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dc.contributor.authorTu, W
dc.contributor.authorXu, Y
dc.contributor.authorWang, J
dc.contributor.authorZhang, B
dc.contributor.authorZhou, T
dc.contributor.authorYin, S
dc.contributor.authorWu, S
dc.contributor.authorLi, C
dc.contributor.authorHuang, Y
dc.contributor.authorZhou, Y
dc.contributor.authorZou, Z
dc.contributor.authorRobertson, J
dc.contributor.authorKraft, M
dc.contributor.authorXu, R
dc.date.accessioned2018-11-24T00:30:36Z
dc.date.available2018-11-24T00:30:36Z
dc.date.issued2017-08-07
dc.identifier.issn2168-0485
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/285915
dc.description.abstractVacancy engineering, that is, self-doping of vacancy in semiconductors, has become a commonly used strategy to tune the photocatalytic performances. However, there still lacks fundamental understanding of the role of the vacancies in semiconductor materials. Herein, the g-C$_{3}$N$_{4}$ nanosheets with tunable nitrogen vacancies are prepared as the photocatalysts for H$_{2}$ evolution and CO$_{2}$ reduction to CO. On the basis of both experimental investigation and DFT calculations, nitrogen vacancies in g-C$_{3}$N$_{4}$ induce the formation of midgap states under the conduction band edge. The position of midgap states becomes deeper with the increasing of nitrogen vacancies. The g-C$_{3}$N$_{4}$ nanosheets with the optimized density of nitrogen vacancies display about 18 times and 4 times enhancement for H$_{2}$ evolution and of CO$_{2}$ reduction to CO, respectively, as compared to the bulk g-C$_{3}$N$_{4}$. This is attributed to the synergistic effects of several factors including (1) nitrogen vacancies cause the excitation of electrons to midgap states below the conduction band edge, which results in extension of the visible light absorption to photons of longer wavelengths (up to 598 nm); (2) the suitable midgap states could trap photogenerated electrons to minimize the recombination loss of photogenerated electron–hole pairs; and (3) nitrogen vacancies lead to uniformly anchored small Pt nanoparticles (1–2 nm) on g-C$_{3}$N$_{4}$, and facilitate the electron transfer to Pt. However, the overintroduction of nitrogen vacancies generates deeper midgap states as the recombination centers, which results in deterioration of photocatalytic activities. Our work is expected to provide new insights for fabrication of nanomaterials with suitable vacancies for solar fuel generation.
dc.description.sponsorshipWe acknowledge the financial support from Nanyang Technological University and Cambridge Centre for Carbon Reduction in Chemical Technology (C4T) CREATE Programmes.
dc.publisherAmerican Chemical Society
dc.subjectg-C$_{3}$N$_{4}$
dc.subjectmidgap states
dc.subjectnitrogen vacancy
dc.subjectphotocatalysis
dc.titleInvestigating the Role of Tunable Nitrogen Vacancies in Graphitic Carbon Nitride Nanosheets for Efficient Visible-Light-Driven H$_{2}$ Evolution and CO$_{2}$ Reduction
dc.typeArticle
prism.endingPage7268
prism.issueIdentifier8
prism.publicationDate2017
prism.publicationNameACS Sustainable Chemistry and Engineering
prism.startingPage7260
prism.volume5
dc.identifier.doi10.17863/CAM.33244
rioxxterms.versionofrecord10.1021/acssuschemeng.7b01477
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserved
rioxxterms.licenseref.startdate2017-08-07
dc.contributor.orcidKraft, Markus [0000-0002-4293-8924]
dc.identifier.eissn2168-0485
rioxxterms.typeJournal Article/Review
pubs.funder-project-idNational Research Foundation Singapore (via Cambridge Centre for Advanced Research and Education in Singapore (CARES)) (unknown)
cam.issuedOnline2017-07-05
rioxxterms.freetoread.startdate2018-07-05


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