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Ji, Y. & Luo, Y. (2019). Direct Donation of Protons from H2O to CO2 in Artificial Photosynthesis on the Anatase TiO2(101) Surface. The Journal of Physical Chemistry C, 123(5), 3019-3023
Open this publication in new window or tab >>Direct Donation of Protons from H2O to CO2 in Artificial Photosynthesis on the Anatase TiO2(101) Surface
2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 5, p. 3019-3023Article in journal (Refereed) Published
Abstract [en]

Conversion of CO2 and H2O into value-added organic molecules via artificial photosynthesis is a promising solution to current energy and environment problems. In the reaction, it is generally believed that CO2 is converted into organic molecules by photogenerated electrons and protons that result from photo-oxidation of H2O. In this work, we investigate the possibility that H2O, without being oxidized, directly donates protons to CO2 and other intermediates adsorbed at the oxygen vacancy on the anatase TiO2(101) surface. We found that this can greatly lower the barriers (by about 0.3 eV) for the hydrogenation of CO2, CO, H2CO, and CH3O because less energy is required to displace these adsorbates to accept the proton (in H2O). The OH- group produced in these reactions can recombine with a surface-adsorbed proton to form a new H2O molecule, making H2O a shuttling center of the adsorbed protons, or it can take part in the oxygen evolution reaction with a lower barrier. The results suggest that H2O can play multiple roles in artificial photosynthesis and the reduction and oxidation parts of the reaction may have synergistic effects.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-245143 (URN)10.1021/acs.jpcc.8b11936 (DOI)000458348600035 ()2-s2.0-85061325805 (Scopus ID)
Note

QC 20190313

Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-03-13Bibliographically approved
Ma, Y., Lin, J., Song, X.-N. -., Wang, C.-K. -., Hua, W. & Luo, Y. (2019). Local structures of nitrogen doped graphdiynes determined by computational X-ray spectroscopy. Carbon, 149, 672-678
Open this publication in new window or tab >>Local structures of nitrogen doped graphdiynes determined by computational X-ray spectroscopy
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2019 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 149, p. 672-678Article in journal (Refereed) Published
Abstract [en]

Nitrogen doping is an important method to modulate electronic structure of two-dimensional carbon materials. The properties of the doped systems are heavily dependent on the local structure of nitrogen dopants involved, which are often determined by experimental X-ray photoelectron spectra (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) at the nitrogen K-edge. In the present work, the N1s XPS and NEXAFS spectra of nitrogen-doped graphdiynes have been accurately calculated at the density functional theory level. Five representative nitrogen-dopants in graphdiynes, namely [pyridinic, amino, graphitic, and two sp-hybridized N (sp-N-1 and sp-N-2) local structures], are fully examined, from which all experimental features could be correctly assigned. The calculated results can be used to determine the ratio of different nitrogen dopants in graphdiyne at different elevated temperatures reported in previous experiments. Our findings provide the basic references for structure determination of nitrogen doped graphdiyne and new understanding of the underlying structure-property relationships.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Density functional calculation, Graphdiyne, Near-edge X-ray absorption fine-structure spectroscopy, Nitrogen-doping, X-ray photoelectron spectroscopy, Computation theory, Density functional theory, Doping (additives), Electronic structure, Photoelectron spectroscopy, Photoelectrons, Photons, X ray absorption, X ray absorption near edge structure spectroscopy, X ray photoelectron spectroscopy, Elevated temperature, Local structure, Near edge x ray absorption fine structure, Structure determination, Structure property relationships, X ray photoelectron spectra, Nitrogen
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:kth:diva-252490 (URN)10.1016/j.carbon.2019.04.045 (DOI)000471602000075 ()2-s2.0-85065060311 (Scopus ID)
Note

QC 20190712

Available from: 2019-07-12 Created: 2019-07-12 Last updated: 2019-07-29Bibliographically approved
Li, X., Duan, S., Liu, H., Chen, G., Luo, Y. & Ågren, H. (2019). Mechanism for the Extremely Efficient Sensitization of Yb(3+)Luminescence in CsPbCl3 Nanocrystals. Journal of Physical Chemistry Letters, 10(3), 487-492
Open this publication in new window or tab >>Mechanism for the Extremely Efficient Sensitization of Yb(3+)Luminescence in CsPbCl3 Nanocrystals
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2019 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, no 3, p. 487-492Article in journal (Refereed) Published
Abstract [en]

