Electronic Resource
Unraveling the cooperative mechanism of visible-light absorption in bulk N,Nb codoped TiO2 powders of nanomaterials
| العنوان: | Unraveling the cooperative mechanism of visible-light absorption in bulk N,Nb codoped TiO2 powders of nanomaterials |
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| المؤلفون: | Marchiori, C, Di Liberto, G, Soliveri, G, Loconte, L, Lo Presti, L, Meroni, D, Ceotto, M, Oliva, C, Cappelli, S, Cappelletti, G, Aieta, C, Ardizzone, S, C. Marchiori, G. Di Liberto, G. Soliveri, L. Loconte, L. Lo Presti, D. Meroni, M. Ceotto, C. Oliva, S. Cappelli, G. Cappelletti, C. Aieta, S. Ardizzone |
| بيانات النشر: | 2014 |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | N,Nb-codoping has recently been proposed as a promising strategy to enhance the activity of nanostructured TiO2 under visible irradiation. Here, we suggest a possible electronic mechanism to account for the observed visible absorption improvement. The effects of N and Nb species on the electronic, crystallographic, and morphological properties of TiO2 were deeply investigated both experimentally (HRXRPD, EXAFS, EDX, BET, SEM, EPR, and DRS) and theoretically (DFT). We found a significant synergism between N and Nb species, while EXAFS, HR-XRPD, and DFT simulations provided compelling evidence for the Nb substitutional position in anatase. At variance with interstitial, substitutional Nb can transfer an electron to low-energy valence states of the N codopant near the valence band. This intrinsic charge compensation mechanism is substantiated by EPR, which shows a reduction of the paramagnetic bulk N species signal in N,Nb-codoped samples. DRS analysis of N,Nb-codoped samples shows a slight reduction of the apparent band gap and a significantly increased visible-light absorbance. This effect is due to the shallow midgap states created by Nb (below conduction band) and N (above valence band). DFT results suggest that substitutional Nb ions transfer electrons to low-lying guest N states within the band gap, eventually enhancing the light absorption. |
| مصطلحات الفهرس: | Nb, N-doped TiO2, microstructure, nanostructure, point defect, DFT calculation, EPR measurements, info:eu-repo/semantics/article |
| URL: | info:eu-repo/semantics/altIdentifier/wos/WOS:000343333600078 volume:118 issue:41 firstpage:24152 lastpage:24164 numberofpages:13 journal:JOURNAL OF PHYSICAL CHEMISTRY. C |
| الاتاحة: | Open access content. Open access content info:eu-repo/semantics/closedAccess |
| ملاحظة: | English |
| Other Numbers: | ITBAO oai:boa.unimib.it:10281/289111 10.1021/jp507143z info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-84949116582 1308936314 |
| المصدر المساهم: | BICOCCA OPEN ARCH From OAIster®, provided by the OCLC Cooperative. |
| رقم الانضمام: | edsoai.on1308936314 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |