Boosting the photocatalytic activity of β-FeOOH catalyst for toluene oxidation by constructing internal electric field at 0D/1D homojunction interfaces

Abstract

Photocatalytic degradation is considered as the most energy-efficient, environmentally benign, and effective method for treating low fraction organic contaminants. However, the photocatalysts still suffer from low utilization efficiency of visible-light and severe carrier recombination. Heterojunctions can resolve these two main problems in some extent but still be restrained by the low quality of hetero-interface. In this study, homojunction was constructed of β-FeOOH quantum dots and nanorods with the same lattice by a two-step precipitation method, to avoid the heterointerface with too many defects and possess good charge separation as a consequence. The catalysts were characterized by activity test, electron spin resonance, Mott-Schottky plots, photocurrent density tests and open-circuit potential measurements, etc. The results revealed that a strong internal electric fields (IEFs) was created at the interface of catalyst. Beneficently, the electron rearrangement leads to a more rational distribution of oxygen vacancies in the catalyst, resulting in more efficient dissociation of oxygen molecules and formation of active radicals, thus facilitating the efficient degradation of toluene. This study proposes a novel strategy to boosting the photocatalytic activity of low dimensional semiconductors via forming homojunction interfaces to improve their charge transfer.

Keywords: FeOOH; Internal electric field; Photocatalysis; Quantum dots/nano rods; Toluene oxidation.