Rare earth ion (RE3+)-doped inorganic CsPbX3 (X = Cl or Cl/Br) nanocrystals have been presented as promising materials for applications in solar-energy conversion technology. An extremely efficient sensitization of Yb3+ luminescence in CsPbCl3 nanoparticles (NCs) was very recently demonstrated where quantum cutting is responsible for the performance of photoluminescence quantum yields over 100% (T. J. Milstein, et al. Nano Letters 2018, 18, 3792). In the present work, based on the cubic phase of inorganic perovskite, we seek to obtain atom-level insight into the basic mechanisms behind these observations in order to boost the further development of RE3+-doped CsPbX3 NCs for optoelectronics. In our calculations of cubic crystal structure, we do not find any energy level formed in the middle of the band gap, which disfavors a mechanism of stepwise energy transfer from the perovskite host to two Yb3+ ions. Our work indicates that the configuration with "right-angle" Yb3+-V-Pb-Yb3+ couple is most likely to form in Yb3+-doped CsPbCl3. Associated with this "right-angle" couple, the "right-angle" Pb atom with trapped excited states would localize the photogenerated electrons and act as the energy donor in a quantum cutting process, which achieves simultaneous sensitization of two neighboring Yb3+ ions.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-245142 (URN)10.1021/acs.jpclett.8b03406 (DOI)000458704800026 ()30642182 (PubMedID)
Note

QC 20190313

Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-05-20Bibliographically approved
Xie, Z., Duan, S., Wang, C.-K. & Luo, Y. (2019). Monitoring Hydrogen/Deuterium Tautomerization in Transient Isomers of Single Porphine by Highly Localized Plasmonic Field. The Journal of Physical Chemistry C, 123(17), 11081-11093
Open this publication in new window or tab >>Monitoring Hydrogen/Deuterium Tautomerization in Transient Isomers of Single Porphine by Highly Localized Plasmonic Field
2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 17, p. 11081-11093Article in journal (Refereed) Published
Abstract [en]

Inner proton transfer between two trans isomers (tautomerization) in porphyrins plays a crucial role in many biological systems as well as molecular nanotechnology. Although the stepwise mechanism of tautomerization is well accepted, the involved intermediate cis-isomer has not been directly detected owing to its short lifetime and the extremely low intensities of corresponding hydrogen vibrations. Here, taking a single porphine as the prototype, we theoretically demonstrate that Raman intensities of the hydrogen vibrations become accessible under the highly localized plasmonic field because of the symmetry breaking effect. In addition, with the ultrafast incident excitations, we find that Raman signals of cis-porphine could be distinguished from the stable trans isomer, suggesting a general protocol for the direct characterization of transient isomers. Moreover, calculated results reveal that the position of inner hydrogen/deuterium can be unambiguously visualized from Raman images of the corresponding stretching modes, providing a unique optical means for the chemical monitoring of tautomerization in porphine and its derivatives.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-252384 (URN)10.1021/acs.jpcc.9b00398 (DOI)000466988600040 ()2-s2.0-85065302261 (Scopus ID)
Note

QC 20190618

Available from: 2019-06-18 Created: 2019-06-18 Last updated: 2019-06-18Bibliographically approved
Li, X., Duan, S., Liu, H., Chen, G., Luo, Y. & Ågren, H. (2019). On the Mechanism for the Extremely Efficient Sensitization of Yb3+ Luminescence in CsPbCl3 Nanocrystals. Journal of Physical Chemistry Letters, 10(3), 487-492
Open this publication in new window or tab >>On the Mechanism for the Extremely Efficient Sensitization of Yb3+ Luminescence in CsPbCl3 Nanocrystals
Show others...
2019 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, no 3, p. 487-492Article in journal (Refereed) Published
Abstract [en]

Rare earth ion (RE3+)-doped inorganic CsPbX3 (X = Cl or Cl/Br) nanocrystals have been presented as promising materials for applications in solar-energy conversion technology. An extremely efficient sensitization of Yb3+ luminescence in CsPbCl3 nanoparticles (NCs) was very recently demonstrated where quantum cutting is responsible for the performance of photoluminescence quantum yields over 100% (T. J. Milstein, et al. Nano Letters 2018, 18, 3792). In the present work, based on the cubic phase of inorganic perovskite, we seek to obtain atom-level insight into the basic mechanisms behind these observations in order to boost the further development of RE3+-doped CsPbX3 NCs for optoelectronics. In our calculations of cubic crystal structure, we do not find any energy level formed in the middle of the band gap, which disfavors a mechanism of stepwise energy transfer from the perovskite host to two Yb3+ ions. Our work indicates that the configuration with "right-angle" Yb3+-V-Pb-Yb3+ couple is most likely to form in Yb3+-doped CsPbCl3. Associated with this "right-angle" couple, the "right-angle" Pb atom with trapped excited states would localize the photogenerated electrons and act as the energy donor in a quantum cutting process, which achieves simultaneous sensitization of two neighboring Yb3+ ions.

