Nanocomposites and nanomaterials

Polyaniline-TiO2 for application in photocatalytic
phenol degradation

Zahornyi M.N.1, Ragulya A.V.1, Zhygotsky A.G.1, Lobunets T.F. 1,
Ghazzal M.N. 2, Colbeau-Justin C. 2, Bahry T. 2, Remita H.2

1 Institute for Problems of Materials of Science of the NAS of Ukraine.
3, Krzhyzhanovsky Str, E-mail: m.zahornyi@gmail.com
2 Laboratoire de Chimie-Physique CNRS UMR 8000 University PariS Sud
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Photocatalyst involving conducting polymer doped with TiO2 (anatase, anatase-rutile) hold a great efficiency for photocatalytic application [1-2]. In present study, polyaniline (PANI) has been successfully synthesized on surface of modified TiO2 nanoparticles. For TiO2 intensively band absorbance in short wave numbers UV region. For pure conductive polymer two intensive bands especially in the region visible of 550-600 nm (polymer have conjugated system bonds). The band absorbance at 402-420 nm is due to polaron-π* transition in polyaniline. Pure PANI presents characteristic band at 350-415, 550-600 nm So doped PANI has high absorption either in the visible-light region. However, in PANI-TiO2 peak at the region of 500-550 nm disappears and is replaced by a broad and strong absorption band in the visible-light region. 
Photocatalytic activity of PANI-TiO2 nanocomposites were examined by degrading phenol concentration of 50 mg L-1 under UV and visible light irradiation using Xe lamp (300W). Results have been shown that tester phenol degradation occurred firstly 10-20 min, constant rate k is 1·10-2-3·10-2 min-1 for systems with P25 in comparison with anatase systems 8.9·10-4-1.4·10-2 min-1. PANI-TiO2 have been shown the better degradation of phenol than pure TiO2 under visible light irradiation (λ=420 nm). Due to synergistic effect between PANI and TiO2, it is capable of absorbing visible light more efficiently and decreasing the process of electron hole recombination. Spectral analysis proved low efficiency of electron hole recombination of PANI-TiO2.
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1.	Gnanaprakasam A et al. Influencing parameters in the photocatalytic degradation of organic effluent via nanometal oxide catalyst. // J. Mater. Sci.-2015.-2015.-P. 1-16.
2.	Zahornyi M. Functional nanocomposites based of titanium dioxide // Monograph LAP Lambert Academic Publishing, 2018, P. 157 (ISBN: 978-613-8-27486-5)