Thin films of rutile quantum-size nanowires as electrodes:: Photoelectrochemical studies

被引:37
作者
Berger, Thomas
Lana-Villarreal, Teresa
Monllor-Satoca, Damian
Gomez, Roberto [1 ]
机构
[1] Univ Alicante, Inst Univ Electroquim, E-03080 Alicante, Spain
基金
奥地利科学基金会;
关键词
D O I
10.1021/jp8049747
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Transparent electrodes, formed by 50 rim bundles of rutile nanowires (NW), 2 nm in diameter, have been prepared directly by chemical bath deposition at low temperature on conducting glass. The photoelectrocatalytic behavior of such NW electrodes has been studied in acidic solutions in the presence of model organic molecules (formic acid and methanol) and has been compared with that characteristic of thin films consisting of larger (20 x 40 nm) ellipsoidal rutile nanoparticles (NP). Both UV-vis absorption and photoaction spectra evidence that the NWs are in the quantum confinement (QC) regime, as the band gap is 0.27 eV larger than that of the ellipsoidal nanoparticles. From the onset of the accumulation region, determined by voltammetry, the conduction band edge is estimated to shift upward around 0.06 eV as a result of QC. In the presence of efficient hole acceptors, significantly larger photocurrents were observed for NW films than for NP electrodes. This indicates that the morphology of the film, together with the existence of QC and the particular surface structure of the wires, confers to the corresponding electrodes particularly good photoelectrocatalytic properties. A simple model based on the electron diffusion equation is applied to rationalize the observed photoelectrochemical behavior. The results point to an efficient hole transfer and, particularly, to a diminished electron recombination due to the absence of intergrain boundaries in NW electrodes as compared to NP electrodes. Complementarily, the reactivity of the photogenerated electrons was assessed through photopotential measurements, which also reflect an increased reactivity of electrons toward oxygen in the case of NW films.
引用
收藏
页码:15920 / 15928
页数:9
相关论文
共 50 条
[1]  
[Anonymous], 2001, ELECTROCHEMISTRY NAN
[2]   PHOTOCATALYTIC HYDROGENATION OF CH3CCH WITH H2O ON SMALL-PARTICLE TIO2 - SIZE QUANTIZATION EFFECTS AND REACTION INTERMEDIATES [J].
ANPO, M ;
SHIMA, T ;
KODAMA, S ;
KUBOKAWA, Y .
JOURNAL OF PHYSICAL CHEMISTRY, 1987, 91 (16) :4305-4310
[3]   PHOTOCATALYTIC REDUCTION OF CO2 WITH H2O ON VARIOUS TITANIUM-OXIDE CATALYSTS [J].
ANPO, M ;
YAMASHITA, H ;
ICHIHASHI, Y ;
EHARA, S .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1995, 396 (1-2) :21-26
[4]   Apparent two-dimensional behavior of TiO2 nanotubes revealed by light absorption and luminescence [J].
Bavykin, DV ;
Gordeev, SN ;
Moskalenko, AV ;
Lapkin, AA ;
Walsh, FC .
JOURNAL OF PHYSICAL CHEMISTRY B, 2005, 109 (18) :8565-8569
[5]   Nanowire-based dye-sensitized solar cells [J].
Baxter, JB ;
Aydil, ES .
APPLIED PHYSICS LETTERS, 2005, 86 (05) :1-3
[6]   Enhancement and limits of the photoelectrochemical response from anodic TiO2 nanotubes -: art. no. 243114 [J].
Beranek, R ;
Tsuchiya, H ;
Sugishima, T ;
Macak, JM ;
Taveira, L ;
Fujimoto, S ;
Kisch, H ;
Schmuki, P .
APPLIED PHYSICS LETTERS, 2005, 87 (24) :1-3
[7]  
BERGER T, LANGMUIR UNPUB
[8]   The electrochemistry of transparent quantum size rutile nanowire thin films prepared by one-step low temperature chemical bath deposition [J].
Berger, Thomas ;
Lana-Villarreal, Teresa ;
Monllor-Satoca, Damian ;
Gomez, Roberto .
CHEMICAL PHYSICS LETTERS, 2007, 447 (1-3) :91-95
[9]   An electrochemical study on the nature of trap states in nanocrystalline rutile thin films [J].
Berger, Thomas ;
Lana-Villarreal, Teresa ;
Monllor-Satoca, Damian ;
Gomez, Roberto .
JOURNAL OF PHYSICAL CHEMISTRY C, 2007, 111 (27) :9936-9942
[10]   Charge transfer reductive doping of nanostructured TiO2 thin film's as a way to improve their photoelectrocatalytic performance [J].
Berger, Thomas ;
Lana-Villarreal, Teresa ;
Monllor-Satoca, Damian ;
Gomez, Roberto .
ELECTROCHEMISTRY COMMUNICATIONS, 2006, 8 (11) :1713-1718