Corresponding Author

Aicheng Chen(aicheng.chen@lakeheadu.ca)


In this study, TiO2 nanotubes were prepared via the electrochemical oxidation of titanium substrates in a non-aqueous electrolyte and their morphology and microstructures were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photoelectrochemical oxidation of two lignin model compounds, 1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanediol (DMP) and 3-hydroxy-1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanone (HDM), was investigated. A new band appeared at ~304 nm during the photoelectrochemical oxidation of DMP. The rate of DMP intermediate formation was amplified with the increase of initial concentrations, while it was diminished with increased temperature. Despite the similarity in structure between HDM and DMP, there are only small increases in absorbance during the oxidation of HDM, suggesting that HDM is less reactive. Quantum chemical calculations based on the density functional theory (DFT) were performed in order to link photoelectrochemical reactivity with specific molecular properties. Relatively higher ELUMO-EHOMO of HDM makes it more stable and thus more refractory to oxidation, which is consistent with our photoelectrochemical results.

Graphical Abstract


Photoelectrochemical oxidation, TiO2 nanotubes, UV-Vis spectroscopy, lignin model compounds, DFT calculation

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[1] Wu D, Shi Q C, Zhou J T, et al. Deep treatment of pulping wastewater using three phase fluidized bed electrode reactor[J]. Journal of Electrochemistry, 2006, 12(4): 412-415.

[2] Pan K, Tian M, Jiang Z H, et al. Electrochemical oxidation of lignin at lead dioxide nanoparticles photoelectrodeposited on TiO2 nanotube arrays[J], Electrochimica Acta, 2012, 60: 147-153.

[3] Tian M, Bakovic L, Chen A. Kinetics of the electrochemical oxidation of 2-nitrophenol and 4-nitrophenol studied by in situ UV spectroscopy and chemometrics[J]. Electrochimica Acta, 2007, 52(23): 6517-6524.

[4] Li T C, Zhu S L. Research on phenol wastewater treatment by electrochemical oxidation[J]. Journal of Electrochemistry, 2005, 11(1): 101-104.

[5] Wang B C, Sun Y P. Adsorption and oxidation of phenol electrode processes[J]. Journal of Electrochemistry, 2003, 9(4): 475-478.

[6] O’Connor O A, Young L Y. Toxicity and anaerobic biodegradability of substituted phenols under methanogenic conditions[J]. Environmental Toxicology and Chemistry, 1989, 8(10): 853-862.

[7] Tian M, Wen J L, MacDonald D, et al. A novel approach to convert lignin into value-added products [J], Electrochemistry Communications, 2010, 12(4): 527-530.

[8] Liu Y, Liu D, Zhao S L, et al .Electrochemical oxidation of the phenol in the chloride system[J]. Journal of Electrochemistry, 2007, 13(1): 30-34.

[9] Li Z F, Electrochemical disinfection method to treat wastewater from hospitals[J]. Journal of Electrochemistry, 2005, 11(4): 420-424.

[10] Tolba R, Tian M, Wen J L, et al. Electrochemical oxidation/modification of lignin at IrO2-based mixed oxide electrodes[J]. Journal of Electroanalytical Chemistry, 2010, 649(1/2): 9-16.

[11] Cao B, Xu J W, Ding L H, et al. Preparation and electrochemical characterization of anatase TiO2 nanotubes[J]. Journal of Electrochemistry, 2006, 12(4): 445-448.

[12] Lan B B, Zhou J Z, Xi Y Y, et al. Special Photoelectrochemical response of nano-crystalline TiO2 electrode[J]. Journal of Electrochemistry, 2006, 12(1): 16-19.

[13] Tian M, Thind S S, Chen S, et al. Significant enhancement of the photoelectrochemical activity of TiO2 nanotubes[J]. Electrochemistry Communications, 2011, 13(11): 1186-1189.

[14] Egerton T A, Christensen P A, Harrison R W, et al. The effect of UV absorption on the photocatalytic oxidation of 2-nitrophenol and 4-nitrophenol[J]. Jouranal of Applied Electrochemistry, 2005, 35(7/8): 799-813.

[15] Tian M, Adams B, Wen J L, et al. Photoelectrochemical oxidation of salicyclic acid and salicylaldehyde on titanium dioxide nanotube arrays[J]. Electrochimica Acta, 2009, 54(14): 3799-3805.

[16] Yang S M, Wang J C, Kou H Z, et al. Influence of tert-butylpyridine on the band energetics of nanostructured TiO2 electrodes and the photoelectrochemical properties of dye-sensitized electrodes[J]. Journal of Electrochemistry, 2011, 17(2): 204-211.

[17] Yun H, Lin C J, Li J, et al. Photoelectrochemical properties of N, S, and Cl modified nano TiO2 thin Films[J]. Journal of Electrochemistry, 2010, 16(4): 411-415A.

