Selective photoelectrocatalytic removal of environmental pollutants on molecular imprints decorated TiO2 single crystalline nanoarrays

Abstract

Degradation of environmental pollutants is of great importance, while selective removal of toxic contaminants from complicated and neutral environmental samples still remains as a big challenge. Herein, a two-dimensional photoelectrocatalyst is fabricated through decorating (0 0 1) facet oriented and homogenous TiO2 single crystalline nanoarrays with uniform molecular imprints. As confirmed from in situ Raman and in situ IR spectroelectrochemical measurements, this system displays high specificity towards 2,4-dichlorophenoxyacetic acid, instead of other substances co-existed in the environmental samples. The concentration of selectively adsorbed 2,4-dichlorophenoxyacetic acid is as high as 1.08 × 10−9 mol cm−2 mg−1. Together with superior photoelectrocatalytic oxidation ability of these vertically aligned TiO2 single crystalline nanoarrays, selective and efficient removal of 2,4-dichlorophenoxyacetic acid into carbon dioxide and water is achieved in complex and neutral environmental samples. With a degradation time of 3 h and a potential of 2 V, its removal ratio reaches almost 100%. In general, the proposed strategy provides a way to construct and utilize novel photoelectrocatalysts for the realization of both efficient and selective removal of defined and toxic pollutants from complicated and neutral environmental samples.