Highly Efficient Degradation of Persistent Pollutants with 3D Nanocone TiO2-Based Photoelectrocatalysis

Photoelectrocatalytic (PEC) degradation of organic pollutants into CO2 and H2O is a promising strategy for addressing ever-growing environmental problems. Titanium dioxide (TiO2) has been widely studied because of its good performance and environmental benignancy; however, the PEC activity of TiO2 catalyst is substantially limited due to its fast electron–hole recombination. Herein, we report a TiO2 nanocone-based photoelectrocatalyst with superior degradation performance and outstanding durability. The unique conical catalyst can boost the PEC degradation of 4-chlorophenol (4-CP) with 99% degradation efficiency and higher than 55% mineralization efficiency at a concentration of 20 ppm. The normalized apparent rate constant of a nanocone catalyst is 5.05 h–1 g–1 m2, which is 3 times that of a nanorod catalyst and 6 times that of an aggregated particle catalyst, respectively. Further characterizations reveal that the conical morphology of TiO2 can make photogenerated charges separate and transfer more efficiently, resulting in outstanding PEC activity. Moreover, computational fluid dynamics simulations indicate that a three-dimensional conical structure is beneficial for mass transfer. This work highlights that tuning the morphology of a photoelectrocatalyst at the nanometer scale not only promotes the charge transfer but also facilitates the mass transportation, which jointly enhance the PEC performance in the degradation of persistent pollutants.