Hydrophobic Functionalization of ZnO Nanosheets by In Situ Center‐Substituted Synthesis for Selective Photocatalysis under Visible Irradiation

Abstract

AbstractThe selective degradation of specific substances in mixed contaminants is quite challenging. And a general approach for sensitized oxide semiconductor relies on dip‐coating method with sensitizer. Here, hydrophilic 2D, nest‐like architecture ZnO (ZnO NA) was hydrophobicly functioned by monomolecular–layer tetraphenylporphyrin zinc (ZnTPP), where ZnTPP was synthesized by means of an in situ center‐substituted (ISCS) process., i.e., the hydrogen atoms in the core of metal‐free tetraphenylporphyrin (H2TPP) are substituted by the unsaturated zinc ions in ZnO NAs. ZnTPP/ZnO NA was exhibited with significant hydrophobicity, benefitting to absorb hydrophobic phenol (PL). Further, it is realized to selectively photodegradate PL in the mixture by ZnTPP/ZnO NAs under visible irradiation. Note that the rate of degradation to hydrophobic PL by ZnTPP/ZnO NA is 9.17 times of that for ZnO NA within 150 min; on the contrary, the degradation rate of hydrophilic rhodamine B (RhB) by ZnTPP/ZnO is reduced by 40%. Radiative lifetime of photogenerated charges is obviously increased by ZnTPP/ZnO NA compared with that of ZnTPP, indicating the effective charge separation for ZnTPP/ZnO NAs. In addition, ZnTPP/ZnO NA produced more superoxide radicals (·O2−) in comparison to ZnO NA. With surface functionalization, the feasibility of selective photocatalysis under visible irradiation is demonstrated.