半导体光催化在环境保护和未来新能源开发等领域中具有重要的作用和意义. 由于参与光催化反应的主体是光生载流子,并涉及光生电子和空穴的界面转移与复合,(光)电化学方法是研究光催化反应微观动力学和机理的重要手段. 本文主要介绍本课题组应用这类研究方法在液相光催化去污方面所获得的部分研究结果,并对今后研究重点提出了某些看法.
Semiconductor photocatalysis plays a critical role in the environment protection and future energy development. (Photo)electrochemical measurements are powerful tools for studying the kinetics and mechanism of photocatalytic reactions, since photo-carriers, as reactants of photocatalytic reactions, are involved in the interfacial transfer and recombination of semiconductor/electrolyte interface. This review describes the part of our recent results regarding aqueous photocatalytic decontamination obtained by these methods, and the focus of future work in this field is suggested.
[1] Fujishima A, Honda K. Electrochemical photolysis of water at a semiconductor electrode[J]. Nature, 1972, 238(5358): 37-38.
[2] Chen C, Ma W, Zhao J. Semiconductor-mediated photodegradation of pollutants under visible-light irradiation[J]. Chemical Society Reviews, 2010, 39(11): 4206-4219.
[3] Hoffmann M R, Martin S T, Choi W, et al. Environmental applications of semiconductor photocatalysis[J]. Chemical Reviews, 1995, 95(1): 69-96.
[4] Leng W H, Zhang Z, Zhang J Q, et al. Investigation of the kinetics of a TiO2 photoelectrocatalytic reaction involving charge transfer and recombination through surface states by electrochemical impedance spectroscopy[J]. Journal of Physical Chemistry B, 2005, 109(31): 15008-15023.
[5] Cowan A J, Tang J, Leng W, et al. Water splitting by nanocrystalline TiO2 in a complete photoelectrochemical cell exhibits efficiencies limited by charge recombination[J]. Journal of Physical Chemistry C, 2010, 114(9): 4208-4214.
[6] Leng W H, Barnes P R F, Juozapavicius M, et al. Electron diffusion length in mesoporous nanocrystalline TiO2 photoelectrodes during water oxidation[J]. Journal of Physical Chemistry Letters, 2010, 1(6): 967-972.
[7] Hagfeldt A, Graetzel M. Light-induced redox reactions in nanocrystalline systems[J]. Chemical Reviews, 1995, 95(1): 49-68.
[8] Cheng X F, Leng W H, Liu D P, et al. Electrochemical preparation and characterization of surface-fluorinated TiO2 nanoporous film and its enhanced photoelectrochemical and photocatalytic properties[J]. Journal of Physical Chemistry C, 2008, 112(23): 8725-8734.
[9] Barnes P R F, Anderson A Y, Durrant J R, et al. Simulation and measurement of complete dye sensitised solar cells: Including the influence of trapping, electrolyte, oxidised dyes and light intensity on steady state and transient device behaviour[J]. Physical Chemistry Chemical Physics, 2011, 13(13): 5798-5816.
[10] Leng W H, Zhang Z, Cheng S A, et al. Estimation of photoelectrocatalytic activity of titanium oxide film electrodes by ac impedance[J]. Chinese Chemical Letters, 2001, 12(11): 1019-1022.
[11] Fei H, Leng W, Li X, et al. Photocatalytic oxidation of arsenite over TiO2: Is superoxide the main oxidant in normal air-saturated aqueous solutions?[J]. Environmental Science & Technology, 2011, 45(10): 4532-4539.
[12] Leng W, Fei H, Zhang J. Response to comment on "photocatalytic oxidation of arsenite over TiO2: Is superoxide the main oxidant in normal air-saturated aqueous solutions?"[J]. Environmental Science & Technology, 2011, 45(22): 9818-9819.
[13] Leng W H, Li X, Fei H, et al. Comment on "photocatalytic oxidation mechanism of as(III) on TiO2: Unique role of as(iii) as a charge recombinant species"[J]. Environmental Science & Technology, 2011, 45(5): 2028-2029.
[14] Leng W H, Cheng X F, Zhang J Q, et al. Comment on "photocatalytic oxidation of arsenite on TiO2: Understanding the controversial oxidation mechanism involving superoxides and the effect of alternative electron acceptors"[J]. Environmental Science & Technology, 2007, 41(17): 6311-6312.
[15] Li X, Leng W. Highly enhanced dye sensitized photocatalytic oxidation of arsenite over TiO2 under visible light by I? as an electron relay[J]. Electrochemistry Communictions, 2012, 22(0): 185-188.
[16] Li X, Leng W. Regenerated dye-sensitized photocatalytic oxidation of arsenite over nanostructured TiO2 films under visible light in normal aqueous solutions: An insight into the mechanism by simultaneous (photo)electrochemical measurements[J]. Journal of Physical Chemistry C, 2013, 117(2): 750-762.