uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 136) Show all publications
Liu, T., Guo, M., Orthaber, A., Lomoth, R., Lundberg, M., Ott, S. & Hammarström, L. (2018). Accelerating proton-coupled electron transfer of metal hydrides in catalyst model reactions. Nature Chemistry, 10(8), 881-887
Open this publication in new window or tab >>Accelerating proton-coupled electron transfer of metal hydrides in catalyst model reactions
Show others...
2018 (English)In: Nature Chemistry, ISSN 1755-4330, E-ISSN 1755-4349, Vol. 10, no 8, p. 881-887Article in journal (Refereed) Published
Abstract [en]

Metal hydrides are key intermediates in catalytic proton reduction and dihydrogen oxidation. There is currently much interest in appending proton relays near the metal centre to accelerate catalysis by proton-coupled electron transfer (PCET). However, the elementary PCET steps and the role of the proton relays are still poorly understood, and direct kinetic studies of these processes are scarce. Here, we report a series of tungsten hydride complexes as proxy catalysts, with covalently attached pyridyl groups as proton acceptors. The rate of their PCET reaction with external oxidants is increased by several orders of magnitude compared to that of the analogous systems with external pyridine on account of facilitated proton transfer. Moreover, the mechanism of the PCET reaction is altered by the appended bases. A unique feature is that the reaction can be tuned to follow three distinct PCET mechanisms-electron-first, proton-first or a concerted reaction-with very different sensitivities to oxidant and base strength. Such knowledge is crucial for rational improvements of solar fuel catalysts.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-357209 (URN)10.1038/s41557-018-0076-x (DOI)000439420400015 ()30013192 (PubMedID)
Funder
Swedish Research Council, 2016-04271Knut and Alice Wallenberg Foundation, 2011.0067
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2019-01-04Bibliographically approved
Hammarström, L., Abdellah, M. & Gilbert Gatty, M. (2018). Capturing intermediates of molecular catalyst/semiconductor systems by transient mid-IR spectroscopy.. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, USA.. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Capturing intermediates of molecular catalyst/semiconductor systems by transient mid-IR spectroscopy.
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Washington, D.C.: American Chemical Society (ACS), 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-368926 (URN)000435539902256 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, USA.
Note

Meeting Abstract: 109

Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
Huang, J., Gilbert Gatty, M., Xu, B., Pati, P. B., Etman, A. S., Tian, L., . . . Tian, H. (2018). Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2 reduction. Dalton Transactions, 47(31), 10775-10783
Open this publication in new window or tab >>Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2 reduction
Show others...
2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 31, p. 10775-10783Article in journal (Refereed) Published
Abstract [en]

Covalently linking photosensitizers and catalysts in an inorganic-organic hybrid photocatalytic system is beneficial for efficient electron transfer between these components. However, general and straightforward methods to covalently attach molecular catalysts on the surface of inorganic semiconductors are rare. In this work, a classic rhenium bipyridine complex (Re catalyst) has been successfully covalently linked to the low toxicity CuInS2 quantum dots (QDs) by click reaction for photocatalytic CO2 reduction. Covalent bonding between the CuInS2 QDs and the Re catalyst in the QD-Re hybrid system is confirmed by UV-visible absorption spectroscopy, Fourier-transform infrared spectroscopy and energy-dispersive X-ray measurements. Time-correlated single photon counting and ultrafast time-resolved infrared spectroscopy provide evidence for rapid photo-induced electron transfer from the QDs to the Re catalyst. Upon photo-excitation of the QDs, the singly reduced Re catalyst is formed within 300 fs. Notably, the amount of reduced Re in the linked hybrid system is more than that in a sample where the QDs and the Re catalyst are simply mixed, suggesting that the covalent linkage between the CuInS2 QDs and the Re catalyst indeed facilitates electron transfer from the QDs to the Re catalyst. Such an ultrafast electron transfer in the covalently linked CuInS2 QD-Re hybrid system leads to enhanced photocatalytic activity for CO2 reduction, as compared to the conventional mixture of the QDs and the Re catalyst.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-363108 (URN)10.1039/c8dt01631c (DOI)000441151700051 ()30019727 (PubMedID)
Funder
Swedish Research CouncilSwedish Energy AgencyGöran Gustafsson Foundation for promotion of scientific research at Uppala University and Royal Institute of TechnologyStiftelsen Olle Engkvist Byggmästare
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2018-10-15Bibliographically approved
Gilbert Gatty, M., Pullen, S., Sheibani, E., Tian, H., Ott, S. & Hammarström, L. (2018). Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy. Chemical Science, 9(22), 4983-4991
Open this publication in new window or tab >>Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy
Show others...
2018 (English)In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 22, p. 4983-4991Article in journal (Refereed) Published
Abstract [en]

