Construction of Eu2O3/g‐C3N4 Redox Heterojunctions Containing Eu3+/Eu2+ Self‐Redox Centers for Boosted Visible‐Light Photocatalytic Activity

Abstract

The in‐built self‐redox couple in a heterojunction can indeed boost its photocatalytic activity. Herein, to obtain highly efficient visible‐light photocatalysis, a new Eu2O3/g‐C3N4 redox heterojunction is designed and fabricated by a facile in situ growth strategy. Compared with pure g‐C3N4, the as‐prepared Eu2O3/g‐C3N4 redox heterojunction shows extremely enhanced photocatalytic performance for the decontamination of organic contaminants under visible‐light irradiation. The presence of the Eu3+/Eu2+ self‐redox couple is identified by X‐ray photoelectron spectroscopy spectra analysis, before and after photoreaction. The boosted photocatalytic mechanism is explored systematically through UV/Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and photocurrent measurements. Moreover, the radical trapping and electron paramagnetic resonance experiments reveal that ·O2– and h+ are the main active species, and a small amount of ·OH radical is also generated. The boosted photocatalytic performance is derived from the effective separation of photogenerated e–/h+ pairs by forming a Eu2O3/g‐C3N4 heterostructure with a self‐redox center. In particular, the self‐redox couple of Eu3+/Eu2+ can lead to more effective separation of the photogenerated charge carriers, as well as to sustainable production of ·O2–. It is anticipated that our study could provide new insight into the development of g‐C3N4‐based redox heterojunctions with high visible‐light photocatalytic performance.