Photogenerated Defects in Shape-Controlled TiO2 Anatase Nanocrystals: A Probe To Evaluate the Role of Crystal Facets in Photocatalytic Processes

被引:325
作者
D'Arienzo, Massimiliano [1 ]
Carbajo, Jaime [2 ]
Bahamonde, Ana [2 ]
Crippa, Maurizio [1 ]
Polizzi, Stefano [3 ]
Scotti, Roberto [1 ]
Wahba, Laura [1 ]
Morazzoni, Franca [1 ]
机构
[1] Univ Milano Bicocca, Dept Mat Sci, INSTM, I-20125 Milan, Italy
[2] ICP CSIC, Inst Catalisis & Petroleoquim, Madrid 28049, Spain
[3] Univ Ca Foscari Venezia, Dipartimento Sci Mol & Nanosistemi, I-30172 Venice, Italy
关键词
EXPOSED; 001; FACETS; TITANIUM-DIOXIDE; SURFACE SCIENCE; RUTILE; PHASE; NANOSHEETS; NANORODS; PERCENTAGE; PARTICLES; GROWTH;
D O I
10.1021/ja204838s
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The promising properties of anatase TiO2 nanocrystals exposing specific surfaces have been investigated in depth both theoretically and experimentally. However, a dear assessment of the role of the crystal faces in photocatalytic processes is still under debate. In order to clarify this issue, we have comprehensively explored the properties of the photogenerated defects and in particular their dependence on the exposed crystal faces in shape-controlled anatase. Nanocrystals were synthesized by solvothermal reaction of titanium butoxide in the presence of oleic acid and oleylamine as morphology-directing agents, and their photocatalytic performances were evaluated in the phenol mineralization in aqueous media, using O-2 as the oxidizing agent The charge trapping centers, Ti3+, O- and O-2(-), formed by UV irradiation of the Catalyst were detected by electron spin resonance, and their abundance and reactivity were related to the exposed crystal. faces and to the photoefficiency of the nanocrystals. In vacuum conditions, the concentration of trapped holes (O- centers) increases with increasing {001} surface area and photoactivity, while the amount of Ti3+ centers increases with the specific surface area of {101} facets, and the highest value occurs for the sample with the worst photooxidative efficacy. These results suggest that {001} surfaces can be considered essentially as Oxidation sites with a key role in the photoxidation, while {101} surfaces provide reductive sites which do not directly assist the oxidative processes. Photoexcitation experiments in O-2 atmosphere led to the formation of Ti4+-O-2(-) oxidant species mainly located on {101} faces, confirming the indirect contribution of these surfaces to the photooxidative processes. Although this work focuses on the properties of TiO2, we expect that the presented quantitative investigation may provide. a new methodological tool for a more effective evaluation of the role of metal oxide crystal faces in photocatalytic processes.
引用
收藏
页码:17652 / 17661
页数:10
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共 60 条
[1]   Application of EPR spectroscopy for elucidation of vanadium speciation in VOx/ZrO2 catalysts subject to redox treatment [J].
Adamski, A ;
Spalek, T ;
Sojka, Z .
RESEARCH ON CHEMICAL INTERMEDIATES, 2003, 29 (7-9) :793-804
[2]   Effect of chemical etching by sulfuric acid or H2O2-NH3 mixed solution on the photocatalytic activity of rutile TiO2 nanorods [J].
Bae, Eunyoung ;
Murakami, Naoya ;
Nakamura, Misa ;
Ohno, Teruhisa .
APPLIED CATALYSIS A-GENERAL, 2010, 380 (1-2) :48-54
[3]   Exposed crystal surface-controlled rutile TiO2 nanorods prepared by hydrothermal treatment in the presence of poly(vinyl pyrrolidone) [J].
Bae, Eunyoung ;
Ohno, Teruhisa .
APPLIED CATALYSIS B-ENVIRONMENTAL, 2009, 91 (3-4) :634-639
[4]   Exposed crystal surface-controlled TiO2 nanorods having rutile phase from TiCl3 under hydrothermal conditions [J].
Bae, Eunyoung ;
Murakami, Naoya ;
Ohno, Teruhisa .
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL, 2009, 300 (1-2) :72-79
[5]   Prediction of TiO2 nanoparticle phase and shape transitions controlled by surface chemistry [J].
Barnard, AS ;
Curtiss, LA .
NANO LETTERS, 2005, 5 (07) :1261-1266
[6]   THE DETERMINATION OF PORE VOLUME AND AREA DISTRIBUTIONS IN POROUS SUBSTANCES .1. COMPUTATIONS FROM NITROGEN ISOTHERMS [J].
BARRETT, EP ;
JOYNER, LG ;
HALENDA, PP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1951, 73 (01) :373-380
[7]   UV induced local heating effects in TiO2 nanocrystals [J].
Berger, T ;
Diwald, O ;
Knözinger, E ;
Sterrer, M ;
Yates, JT .
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2006, 8 (15) :1822-1826
[8]   Light-induced charge separation in anatase TiO2 particles [J].
Berger, T ;
Sterrer, M ;
Diwald, O ;
Knözinger, E ;
Panayotov, D ;
Thompson, TL ;
Yates, JT .
JOURNAL OF PHYSICAL CHEMISTRY B, 2005, 109 (13) :6061-6068
[9]   Adsorption of gases in multimolecular layers [J].
Brunauer, S ;
Emmett, PH ;
Teller, E .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1938, 60 :309-319
[10]   Evidence for O2- radical stabilization at surface oxygen vacancies on polycrystalline TiO2 [J].
Carter, Emma ;
Carley, Albert F. ;
Murphy, Damien M. .
JOURNAL OF PHYSICAL CHEMISTRY C, 2007, 111 (28) :10630-10638