Co-sensitization of molecular dyes and catalysts on semiconductor surfaces is a promising strategy to build photoelectrodes for solar fuel production. In such a photoelectrode, understanding the charge transfer reactions between the molecular dye, catalyst and semiconductor material is key to guide further improvement of their photocatalytic performance. Herein, femtosecond mid-infrared transient absorption spectroscopy is used, for the first time, to probe charge transfer reactions leading to catalyst reduction on co-sensitized nickel oxide (NiO) photocathodes. The NiO films were co-sensitized with a molecular dye and a proton reducing catalyst from the family of [FeFe](bdt)(CO)(6) (bdt = benzene-1,2-dithiolate) complexes. Two dyes were used: an organic push-pull dye denoted E2 with a triarylamine-oligothiophene-dicyanovinyl structure and a coumarin 343 dye. Upon photo-excitation of the dye, a clear spectroscopic signature of the reduced catalyst is observed a few picoseconds after excitation in all co-sensitized NiO films. However, kinetic analysis of the transient absorption signals of the dye and reduced catalyst reveal important mechanistic differences in the first reduction of the catalyst depending on the co-sensitized molecular dye (E2 or C343). While catalyst reduction is preceded by hole injection in NiO in C343-sensitized NiO films, the singly reduced catalyst is formed by direct electron transfer from the excited dye E2* to the catalyst in E2-sensitized NiO films. This change in mechanism also impacts the lifetime of the reduced catalyst, which is only ca. 50 ps in E2-sensitized NiO films but is >5 ns in C343-sensitized NiO films. Finally, the implication of this mechanistic study for the development of better co-sensitized photocathodes is discussed.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-358380 (URN)10.1039/c8sc00990b (DOI)000434693300008 ()
Funder
Swedish Energy Agency, 11645-5
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-08-29Bibliographically approved
Tang, Y., Cao, X., Honarfar, A., Abdellah, M., Chen, C., Avila, J., . . . Chi, Q. (2018). Inorganic Ions Assisted the Anisotropic Growth of CsPbCl3 Nanowires with Surface Passivation Effect. ACS Applied Materials and Interfaces, 10(35), 29574-29582
Open this publication in new window or tab >>Inorganic Ions Assisted the Anisotropic Growth of CsPbCl3 Nanowires with Surface Passivation Effect
Show others...
2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 35, p. 29574-29582Article in journal (Refereed) Published
Abstract [en]

All-inorganic halide perovskite nanowires (NWs) exhibit improved thermal and hydrolysis stability and could thus play a vital role in nanoscale optoelectronics. Among them, blue-light-based devices are extremely limited because of the lack of a facile method to obtain high-purity CsPbCl3 NWs. Herein, we report a direct and facile method for the synthesis of CsPbCl3 NWs assisted by inorganic ions that served both as a morphology controlling agent for the anisotropic growth of nanomaterials and a surface passivation species modulating the surface of nanomaterials. This new approach allows us to obtain high-purity and size-uniform NWs as long as 500 nm in length and 20 nm in diameter with high reproducibility. X-ray photoelectron spectroscopy and ultrafast spectroscopic measurements confirmed that a reduced band gap caused by the surface species of NWs relative to nanocubes (NCs) was achieved at the photon energy of 160 eV because of the hybrid surface passivation contributed by adsorbed inorganic ions. The resulting NWs demonstrate significantly enhanced photoelectrochemical performances, 3.5-fold increase in the photocurrent generation, and notably improved stability compared to their NC counterparts. Our results suggest that the newly designed NWs could be a promising material for the development of nanoscale optoelectronic devices.