National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-246213 (URN)10.1021/acs.jpclett.8b03406 (DOI)000458704800026 ()2-s2.0-85061130625 (Scopus ID)
Note

QC 20190318

Available from: 2019-03-16 Created: 2019-03-16 Last updated: 2019-05-10Bibliographically approved
Hu, W., Cao, X., Zhang, Y., Li, T., Jiang, J. & Luo, Y. (2019). Tunable Single-Photon Emission by Defective Boron-Nitride Nanotubes for High-Precision Force Detection. The Journal of Physical Chemistry C, 123(14), 9624-9628
Open this publication in new window or tab >>Tunable Single-Photon Emission by Defective Boron-Nitride Nanotubes for High-Precision Force Detection
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2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 14, p. 9624-9628Article in journal (Refereed) Published
Abstract [en]

Boron-nitride nanotubes (BNNTs) hold great potential for electronic, optical, and mechanical applications. By introducing a NBVN defect of removing one nitrogen atom while replacing one boron by nitrogen atom, we examined the use of defective NBVN@BNNTs as a novel type of single-photon emission (SPE) material. Using first-principles calculations to reveal the electronic structures of NBVN@BNNTs, we found that SPE with 1.45-2.29 eV energy can be generated in NBVN@BNNTs with size ranging from (5,0) to (10,0). It is also intriguing to find that their SPE responses are sensitive to the external forces, as indicated by the computed potential energy surfaces and dielectric tensors. Specifically, the (7,0) NBVN@BNNT can serve as an ideal force detector due to its sensitivity and linear response to external force. However, the (5,0) and (6,0) NBVN@BNNTs exhibit insensitive SPE with respect to force applied, and the detection ability of the (8,0), (9,0), and (10,0) NBVN@BNNTs are limited due to the emergence of new photon emissions when tensions become larger than 10 nN. These findings would open a new door for utilizing defective BNNTs for SPE and mechanical detection applications.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-251491 (URN)10.1021/acs.jpcc.9b01651 (DOI)000464768600129 ()2-s2.0-85064344387 (Scopus ID)
Note

QC 20190522

Available from: 2019-05-22 Created: 2019-05-22 Last updated: 2019-05-22Bibliographically approved
Li, J., Luo, Y. & Zhang, J. (2018). A theoretical study on vibronic spectra and photo conversation process of protonated naphthalenes. Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, 205, 520-527
Open this publication in new window or tab >>A theoretical study on vibronic spectra and photo conversation process of protonated naphthalenes
2018 (English)In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 205, p. 520-527Article in journal (Refereed) Published
Abstract [en]

The equilibrium structures and vibrational frequencies of the ground state and several singlet low-lying excited states of alpha-and beta-protonated naphthalenes (alpha-and beta-HN+) have been studied by time -dependent density -functional theory (TD-DFT). Within the Franck -Condon approximation, vibronic absorption spectra of alpha-HN+ and beta-HN+, together with the vibronic emission spectrum of alpha-HN+, have been calculated. The obtained good agreement between the theoretical and experimental spectra enables to correctly assign vibronic features in both absorption and emission spectra. Moreover, the non -radiative deactivation pathway from the low-lying excite states to the ground state in alpha-HN+ and beta-HN+, as well as the photo-induce proton transfer pathway, are investigated at the CASPT2/CASSCF/6-31G* level. Our study is helpful for understanding the photochemical behavior of these important polycyclic aromatic hydrocarbon molecules.

Place, publisher, year, edition, pages
Pergamon Press, 2018
Keywords
Vibronic spectra, Photo conversation, Theoretical study, Protonated naphthalenes
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:kth:diva-235992 (URN)10.1016/j.saa.2018.07.074 (DOI)000445713600061 ()30071500 (PubMedID)2-s2.0-85050638025 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20181015

Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2019-01-18Bibliographically approved
Xie, Z., Duan, S., Tian, G., Wang, C.-K. & Luo, Y. (2018). Theoretical modeling of tip-enhanced resonance Raman images of switchable azobenzene molecules on Au(111). Nanoscale, 10(25), 11850-11860
Open this publication in new window or tab >>Theoretical modeling of tip-enhanced resonance Raman images of switchable azobenzene molecules on Au(111)
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2018 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, no 25, p. 11850-11860Article in journal (Refereed) Published
Abstract [en]

