Bi₄O₅Br₂ Nanoflower and CdWO₄ Nanorod Heterojunctions for Photocatalytic Synthesis of Ammonia

Abstract

In this study, a Bi 4 O 5 Br 2 /CdWO 4 (BOB/CWO) composite photocatalyst was designed and prepared using a convenient hydrothermal method. A detailed investigation was carried out on the morphology, specific surface area, structure, optical properties, and photoelectric chemical properties of the BOB/CWO composite. The CdWO 4 nanorods were found to disperse on the surface of Bi 4 O 5 Br 2 nanoflowers, and their tight contact between CdWO 4 and Bi 4 O 5 Br 2 resulted in the formation of a heterojunction structure. By analysis of the band structure of the two semiconductors, it was found that the heterojunction worked in a type II mechanism, effectively improving the separation efficiency of electron−hole pairs. Therefore, the BOB/CWO composite exhibited high performance in photocatalytic N 2 fixation (PNF) reactions. The optimal BOB/CWO catalyst presents a PNF rate of 501 μmol L −1 g −1 h −1 under simulated sunlight irradiation, which was 5.7 and 3.1 times that of pure CdWO 4 and Bi 4 O 5 Br 2 , respectively. Under visible-light illumination, the BOB/CWO heterojunction worked in a sensitized mechanism, and the coupling effect of CdWO 4 and Bi 4 O 5 Br 2 in boosting the PNF reaction could still be observed. The findings of this study are anticipated to offer practical knowledge about the design and synthesis of efficient photocatalysts for PNF. KEYWORDS: photocatalytic N 2 fixation, Bi 4 O 5 Br 2 /CdWO 4 , type II, sensitized mechanism, charge separation

Enhanced oxidative degradation of tetracycline by visible light-promoted g-C3N4 modified Cu3(OH)4SO4/Cu7S4 composites under an air atmosphere

“…As expected, the CSG heterojunction presented the lowest charge transport resistance, revealing that the formation of heterojunctions can boost the charge mobility and photogenic electron–hole separation efficiency. 41–43 These results are consistent with the transient photocurrent performance. Besides, Fig.…”

Cu/NiO nanorods for efficiently promoting the electrochemical nitrate reduction to ammonia

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Simultaneous photocatalytic degradation of methylene blue and methyl orange using a green synthesized Zn0.98Mn0.02O/BiOCl nanocomposite

“…8. 60–62 In BiOCl under solar illumination, electrons are also jumped from the VB to the CB, and then holes are also produced. The electrons in the CB of BiOCl move towards the CB of Zn 0.98 Mn 0.02 O to reduce the dissolved oxygen into superoxide anionic radical O 2 ˙ − better as compared to pure samples of Zn 0.98 Mn 0.02 O and BiOCl.…”

“…5 mM of scavengers such as BQ, TBA, AgNO 3 and Na 2 –EDTA were added into the dye solution followed by the addition of the nanocomposite (Zn 0.98 Mn 0.02 O/BiOCl) to trap the superoxide anion radicals (O 2 ˙ − ), hydroxyl radicals (OH˙), electrons (e − ) and holes (h + ), respectively. 59–62 The photodegradation of both the methylene blue and methyl orange dyes was checked under sunlight using the Zn 0.98 Mn 0.02 O/BiOCl nanocomposite in the presence of scavengers. Fig.…”