Wang, Chiu Hui; Wang, Wan Hui; Himeda, Yuichiro; Fujita, Etsuko.
In: Physical Chemistry Chemical Physics, Vol. 16, No. 24, 28.06.2014, p. 11976-11987.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Efficient water oxidation with organometallic iridium complexes as precatalysts
AU - Lewandowska-Andralojc, Anna
AU - Polyansky, Dmitry
AU - Wang, Chiu Hui
AU - Wang, Wan Hui
AU - Himeda, Yuichiro
AU - Fujita, Etsuko
PY - 2014/6/28
Y1 - 2014/6/28
N2 - Catalytic water oxidation has been investigated using five iridium complexes as precatalysts and NaIO4 as an oxidant at various pH conditions. An increase in the activity of all complexes was observed with increasing pH. A detailed analysis of spectroscopic data together with O 2-evolution experiments using Cp*Ir(6,6′-dihydroxy-2, 2′-bipyridine)(OH2)2+ as a precatalyst indicate that the high catalytic activity is closely connected with transient species (A) that exhibits an absorption band at λmax 590 nm. The formation of this active form is strongly dependent on reaction conditions, and the species was distinctly observed using a small excess of periodate. However, another species absorbing at 600 nm (B), which seems to be a less active catalyst, was also observed and was more prominent at high oxidant concentration. Dynamic light scattering analysis and transmission electron microscopy have identified species B as 120 nm nanoparticles. The ultrafiltration method has revealed that species A can be attributed to particles with size in the range of 0.5-2 nm, possibly small IrOx clusters similar to those described previously by Harriman and co-workers (J. Phys. Chem., 1991, 95, 616-621).
AB - Catalytic water oxidation has been investigated using five iridium complexes as precatalysts and NaIO4 as an oxidant at various pH conditions. An increase in the activity of all complexes was observed with increasing pH. A detailed analysis of spectroscopic data together with O 2-evolution experiments using Cp*Ir(6,6′-dihydroxy-2, 2′-bipyridine)(OH2)2+ as a precatalyst indicate that the high catalytic activity is closely connected with transient species (A) that exhibits an absorption band at λmax 590 nm. The formation of this active form is strongly dependent on reaction conditions, and the species was distinctly observed using a small excess of periodate. However, another species absorbing at 600 nm (B), which seems to be a less active catalyst, was also observed and was more prominent at high oxidant concentration. Dynamic light scattering analysis and transmission electron microscopy have identified species B as 120 nm nanoparticles. The ultrafiltration method has revealed that species A can be attributed to particles with size in the range of 0.5-2 nm, possibly small IrOx clusters similar to those described previously by Harriman and co-workers (J. Phys. Chem., 1991, 95, 616-621).
UR - http://www.scopus.com/inward/record.url?scp=84901798959&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901798959&partnerID=8YFLogxK
U2 - 10.1039/c3cp55101f
DO - 10.1039/c3cp55101f
M3 - Article
C2 - 24549266
AN - SCOPUS:84901798959
VL - 16
SP - 11976
EP - 11987
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 24
ER -