Photoelectrocatalytic activity of highly ordered TiO nanotube arrays modified with polyaniline for tetrabromobisphenol A degradation in water.

Polyaniline (PANI) is a useful conductive polymer material, and has good adsorption property, which makes it a good modification material. In this work, for the sake of highly enhancing the utilization of visible region in sunlight and accelerating photocatalytic degradation of tetrabromobisphenol A (TBBPA), a typical polybrominated flame retardant, titanium dioxide nanotube arrays (TiO NTAs) were modified with PANI by chemical and electrochemical polymerization. The coated amount of PANI was controlled via adjusting the polymerization time and the amount of aniline in the electrochemical method. The results demonstrate that the EC-PANI/TiO NTAs (synthesized electrochemically) exhibit higher catalytic activity than bare TiO NTAs and C-PANI/TiO NTAs (synthesized chemically) in photoelectrocatalytic degradation of TBBPA under visible light, and the degradation efficiency for TBBPA could reach 94.37% within 120 min. The improved performance was contributed to the synergetic effect of PANI modification which integrated the broad absorption of PANI in visible light region and high catalytic property of TiO NTAs. Interestingly, it was also found that the degradation efficiency of TBBPA by EC-PANI/TiO was further enhanced by up to 95.74% when the ethanol was present in the reaction system as the hole scavenger. Furthermore, the EC-PANI/TiO exhibited excellent stability after 10 cycling experiments. All the results indicated that this new modified material presented strong potential as a photoelectrocatalyst and had great practical applications in the future.