[18] Zhang Y H, Zhang H X, Xu Y X, at al. Significant effect of lanthanide doping on the texture and properties of nanocrystalline mesoporous TiO2[J]. Journal of Solid State Chemistry, 2004, 177(10): 3490-3498.

[19] Wu P F, Li M C, Shen J N, et al. Preparation of photo-electrochemical anticorrosion TiO2 films by anodization method[J]. Journal of Electrochemistry, 2004, 10(3): 353-358.

[20] Wu G, Wen J, Nigro S, et al. One-step synthesis of N&F co-doped mesoporous TiO2 photocatalysts with high visible light activity[J]. Nanotechnology, 2010, 21: 085701/1 – 6.

[21] Shibata T, Sakai N, Fukuda K, et al. Photocatalytic properties of titania nanostructured films fabricated from titania nanosheets[J]. Physical Chemistry Chemical Physics, 2007, 9(19): 2413.

[22] Wu G, Chen A. Direct growth of F-doped TiO2 particulate thin films with high photocatalytic activity for environmental applications[J], Journal of Photochemistry and Photobiology A: Chemistry, 2008, 195: 47 – 53.

[23] Antunes C S A, Bitti M, Salamone M, et al. Early stages in the TiO2-photocatalyzed degradation of simple phenolic and non-phenolic lignin model compounds[J]. Journal of Photochemistry and Photobiology A: Chemistry, 2004, 163(3): 453-462.

[24] Ruggiero R, Machado A E H, Castellan A, et al. Photoreactivity of lignin model compounds in the photobleaching of chemical pulps.1. Irradiation of 1-(3,4-dimethoxyphenyl)-2-(3'-methoxyphenoxy) -1,3-dihydroxypropane in the presence of singlet oxygen sensitizer or hydrogen peroxide in basic methanol solution[J]. Journal of Photochemistry and Photobiology A: Chemistry, 1997, 110(1): 91-97.

[25] Chen A, Rogers E, Compton R G. Abrasive stripping voltammetric studies of lignin and lignin model compounds[J]. Electroanalysis, 2010, 22: 1037–1044.

[26] Zhang S G, Lei W, Xia M Z, et al. QSAR study on N-containing corrosion inhibitors: Quantum chemical approach assisted by topological index[J]. Journal of Molecular Structure, 2005, 732(1/3): 173-182.

[27] Lashgari M, Arshadi M R, Parsafar G A. A simple and fast method for comparison of corrosion inhibition powers between pairs of pyridine derivative molecules[J]. Corrosion, 2005, 61(8): 778-783.

[28] Fujishima A, Honda K. Electrochemical photolysis of water at a semiconductor electrode[J]. Nature, 1972, 238(5358): 37-38.

[29] Zlamal M, Macak J M, Schmuki P, et al. Electrochemically assisted photocatalysis on self-organized TiO2 nanotubes[J]. Electrochemistry Communications, 2007, 9(12): 2822-2826.

[30] Vinodgopal K, Stafford U, Gray K A et al. Electrochemically assisted photocatalysis. 2. The role of oxygen and reaction intermediates in the degradation of 4-chlorophenol on immobilized TiO2 particulate films[J]. Journal of Physical Chemistry, 1994, 98(27): 6797-6803.

[31] Schmidt J A, Heitner C. Light-induced yellowing of mechanical and ultra-high-yield pulps. 2. Radical-induced cleavage of etherified gualacylglycero-beta-arylether groups is the main degradative pathway[J]. Journal of Wood Chemistry Technology, 1993, 13(3): 309-325.

[32] Al-Ekabi H, Serpone N., Kinetics studies in heterogeneous photocatalysis. 1 photocatalytic degradation of chlorinated phenols in aerated aqueous solutions over TiO2 supported on a glass matrix[J]. Journal of Physical Chemistry, 1988, 92(20): 5726-5731.

[33] Matthews R W. Kinetics of photocatalytic oxidation of organic solutes over titanium-dioxide[J]. Journal of Catalysis, 1988, 111(2): 264-272.

[34] Matthews R W. Photooxidation of organic impurities in water using thin-films of titanium-dioxide[J]. Journal of Physical Chemistry, 1987, 91(12): 3328-3333.

[35] Chen D W, Ray A K. Photodegradation kinetics of 4-nitrophenol in TiO2 suspension[J]. Water Research, 1998, 323(11): 3223-3234.

[36] Bachrach S M. Computational organic chemistry[M]. John Wiley & Sons, 2007.

[37] Tian M, Thind S, Simko M, et al. Quantitative structure-reactivity study of electrochemical oxidation of phenolic compounds at the SnO2-based electrode[J]. Journal of Physical Chemistry A, 2012, 116: 2927-2934..

[38] Pearson R G, Electronic spectra and chemical reactivity[J]. Journal of the American Chemical Society, 1988, 110(7): 2092-2097.

[39] Szwacki N G, Sadrzadeh A, Yakobson B I. B-80 fullerene: An ab initio prediction of geometry, stability, and electronic structure[J]. Physical Review Letters, 2007, 98(16):166804.



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