Enhanced Photodegradation Activity Research Articles

Visible light responsive SiO2/g-C3N4/BiOBr/Bi heterojunction photocatalyst for degradation of rhodamine B

For the purpose of alleviating the negative influence of rhodamine B (RhB) abuse on the environment, it is imperative to design a green and efficient photocatalyst for tackling organic dye-contaminated wastewater. Herein, a novel SiO2/g-C3N4/BiOBr/Bi (denoted as Si/CN/BiOB/Bi) photocatalyst with enhanced photodegradation activity has been successfully created. The influence of variable parameters including Bi doping amount, initial concentration of RhB, photocatalyst dosage, and reaction temperature on the photocatalytic performance of Si/CN/BiOB/Bi under visible light illumination are analyzed in detail. Results indicated that the degradation rate constant of RhB over Si/CN/BiOB/Bi-0.5 is 25.1, 18.1, and 2.2 times higher than that of CN, Si/CN, and Si/CN/BiOB, respectively. The Si/CN/BiOB/Bi-0.5 photocatalyst displayed high photocatalytic performance after 5 recycled runs. The improved photocatalytic performance can be attributed to the novel morphology as well as the excellent synergetic effects of Si/CN, BiOBr, and Bi, which enables the catalysts to accelerate the separation of photogenerated carriers. In brief, a new Si/CN/BiOB/Bi photocatalyst has a great application perspective for the purification of RhB wastewater.

S-scheme Bi/Bi2WO6/TiO2 nanofiber photocatalyst for efficient degradation of sulfamethoxazole

Improving the efficiency of photogenerated carrier separation by designing heterojunction photocatalysts remains an important challenge. In this study, TiO2 nanofibers were prepared by electrospinning, Bi/Bi2WO6/TiO2 heterojunctions were constructed by hydrothermal method, and verified by characterization techniques. The heterojunction had good photodegradation activity to sulfamethoxazole (SMX) under ultraviolet and visible light irradiation (96.4 % within 60 min). The enhanced photodegradation activity of Bi/Bi2WO6/TiO2 nanocomposites can be attributed to the synergistic effect of S-Scheme mechanism and Bi metal plasma action. In addition, Bi metals can generate a large number of electron-hole pairs under the action of surface plasmon resonance (SPR). In addition, the influence factors such as pH, SMX concentration and catalyst loading were studied. According to the detected intermediates, the photocatalytic degradation pathway of SMX was studied. The results of free radical capture experiment and ESR show that ·O2– and h+ free radicals play an important role in the decomposition of SMX. The cyclic experiments show that Bi/Bi2WO6/TiO2 nanocomposites have excellent stability and reuse characteristics. Finally, the mechanism of photocatalytic degradation of SMX was described. This study provides a promising perspective for the preparation and development of S-Scheme heterojunction photocatalysts based on Bi2WO6.

Effortless Fabrication of Bi2O3‐Co3O4 Nanocomposite Catalyst: Harnessing Photocatalytic Power for Efficient Cationic Dye Degradation

