Highly photoactive Au-TiO^sub 2^ nanowires for improved photo-degradation of propiconazole fungicide under UV/sunlight irradiation

Lengthy TiO^sub 2^ nanostructures exhibiting improved physicochemical properties have been recently investigated for many useful applications. In this context, elongated TiO^sub 2^ nanowires (TNW) of length 1.9-8 μm; diameter 80-270 nm are prepared and 1 wt% Au was photodeposited onto TNW for enhanc...

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Bibliographic Details
Published in:Solar energy 2017-03, Vol.144, p.612
Main Authors: Grover, Inderpreet Singh, Prajapat, Roop Chand, Singh, Satnam, Pal, Bonamali
Format: Article
Language:English
Subjects:
Nanowires
Pesticides
Photocatalysis
Photodegradation
Titanium catalysts
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Summary:Lengthy TiO^sub 2^ nanostructures exhibiting improved physicochemical properties have been recently investigated for many useful applications. In this context, elongated TiO^sub 2^ nanowires (TNW) of length 1.9-8 μm; diameter 80-270 nm are prepared and 1 wt% Au was photodeposited onto TNW for enhanced photo-degradation of propiconazole fungicide under UV/visible light irradiation. The phase composition of TNW (anatase = 72%, rutile = 28%) was almost similar to commercially available P25 TiO^sub 2^ (anatase = 70%, rutile = 30%). TEM analysis reveals uniform dispersion of spherical Au nanoparticles (3-5 nm) deposits over entire TNW surface. The specific surface area 148 m^sup 2^ g^sup -1^ of TNW is notably higher than 59 m^sup 2^ g^sup -1^ of P25 TiO^sub 2^ which is reduced slightly to 136 m^sup 2^ g^sup -1^ after Au loading. TNW exhibited increased (45-64 μs) relaxation time of photoexcited e^sup -^/h^sup +^ pairs as compared to P25 TiO^sub 2^ due to its elongated structure and after Au loading further improves the charge separation efficiency (79 μs). The complete photodecomposition of propiconazole to CO^sub 2^ by bare and Au-loaded TNW under light irradiation through formation of various intermediate products was monitored through HPLC, GC and GC-MS analysis. It revealed that Au-loaded TNW always exhibited 3.5-40 times higher photocatalytic activity than mostly used P25 TiO^sub 2^ because of more anatase phase, larger specific surface area and a higher lifetime of excited charge species where Au loading enhanced the visible light absorption capacity due to surface plasmon interaction.
ISSN:0038-092X
1471-1257
DOI:10.1016/j.solener.2017.02.001