Oxygen vacancy activated inlaid Fe active sites in WO3 for sustainable and efficient photo-Fenton oxidation in a wide pH range

Abstract

The efficient and sustaining activation of Fe sites is of great importance for the heterogeneous photo-Fenton system. Here, through a simple doping strategy, the active Fe centers have been introduced into oxygen vacancy-rich WO₃ nanoplates. The Fe sites were activated by the electron transferring from W atom to Fe sites because of oxygen vacancies association between W and Fe in the photo-excitation process. The directional transport of electrons not only promoted the regeneration of Fe²⁺ to continuously activate the photo-Fenton system, but also promoted the transfer of the photogenerated charge carriers. In addition, the results of the DFT calculations prove that the doping of Fe in turn helps the stability of the oxygen vacancy. As a result, the optimized Fe–WO₃–0.75 sample exhibited a kinetic rate of 0.0424 min^-1 in the degradation of tetracycline hydrochloride. This rate is more than three times higher than that of WO₃ (0.0137 min^-1). The Fe–WO₃ catalyst exhibited a good stability and a wide range of adaptability of pH values by taking advantage of the synergy of Fe sites and oxygen vacancy, which indicates the practical potentials for environmental applications.