Boosting Photocatalytic Nitrogen Fixation via In Situ Constructing Bi Metal Active Sites over BiOBr/BiOI Heterojunction

Abstract

The main obstacles to the photocatalytic reduction of nitrogen are the low separation efficiency of photogenerated charges and the few activation sites for nitrogen. It is highly desirable to explore new strategies for improving the nitrogen fixation performance of catalysts. Herein, the Bi metal active sites are constructed on the surface of BiOBr/BiOI heterojunction by in situ reaction, which promote the absorption, activation, and dissociation of nitrogen molecules. Moreover, the existence of Bi metal and BiOBr/BiOI heterojunction enhances the light absorption ability and facilitates the separation and transfer of photogenerated charges. The theoretical calculation also demonstrates that the BiOBr/BiOI/Bi composite has excellent electron structure and electron transfer efficiency. So, the ternary BiOBr/BiOI/Bi catalyst shows excellent performance of photocatalytic reduction of nitrogen to ammonia. The nitrogen reduction rate is 221.9 μmol g−1 h−1, which is 7.6 and 5 times higher than that of pure BiOBr and BiOBr/BiOI. The mechanism of photocatalytic nitrogen fixation of the BiOBr/BiOI/Bi is proposed based on the experimental and theoretical results. This study provides a novel method for improving the photocatalytic nitrogen reduction performance of catalysts.

Advances in Photocatalytic Disinfection: Performances and Mechanisms

“…The BiOBr/BiOI/Bi composite has excellent electron‐transfer efficiency, which shows excellent performance of photocatalytic reduction of nitrogen to ammonia, much higher than that of pure BiOBr and BiOBr/BiOI. [ 99 ] Highly ordered mesoporous Ag/CeO 2 nanocomposites exhibited excellent photocatalytic‐disinfection efficiency for E. coli . Doping Ag can expand the absorption range to the visible‐light region.…”

In situ fabrication of S-type BiOI x Br y heterojunction with metallic Bi for boosting photocatalytic activity for CO2 reduction

“…This suggests that efficient photocatalysts require appropriate light trapping capabilities. By introducing Br element to modulate the gap width and construct heterojunction [38], and then the photocatalytic activity of the composite is improved.…”

“…Then, the e − accumulated BiOBr CB tends to re-assemble with the h + of BiOI VB , the band bending and coulomb attraction contributing to this tendency [41,43]. It is well documented that metallic Bi nanoparticles exhibit SPR effects in the region near visible light [31,38,40]. At this time, the in situ generated metallic Bi, can act as a transit station to accept the e − of BiOBr and h + of BiOI to prevent them from flowing back in, followed by the strong oscillating electric field generated by the SPR effect to directly promote the separation of photogenerated charges [44].…”

Zinc-Doped BiOBr Hollow Microspheres for Enhanced Visible Light Photocatalytic Degradation of Antibiotic Residues

“…Among these, BiOBr possesses an appropriate band gap, excellent responsiveness to visible light, and remarkable environmental friendliness. , Consequently, they have emerged as a prominent semiconductor material within the realm of photocatalysis. However, the common issues of semiconductor materials still limit the application of BiOBr. − It is well-known that inorganic nanomaterials with a hollow structure may possess excellent optical properties, good loading and wrapping capability, high dispersion, and cyclic stability and thus have attracted wide attention. For instance, Liu et al synthesized multilayered porous TiO 2 hollow microspheres by a one-step template method and used them for rhodamine B degradation, with an efficiency far superior to that of commercial P25.…”