3D CQDs-{001}TiO2/Ti photoelectrode with dominant {001} facets: Efficient visible-light-driven photoelectrocatalytic oxidation of organic pollutants and mechanism insight

A three dimensional (3D) carbon quantum dots (CQDs) decorated {001}TiO2/Ti photoelectrode was prepared by constructing the CQDs on the surface of {001} TiO2, which were grown in-situ on Ti-mesh structure, providing the nearly 100% exposed active {001} facets. The 3D CQDs-{001}TiO2/Ti shows high PEC oxidation activity towards the MO and BPA under visible light radiation, while the relevant removal ratios are 94.8% for BPA in 1 h and 93.6% for MO in 2 h, respectively. The enhanced PEC activity of CQDs-{001}TiO2/Ti is mainly attributed to the three improved factors (eta(abs), eta(sep) and eta(inj)), which is analyzed deeply. The existence of CQDs not only improve the eta(abs) since its superior up-conversion performance, but also promote the higher eta(sep) due to enhanced hole-electron pairs' separation. The highly exposed {001} facets are favorable for oxidation reactions to provide the increased eta(inj).