Preparation of 0D/2D ZnFe2O4/Fe-doped g-C3N4 hybrid photocatalysts for visible light N-2 fixation

摘要

A photocatalyst which consists of zero-dimension (0D) ZnFe2O4 (ZFO) and two-dimension (2D) Fe-doped g-C3N4 (Fe-CN) has been prepared successfully through a facile solvothermal method. The Fe doping into g-C3N4 lattice has been identified by both the infrared (IR) and X-ray photoelectron spectra (XPS), respectively. Introducing Fe into CN extends the spectral response to 700 nm while ZFO serves as a near infrared (NIR) photosensitizer of the Fe-CN component. The formation of Fe-CN heterostructure not only contributes to visible light absorption but also promotes the separation of photo-generated electron-hole pairs. Furthermore, the density functional theory (DFT) calculation indicated that the N-2 molecules prefer to be adsorbed onto the Fe sites with a reduced potential barrier for N-2 fixation. More importantly, the Fe atoms doped into the CN lattice acted as the reaction sites for accelerating photocatalytic N-2 fixation reaction, which was also demonstrated by DFT. These factors lead to a high photocatalytic NH4+ generation rate of 25.3 mg g(-1) h(-1) under a full-spectrum irradiation, which is much higher than the value (4.4 mg g(-1) h(-1)) of pure CN catalysts. This research might provide a novel approach for rationally designing full-spectrum-response N-2 fixation photocatalyst. (C) 2021 Elsevier B.V. All rights reserved.