Facet exposure-dependent photoelectrocatalytic oxidation kinetics of bisphenol A on nanocrystalline {001} TiO2/carbon aerogel electrode

An anatase TiO2 with {001} facet exhibits high oxidation activity towards the degradation of wastewater. The impact of {001} facet exposure degree on the degradation oxidation kinetics and mechanism is still unclear and urgently needs to be discussed. The photoelectrocatalytic (PEC) degradation of bisphenol A (BPA) in wastewater using facet-controlled nanocrystalline {001} TiO2/carbon aerogel (CA) photo electrodes was then investigated in this study. Nano-sized anatase {001} TiO2 crystals with different {001} facet exposure degrees of high (90%), medium (48%) and low (15%) were constructed on a CA substrate via electrophoretic deposition. A positive correlation was found between the {001} facet exposure and the photocurrent density, electron carrier concentration and the total amount of OH. Nearly 100% BPA removal efficiency was shown on the 90%-{001}TiO2/CA in 6h. The rate constant (k) value was 0.454 h-1 and the TOC rate was 83%. They are 1.8 and 1.8 times greater than those obtained on the 48%-{001}TiO2/CA, as well as 3.5 and 2.4 times greater than those on the 15%-{001}TiO2/CA, respectively. The greatly promoted PEC oxidation activity of 90%-{001}TiO2/CA is due to its more rapidly accumulated intermediates products than other two photoelectrodes, which then completely mineralize into CO2 and H20. This is mainly because of the highest oxidation sites existed on the 90%-{001}TiO2 surface and the efficient separation of electron-hole pairs between the {001} TiO2 and CA under the electric fields. (C) 2017 Elsevier B.V. All rights reserved.