In this study, a new type of 2D/2D Bi 2 O 3−x /NiAl-LDH (BO/NA-LDH) S-scheme photocatalyst was prepared by combining NiAl-LDH with Bi 2 O 3−x by wet chemical deposition for obtaining efficient photothermal-assisted photocatalytic reduction of CO 2 under simulated sunlight irradiation. In particular, the as-prepared optimal 50-BO/NA-LDH sample exhibited the CO production yield of 83.55 ± 2.76 μmol/g/h, which was 9 and 27 times that of BO (9.32 ± 0.62 μmol/g/h) and NA-LDH (3.09 ± 0.38 μmol/g/h), respectively. The enhancement of photothermal-assisted activity over the 50-BO/NA-LDH system was mainly attributed to the coupling of the photothermal conversion performance of Bi 2 O 3−x and improving the migration efficiency of interface carriers of S-scheme heterojunction and 2D/2D structure. This study presents a promising strategy for the development of high-efficient photothermal-assisted photocatalysts.
Bismuth-based photocatalysts are a class of excellent visible-light photocatalysts; however, their redox activity is relatively poor and the efficiency of photogenerated carrier separation is low, limiting their development and application in the field of photocatalysis . To address these issues, a series of polyoxometalate PW 12 O 40 3– -doped Bi 2 O 3– x /Bi Schottky photocatalysts PW 12 @Bi 2 O 3– x /Bi- n (PBOB- n , where n is the amount of NaBH 4 , i.e., 6, 12, 18, 24, and 48 mg) were prepared by a simple electrospinning/calcination/in-situ NaBH 4 reduction method. In this composite photocatalyst, the doping of PW 12 could effectively adjust the electronic structure of Bi 2 O 3– x and improve its redox properties. As a shallow electron trap, PW 12 promoted the separation of the photogenerated carriers. Furthermore, desirable Schottky junction between the metal Bi nanoparticles and PW 12 @Bi 2 O 3– x further accelerated the separation of the photogenerated carriers. The synergistic effect of the aforementioned factors endowed PBOB- n with excellent photocatalytic activity. Among the samples, PBOB-18 exhibited superior photocatalytic activity. Under visible-light irradiation, 93.7% (20 mg catalyst) of 20 ppm tetrabromobisphenol A (TBBPA, 20 mL) was degraded in 60 min. Its activity was 4.4 times higher than that of Bi 2 O 3 . PBOB-18 also exhibited an ultrahigh photocatalytic performance for the removal of NO. Its removal rate (600 ppb) reached 83.3% in 30 min, making it one of the most active Bi-based photocatalysts. Furthermore, the photocatalytic mechanisms of PBOB-18 for TBBPA and NO have been proposed. This work provides a new direction and reference for the design of low-cost, efficient, stable, and versatile photocatalysts.
Novel black oxygen deficient bismuth oxide (Bi 2 O 3 -Bi 2 O 3 – x ) photocatalytic material was successfully prepared by a two zone temperature controlled muffle furnace method. The lanthanum , cerium and erbium ions are successfully doped into Bi 2 O 3 -Bi 2 O 3 – x with the average contents of 10.77 wt%, 7.62 wt% and 8.14 wt%, respectively. The results show that a large number of oxygen vacancies exist in Bi 2 O 3 -Bi 2 O 3 – x . La 3+ , Ce 3+ and Er 3+ act as electron acceptors to temporarily trap the photo-generated electrons. The XPS spectrum show Bi-O band in Bi 2 O 3 -Bi 2 O 3 – x and the O 1s peak of Ce/Bi 2 O 3 -Bi 2 O 3 – x move toward the direction of low binding energy. These phenomena fully prove that the separation of photogenerated electron-hole pairs will be more effectual, so as to reduce the possibility of charge carrier recombination. The radical scavenging experiments and electron spin resonance detections confirm that the conduction band of the original Bi 2 O 3 can easily receive photogenerated electrons, while the valence band of the modified Bi 2 O 3 -Bi 2 O 3 – x tends to accept photogenerated holes and then forms the circulation system. Therefore, Ce/Bi 2 O 3 -Bi 2 O 3 – x can degrade tetracycline hydrochloride up to 90.15%. This research provides some new insights into developing green and recyclable photocatalysts for the remediation of antibiotic contamination.
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