Keywords
inorganic halide perovskite, CsPbCl3 nanowires, surface passivation, photoelectrochemical cell, electron and hole injection, ultrafast spectroscopy
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-365656 (URN)10.1021/acsami.8b09113 (DOI)000444355700038 ()30088920 (PubMedID)
Funder
Swedish Research Council, 2017-05337
Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2018-11-16Bibliographically approved
Tyburski, R., Föhlinger, J. & Hammarström, L. (2018). Light Driven Electron Transfer in Methylbipyridine/Phenol Complexes Is Not Proton Coupled. Paper presented at 18th Meeting on Time-Resolved Vibrational Spectroscopy (TRVS), 2017, Cambridge, ENGLAND. Journal of Physical Chemistry A, 122(18), 4425-4429
Open this publication in new window or tab >>Light Driven Electron Transfer in Methylbipyridine/Phenol Complexes Is Not Proton Coupled
2018 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 122, no 18, p. 4425-4429Article in journal (Refereed) Published
Abstract [en]

The pursuit of systems that undergo optical electron proton transfer (photo-EPT) is very attractive, due to the wealth of information contained in the absorption spectra of such complexes. However, separating photo-EPT transitions from conventional charge transfer states remains a major challenge. In this study, we show that optical charge transfer in a complex between 4-methoxyphenol and N-methyl-4,4'-bipyridyl, previously assigned to occur through photo-EPT involving a hydrogen bond between the reactants (GagliardiC. J.; WangL.; DongareP.; BrennamanM. K.; PapanikolasJ. M.; MeyerT. J.; ThompsonD. W. Proc. Natl. Acad. Sci. U.S.A. 2016, 113, 11106-11109), does not lead to protonation of the acceptor molecule. Additionally, we propose that association of the complex is likely due to donor-acceptor interactions rather than hydrogen bonding.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-356453 (URN)10.1021/acs.jpca.8b02221 (DOI)000432204200005 ()29641888 (PubMedID)
Conference
18th Meeting on Time-Resolved Vibrational Spectroscopy (TRVS), 2017, Cambridge, ENGLAND
Funder
Swedish Research Council, 2016-04271
Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2018-08-13Bibliographically approved
Parada, G., Kolmar, S., Pettersson-Rimgard, B., Hammarström, L. & Mayer, J. (2018). Marcus inverted region in photo-induced proton coupled electron transfer. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Marcus inverted region in photo-induced proton coupled electron transfer
Show others...
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-367234 (URN)000435539902425 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2018-12-06Bibliographically approved
Hammarström, L. (2018). Mechanisms and distance-dependence of proton-coupled electron transfer. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, USA.. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Mechanisms and distance-dependence of proton-coupled electron transfer
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Washington, D.C.: American Chemical Society (ACS), 2018
National Category
Physical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-368925 (URN)000435539902173 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, USA.
Note

Meeting Abstract: 25

Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
Grigioni, I., Abdellah, M., Corti, A., Dozzi, M. V., Hammarström, L. & Selli, E. (2018). Photoinduced Charge-Tran sfer Dynamics in WO3/BiVO4 Photoanodes Probed through Midinfrared Transient Absorption Spectroscopy. Journal of the American Chemical Society, 140(43), 14042-14045
Open this publication in new window or tab >>Photoinduced Charge-Tran sfer Dynamics in WO3/BiVO4 Photoanodes Probed through Midinfrared Transient Absorption Spectroscopy
Show others...
2018 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 43, p. 14042-14045Article in journal (Refereed) Published
Abstract [en]