With a highly localized plasmonic field, tip-enhanced Raman spectroscopy (TERS) images have reached atomic-scale resolution, providing an optical means to explore the structure of a single molecule. We have applied the recently developed theoretical method to simulate the TERS images of trans and cis azobenzene as well as its derivatives on Au(111). Our theoretical results reveal that when the first excited state is resonantly excited, TERS images from a highly confined plasmonic field can effectively distinguish the isomer configurations of the adsorbates. The decay of the plasmonic field along the surface normal can be further used to distinguish different nonplanar cis configurations. Moreover, subtle characteristics of different molecular configurations can also be identified from the TERS images of other resonant excited states with a super-high confined plasmonic field. These findings serve as good references for future TERS experiments on molecular isomers.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-232390 (URN)10.1039/c8nr01988f (DOI)000437761500015 ()29897090 (PubMedID)2-s2.0-85049505191 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20180727

Available from: 2018-07-27 Created: 2018-07-27 Last updated: 2018-07-27Bibliographically approved
Liu, J., Ji, Y., Nai, J., Niu, X., Luo, Y., Guo, L. & Yang, S. (2018). Ultrathin amorphous cobalt-vanadium hydr(oxy)oxide catalysts for the oxygen evolution reaction. Energy & Environmental Science, 11(7), 1736-1741
Open this publication in new window or tab >>Ultrathin amorphous cobalt-vanadium hydr(oxy)oxide catalysts for the oxygen evolution reaction
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2018 (English)In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 11, no 7, p. 1736-1741Article in journal (Refereed) Published
Abstract [en]

Cost efficient and long-term stable catalysts are in great demand for the oxygen evolution reaction (OER), a key process involved in water splitting cells and metal-air batteries. Here, we demonstrate that the ultrathin amorphous cobalt-vanadium hydr(oxy)oxide we synthesized is a highly promising electrocatalytic material for the OER with a low overpotential of 0.250 V (even lower down to 0.215 V when supported on Au foam) at 10 mA cm(-2) and a long stable operation time (170 h) in alkaline media. In combination with in situ X-ray absorption spectral characterization and first-principles simulations, we reveal that the ultrathin, amorphous and alloyed structural characteristics have enabled its facile transformation to the desirable active phase, leading to a dramatically enhanced catalytic activity. Our finding highlights the remarkable advantages of the two-dimensional amorphous material and sheds new light on the design of high-performance electrocatalysts.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-232621 (URN)10.1039/c8ee00611c (DOI)000438392400008 ()2-s2.0-85050152583 (Scopus ID)
Note

QC 20180730

Available from: 2018-07-30 Created: 2018-07-30 Last updated: 2019-08-20Bibliographically approved
Tan, S., Feng, H., Ji, Y., Zheng, Q., Shi, Y., Zhao, J., . . . Hou, J. G. (2018). Visualizing Elementary Reactions of Methanol by Electrons and Holes on TiO2(110) Surface. The Journal of Physical Chemistry C, 122(50), 28805-28814
Open this publication in new window or tab >>Visualizing Elementary Reactions of Methanol by Electrons and Holes on TiO2(110) Surface
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 50, p. 28805-28814Article in journal (Refereed) Published
Abstract [en]

Direct visualization and comparison of the elementary reactions induced by electrons and holes are of importance for finding a way to conduct chemical reactions and reaction sequences in a controllable manner. As a semiconductor, TiO2 provides a playground to perform the measurements, and moreover, the information can be useful for design of high-performance TiO2-based catalysts and photocatalysts. Here, we present our investigation on the elementary reactions of CH3OH on TiO2 surface through visualization of specific elementary steps by highly controllable electron and hole injection using scanning tunneling microscopy. The distinct sequential routes and their kinetics, namely, breaking C-O and O-H bonds by electrons and breaking O-H and C-H bonds by holes, respectively, have been experimentally identified and well elucidated by density functional theory calculations. Our nonlocal h-injection experimental and theoretical results suggest that the delocalized holes in the TiO2 substrate should be responsible for the temperature-dependent h-route reactions. The locally triggered e-route reaction is associated with the fact that the location of the unoccupied hybridization states is much higher than that of the conduction band onset. Our findings resolve the long-standing debate about the intermediate species and reaction mechanism in photocatalytic oxidation of CH3OH. Our proposed protocol offers a powerful means to study elementary reactions induced by electrons and holes on a semiconductor surface in general.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-241328 (URN)10.1021/acs.jpcc.8b09784 (DOI)000454566700036 ()2-s2.0-85058525958 (Scopus ID)
Note

QC 20190123

Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2019-01-23Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0007-0394

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