Topology engineering of UiO-66@TiO2-based photoelectrocatalyst for highly efficient degradation of binary pollutants

Photoelectrocatalysis (PEC) is an efficient strategy for addressing organic pollutants in the environmental water system. Titanium dioxide (TiO2) based composite photoelectrodes have been widely researched due to excellent photocatalytic performance and chemical durability. However, light transmission and mass transport at the active sites inside photoelectrode are substantially limited because of topological irrationality. Herein, topology engineering of UiO-66@TiO2-based photoelectrocatalyst is presented to overcome this disadvantage. Compared to the edge-structure of cubic UiO-66 wrapped TNFs (CU@T/T), center-structure of octahedral UiO-66 embedded TNFs (OU@T/T) can enhance the light capture capability and mass transport, and then improve the PEC activity. Simultaneously photoelectrocatalytic degradation of RhB and MO also shows that topologically optimized OU@T/T exhibits excellent catalytic activity and durability. At 2.0 V of bias potential, RhB and MO (both 5 mg/L) can be almost completely removed at 200 min (99.06 % and 98.81 %) in the solution with 7.0 of pH under the action of active species (⋅O2– and ⋅OH), and no attenuation after five cycles. This work highlights that topology engineering of UiO-66@TiO2-based photoelectrocatalyst not only facilitates charge transfer but also promotes mass transport, which greatly improves the PEC degradation performance of binary pollutants.