The dynamics of photopromoted electrons in BiVO4, WO3, and WO3/BiVO4 heterojunction electrodes has been directly probed by transient absorption (TA) midinfrared (mid-IR) spectroscopy in the picosecond to microsecond time range. By comparison of the dynamics recorded with the two individual oxides at 2050 cm(-1) with that of the heterojunction system after excitation at different wavelengths, electron-transfer processes between selectively excited BiVO4 and WO3 have been directly tracked for the first time. These results support the charge carrier interactions which were previously hypothesized by probing the BiVO4 hole dynamics through TA spectroscopy in the visible range. Nanosecond mid-IR TA experiments confirmed that charge carrier separation occurs in WO3/BiVO4 electrodes under visible-light excitation, persisting up to the microsecond time scale.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-370019 (URN)10.1021/jacs.8b08309 (DOI)000449239700009 ()30296074 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation, 2011:0067Stiftelsen Olle Engkvist Byggmästare, 2016/3
Available from: 2018-12-19 Created: 2018-12-19 Last updated: 2018-12-19Bibliographically approved
Glover, S., Tyburski, R., Liang, L., Tommos, C. & Hammarström, L. (2018). Pourbaix Diagram, Proton-Coupled Electron Transfer, and Decay Kinetics of a Protein Tryptophan Radical: Comparing the Redox Properties of W32• and Y32• Generated Inside the Structurally Characterized α3W and α3Y Proteins. Journal of the American Chemical Society, 140(1), 185-192
Open this publication in new window or tab >>Pourbaix Diagram, Proton-Coupled Electron Transfer, and Decay Kinetics of a Protein Tryptophan Radical: Comparing the Redox Properties of W32 and Y32 Generated Inside the Structurally Characterized α3W and α3Y Proteins
Show others...
2018 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 1, p. 185-192Article in journal (Refereed) Published
Abstract [en]

Protein-based “hole” hopping typically involves spatially arranged redox-active tryptophan or tyrosine residues. Thermodynamic information is scarce for this type of process. The well-structured α3W model protein was studied by protein film square wave voltammetry and transient absorption spectroscopy to obtain a comprehensive thermodynamic and kinetic description of a buried tryptophan residue. A Pourbaix diagram, correlating thermodynamic potentials (E°′) with pH, is reported for W32 in α3W and compared to equivalent data recently presented for Y32 in α3Y (Ravichandran, K. R.; Zong, A. B.; Taguchi, A. T.; Nocera, D. G.; Stubbe, J.; Tommos, C. J. Am. Chem. Soc. 2017, 139, 2994−3004). The α3W Pourbaix diagram displays a pKOX of 3.4, a E°′(W32(N•+/NH)) of 1293 mV, and a E°′(W32(N/NH); pH 7.0) of 1095 ± 4 mV versus the normal hydrogen electrode. W32(N/NH) is 109 ± 4 mV more oxidizing than Y32(O/OH) at pH 5.4–10. In the voltammetry measurements, W32 oxidation–reduction occurs on a time scale of about 4 ms and is coupled to the release and subsequent uptake of one full proton to and from bulk. Kinetic analysis further shows that W32 oxidation likely involves pre-equilibrium electron transfer followed by proton transfer to a water or small water cluster as the primary acceptor. A well-resolved absorption spectrum of W32 is presented, and analysis of decay kinetics show that W32 persists ∼104 times longer than aqueous W due to significant stabilization by the protein. The redox characteristics of W32 and Y32 are discussed relative to global and local protein properties.

Keywords
general trends, can be extracted from the scattered, and limited, information available
National Category
Biophysics Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-343381 (URN)10.1021/jacs.7b08032 (DOI)000422813300044 ()29190082 (PubMedID)
Funder
Swedish Research Council, 621-2012-3926, 2016-04271
Available from: 2018-02-28 Created: 2018-02-28 Last updated: 2018-03-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9933-9084

Search in DiVA

Show all publications