AbstractA cost‐effective and simple co‐precipitation approach was used to create an efficient photocatalyst Co3O4‐Bi2O3 with identical stoichiometry (1 : 1 of both Co3O4 and Bi2O3). XRD, FTIR, TEM, SEM‐EDS, XPS, UV‐DRS, PL, BET, and TGA were used to characterize the produced material‘s structural and optical properties. The presence of a single phase spinel structure with a distinctive plane (311) was verified by the XRD peak of 2 at 36.9° for Co3O4‐Bi2O3. The SEM pictures revealed clustered consolidated spheres, suggesting particle homogeneity and high interconnectedness. The HR‐TEM and SAED pictures revealed an average crystallite size of 28 nm for the Co3O4‐Bi2O3 heterojunction. The UV‐DRS spectral data demonstrated a 2.1 eV reduction in band gap energy for Co3O4‐Bi2O3 (whereas Co3O4 is 2.4 eV and Bi2O3 is 2.7 eV). Under solar light irradiation, pristine Co3O4, Bi2O3, and Co3O4‐Bi2O3 composites were investigated for photocatalytic degradation of Methylene Blue (MB) and Malachite green (MG) dyes. By adjusting factors such as pH, starting dye concentration, catalyst dosage, and agitation duration, the optimal efficiency was determined. The acquired results showed Co3O4‐Bi2O3 ′s superior activity over both precursors. The composite obtained maximal degradation of 98 % (at pH=11) and 97 % (at pH=9) for MB and MG, respectively. The enhanced photo degradation activity of Co3O4‐Bi2O3 can be due to larger visible light absorption, increased surface area, and decreased h+/e− recombination. The reactive species trapping study was performed to determine the importance of superoxide and hydroxyl radicals during photo degradation. Dye degradation was governed by a pseudo‐first‐order kinetic model. The reusability and stability of Co3O4‐Bi2O3 were confirmed by utilizing the same material for five consecutive runs with both MB and MG dyes. Mass spectra analysis provided insights into the successful degradation of dyes, elucidating intermediate products. The synthesized Co3O4‐Bi2O3 nanocomposite offers unrivalled advantages in terms of structural and optical properties, superior photocatalytic activity, and remarkable stability, making it a promising candidate for efficient dye degradation applications without the formation of toxic by‐products.

Construction of High-Activity Nano-NiTiO3/g-C3N4 Composite Catalysts for Enhanced Photodegradation Activities under Visible Light

Nickel titanate (NiTiO3) semiconductors and graphitic carbon nitride (g-C3N4) have attracted great attention as photocatalysts in the degradation of environmental pollutants because of their visible-light-driven activity. But the utilizations of both semiconductors are limited by their low specific surface area. In this study, a nano-NiTiO3/g-C3N4 photocatalyst was successfully synthesized by optimizing the preparation method of photocatalyst precursors. Compared with the bulk g-C3N4 and bulk NiTiO3/g-C3N4 composite photocatalysts, the nano-NiTiO3/g-C3N4 composite catalyst displayed a larger specific surface area, a more abundant pore size structure, and superior carrier separation capabilities. According to the pseudo-first-order, the degradation rate of MB was more than 2.5–19.7 times higher than that of previous studies. The superoxide radicals (·O2−) and holes (h+) played significant roles in the photocatalytic reaction of MB. This study provides a new idea for the synthesis of photocatalysts and the improvement in photocatalytic performance.

Rational design of full-spectrum visible-light-responsive bimetallic sulfide Bi2S3/CoS2 composites for high-efficiency photocatalytic degradation of naproxen and bacterial inactivation

Photocatalytic water decontamination has emerged as a highly promising technology for efficient and rapid water treatment, harnessing sustainable solar energy as its driving force. In this study, we prepared visible-light active Bi2S3/CoS2 composites for the degradation of naproxen (NPX) and the inactivation of Escherichia coli (E. coli). The homogeneous dispersion of CoS2 was stably integrated with Bi2S3, resulting in a significant enhancement of the specific surface area, efficient utilization of visible light, and effective separation of photogenerated charge carriers. Consequently, this synergistic photocatalytic system greatly facilitated the successful degradation of NPX and the inactivation of E. coli under visible-light irradiation. Compared to the pure Bi2S3 and CoS2 catalysts, the Bi2S3/CoS2 (1:2) composites displayed significantly enhanced photodegradation activity, achieving 96.46% (k = 0.2847 min−1) degradation of NPX within 90 min and maintaining good recyclability with no significant decline after six successive cycles. Additionally, the photocatalytic inactivation of E. coli results indicated that Bi2S3/CoS2 composites exhibited excellent performance, leading to the inactivation of 7 log10 cfu mL−1 of bacterial cells after 150 min of visible-light exposure. Scanning Electron Microscopy (SEM) and K+ ions leakage tests demonstrated that the destruction of the E. coli cell membrane structure resulted in cell death. The outcomes of this work suggest that Bi2S3/CoS2 composites hold significant potential for treating water contaminated with antibiotic and microbial pollutants.

