Effective 1D/2D nanostructured S-scheme W18O49/g-C3N4 heterojunction photocatalyst fabrication for improved photocatalytic nitrogen fixation performance

Abstract

The fundamental insights into the reaction mechanism, especially the electron transfer mechanism, are highly promising yet challenging for W18O49/g-C3N4 heterojunction catalysts during photocatalytic nitrogen fixation. Herein, the 1D/2D nanostructured S-scheme heterojunctions were designed by in situ growth of 1D W18O49 nanowires on 2D g-C3N4 nanosheets through solvothermal method using methanol as solvent. In situ XPS analysis revealed that electrons in the conduction band of W18O49 recombine with holes in the valence band of g-C3N4 under the conduction effect of internal electric field, band bending, and Coulombic attraction in the W18O49/g-C3N4 heterojunction. The photogenerated electrons are retained in g-C3N4, where the negative reduction potential of its conduction band enhances the activation of N2. As a result, the ammonia generation rate employing the optimal W18O49/g-C3N4 heterojunction is 64.8 μmol gcat−1 h−1, approximately double that of W18O49 alone and 2.3 times higher than that of g-C3N4. The enhanced activity and facile methodology make the current material exceedingly appealing for implementation in photocatalytic nitrogen fixation for the synthesis of ammonia.