Enhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuning

Handle URI:
http://hdl.handle.net/10754/611202
Title:
Enhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuning
Authors:
Nurlaela, Ela ( 0000-0003-2903-7766 ) ; Wang, Hai; Shinagawa, Tatsuya ( 0000-0002-5240-7342 ) ; Flanagan, Sean; Ould-Chikh, Samy ( 0000-0002-3486-0944 ) ; Qureshi, Muhammad; Mics, Zoltan; Sautet, Philippe; Le Bahers, Tangui; Canovas, Enrique; Bonn, Mischa; Takanabe, Kazuhiro ( 0000-0001-5374-9451 )
Abstract:
Understanding photophysical and electrocatalytic processes during photocatalysis in a powder suspension system is crucial for developing efficient solar energy conversion systems. We report a substantial enhancement by a factor of 3 in photocatalytic effi-ciency for the oxygen evolution reaction (OER) by adding trace amounts (~0.05 wt%) of noble metals (Rh or Ru) to a 2 wt% cobalt oxide-modified Ta3N5 photocatalyst particulate. The optimized system exhibited high quantum efficiencies (QEs) of up to 28 and 8.4% at 500 and 600 nm in 0.1 M Na2S2O8 at pH 14. By isolating the electrochemical components to generate doped cobalt oxide electrodes, the electrocatalytic activity of cobalt oxide when doped with Ru or Rh was improved compared with cobalt oxide, as evidenced by the onset shift for electrochemical OER. Density functional theory (DFT) calculation shows that the ef-fects of a second metal addition perturbs the electronic structure and redox properties in such a way that both hole transfer kinetics and electrocatalytic rates improve. Time resolved terahertz spectroscopy (TRTS) measurement provides evidence of long-lived electron populations (>1 ns; with mobilities μe ~0.1-3 cm2 V-1 s-1), which are not perturbed by the addition of CoOx-related phases. Furthermore, we find that Ta3N5 phases alone suffer ultrafast hole trapping (within 10 ps); the CoOx and M-CoOx decorations most likely induce a kinetic competition between hole transfer toward the CoOx-related phases and trapping in the Ta3N5 phase, which is consistent with the improved OER rates. The present work not only provides a novel way to improve electrocatalytic and photocatalytic performance but also gives additional tools and insight to understand the characteristics of photocatalysts that can be used in a suspension system.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)
Citation:
Enhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuning 2016 ACS Catalysis
Publisher:
American Chemical Society (ACS)
Journal:
ACS Catalysis
Issue Date:
23-May-2016
DOI:
10.1021/acscatal.6b00508
Type:
Article
ISSN:
2155-5435; 2155-5435
Sponsors:
The research reported in this work was supported by the King Abdullah University of Science and Technology. The authors also acknowledge the PSN and IDRIS computation centers for providing calculation resources.
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/acscatal.6b00508
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorNurlaela, Elaen
dc.contributor.authorWang, Haien
dc.contributor.authorShinagawa, Tatsuyaen
dc.contributor.authorFlanagan, Seanen
dc.contributor.authorOuld-Chikh, Samyen
dc.contributor.authorQureshi, Muhammaden
dc.contributor.authorMics, Zoltanen
dc.contributor.authorSautet, Philippeen
dc.contributor.authorLe Bahers, Tanguien
dc.contributor.authorCanovas, Enriqueen
dc.contributor.authorBonn, Mischaen
dc.contributor.authorTakanabe, Kazuhiroen
dc.date.accessioned2016-05-30T13:32:45Z-
dc.date.available2016-05-30T13:32:45Z-
dc.date.issued2016-05-23-
dc.identifier.citationEnhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuning 2016 ACS Catalysisen
dc.identifier.issn2155-5435-
dc.identifier.issn2155-5435-
dc.identifier.doi10.1021/acscatal.6b00508-
dc.identifier.urihttp://hdl.handle.net/10754/611202-
dc.description.abstractUnderstanding photophysical and electrocatalytic processes during photocatalysis in a powder suspension system is crucial for developing efficient solar energy conversion systems. We report a substantial enhancement by a factor of 3 in photocatalytic effi-ciency for the oxygen evolution reaction (OER) by adding trace amounts (~0.05 wt%) of noble metals (Rh or Ru) to a 2 wt% cobalt oxide-modified Ta3N5 photocatalyst particulate. The optimized system exhibited high quantum efficiencies (QEs) of up to 28 and 8.4% at 500 and 600 nm in 0.1 M Na2S2O8 at pH 14. By isolating the electrochemical components to generate doped cobalt oxide electrodes, the electrocatalytic activity of cobalt oxide when doped with Ru or Rh was improved compared with cobalt oxide, as evidenced by the onset shift for electrochemical OER. Density functional theory (DFT) calculation shows that the ef-fects of a second metal addition perturbs the electronic structure and redox properties in such a way that both hole transfer kinetics and electrocatalytic rates improve. Time resolved terahertz spectroscopy (TRTS) measurement provides evidence of long-lived electron populations (>1 ns; with mobilities μe ~0.1-3 cm2 V-1 s-1), which are not perturbed by the addition of CoOx-related phases. Furthermore, we find that Ta3N5 phases alone suffer ultrafast hole trapping (within 10 ps); the CoOx and M-CoOx decorations most likely induce a kinetic competition between hole transfer toward the CoOx-related phases and trapping in the Ta3N5 phase, which is consistent with the improved OER rates. The present work not only provides a novel way to improve electrocatalytic and photocatalytic performance but also gives additional tools and insight to understand the characteristics of photocatalysts that can be used in a suspension system.en
dc.description.sponsorshipThe research reported in this work was supported by the King Abdullah University of Science and Technology. The authors also acknowledge the PSN and IDRIS computation centers for providing calculation resources.en
dc.language.isoenen
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/acscatal.6b00508en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acscatal.6b00508.en
dc.titleEnhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuningen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalACS Catalysisen
dc.eprint.versionPost-printen
dc.contributor.institutionDepartment of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germanyen
dc.contributor.institutionGraduate School of Material Science in Mainz, University of Mainz, Staudingerweg 9, 55128 Mainz, Germanyen
dc.contributor.institutionUniversité de Lyon, Université Claude Bernard Lyon 1, ENS Lyon, Centre Nationale de Recherche Scientifique, 46 allée d’Italie, 69007 Lyon Cedex 07, Franceen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorNurlaela, Elaen
kaust.authorShinagawa, Tatsuyaen
kaust.authorFlanagan, Seanen
kaust.authorOuld-Chikh, Samyen
kaust.authorQureshi, Muhammaden
kaust.authorTakanabe, Kazuhiroen
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