Construction of α-Bi 2 O 3 /α-Bi 2 O 3 homojunction for highly efficient photocatalytic reduction of (VI)

Abstract

A α-Bi 2 O 3 /α-Bi 2 O 3 homojunction composing of α-Bi 2 O 3 nanosheets growing on α-Bi 2 O 3 nanorods is developed by a facile room-temperature preparation method, which exhibits significantly high photocatalytic performance for reducing heavy metal Cr (VI). The degradation of 50 Cr (VI) solution under simulated sunlight takes only 6 min, and apparent rate constant value reaches 0.657 min -1 which is 9.5 times of α-Bi 2 O 3 nanorods. Photocurrent time curves and electrochemical impedance spectroscopy (EIS) and PL emission spectra prove that the formation of α-Bi 2 O 3 /α-Bi 2 O 3 homojunction improve the transfer and separation of photogenerated e-h pairs.The average fluorescent lifetime of α-Bi 2 O 3 /α-Bi 2 O 3 homojunction is 5.1998 ns which is longer than that of pure α-Bi 2 O 3 . The results of in-situ irradiated X-ray photoelectron spectroscopy (ex-XPS) and the KPFM-based surface photovoltage (SPV) prove that the photoelectrons transfer from α-Bi 2 O 3 nanorod to α-Bi 2 O 3 nanosheet via interface in light. These findings provide a general and simple synthetic method for preparing homojunction photocatalyst, which has a good potential for broad applications.