Abstract
In this study, TiO2 nanotubes (TiNTs) co-modified with MnOx (Mn) and reduced-graphene-oxide (RGO) were prepared by a simple electrochemical deposition process. The photocatalytic activities for reducing CO2 and degradating 2,4-dichlorophenol of TiNTs were enhanced after co-modification with proper amounts of MnOx and RGO. The yields of acetic acid and formic acid of the amount-optimized TiNTs (6RGO/4Mn/TiNTs) were 36.3 ± 0.9 and 21.6 ± 0.7 mg L-1 h-1, which were ∼2.5 times and ∼2.2 times of bare TiNTs and the 2,4-dichlorophenol degradation efficiency of 6RGO/4Mn/TiNTs was 36.9% for 1 h, which was 21.3% higher than bare TiNTs. According to the results of photophysical and photochemical experiments, the enhanced photocatalytic activity was attributed to the greatly-elevated photogenerated charge separation via the bi-directional control mechanism of electrons and holes. The photogenerated holes could be captured by MnOx and the transfer of photogenerated electrons could be accelerated through the RGO. In addition, the formed OH was found to act as major active species in the 2,4-dichlorophenol degradation process. The degradation paths by OH attacking was proposed by analyzing the main intermediates.
Published Version
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