Decorated ZnO nanorods with Bi2S3 nanosheets for enhanced photocatalytic removal of antibiotics and analgesics: Degradation mechanism and pathway

Novel nanorods (NRs) of Bi2S3-ZnO (BZ) heterojunction have been prepared using a microwave-assisted hydrothermal approach. The photocatalytic behavior of BZ heterojunction NRs has been investigated under simulated solar irradiation against the mineralization of meloxicam (MX) analgesics, sulfamethoxazole (SMX), trimethoprim (TMP) antibiotics, as well as crystal violet (CV) and malachite green (MG) dyes. XRD, FTIR, SEM, EDX, TEM, UV–Vis, BET, Zeta potential, and Pl techniques are used to characterize the prepared samples. The TEM results showed that the ZnO NRs are wrapped with Bi2S3 NSHs. For SMX and MX, the degradation rate of BZPCis 2.46 and 1.6 fold greater than that for pristine ZnO NRs, respectively. Furthermore, the BZ NRs heterojunction demonstrated 100% degradation efficiency for SMX, SM, TMP, and CV after 120 min, and after 60 min for MG. The enhanced photodegradation activity of BZ NRs photocatalyst (PC) is assigned to its high absorption ability for visible light, increased surface area, adsorption capability, as well as inhibition of the hole-electron recombination process according to the PL study. Furthermore, the quenching experiment exposed that hydroxyl radicals (·OH) exhibit a significant role in the photodegradation process.Moreover, after 5 cycles, the photocatalytic degradation efficiency of the BZ PC remained constant, confirming its high stability and reusability. The special charge transfer pathway over the BZ PC has been investigated, which will assistin the design of systems with superior photocatalytic properties. The degraded productsand pathwaysis also proposed.Conclusively, BZis considered stable, efficient, and non-selective PC for green solar-driven photocatalytic degradation.

Construction of 3D flower-like Bi5O7I/Bi/Bi2WO6 heterostructure decorated NiFe2O4 nanoparticles for photocatalytic destruction of Levofloxacin in aqueous solution: Synergistic effect between S-scheme and SPR action

Promoting the separation activity of photo-induced carriers via the design of heterostructure photocatalysts remains a vital challenge. In the present study, multistep strategies were developed to construct the Bi5O7I/Bi/Bi2WO6/NiFe2O4 heterojunction by in situ growth of Bi/Bi2WO6 and NiFe2O4 species on the surface of Bi5O7I microspheres, forming a 3D flower-like structure as verified by characterization technologies. The developed heterojunction reflected superior photodegradation activity (97.5% in 90 min) toward levofloxacin (LEV) under visible light irradiation. The enhanced photodegradation activity of the Bi5O7I/Bi/Bi2WO6/NiFe2O4 nanocomposite could be attributed to the synergistic outcomes of the S-scheme mechanism and the plasmonic action of Bi metal in one system. Furthermore, the Bi metal can directly harvest the simulated sunlight under the surface plasmon resonance (SPR) action, which contributes to generating a large number of electron-hole pairs. Some influencing factors like pH, LEV concentration, and catalyst loading were also discussed. The photocatalytic degradation pathways of LEV were investigated depending on the detected intermediate products. The radical experiment and ESR results stated that the major contribution of •OH, •O2−, and h+ radicals in LEV destruction. The recyclability experiments indicated the excellent stability and facile reusability of the magnetic Bi5O7I/Bi/Bi2WO6/NiFe2O4 composite. Finally, the photocatalytic mechanism for LEV destruction was clarified in terms of trapping experiments and band-gap discussions. This work introduces a clear technology to fabricate a quaternary S-scheme heterojunction boosted by the plasmonic effect of Bi metal to accelerate the charge separation ability and create a powerful redox potential to achieve a desirable LEV treatment process.

Facile synthesis of N-doped biphasic TiO2 nanoparticles with enhanced visible light-driven photocatalytic performance

Undoped and N-doped TiO2 anatase/brookite mixed-phase nanoparticles were synthesized via a facile sol-gel method using urea as a nitrogen source. Surprisingly, nitrogen played a dual role in doping and controlling the anatase and brookite phases in the nanoparticles. The as-synthesized photocatalysts were characterized by powder X-ray diffraction (PXRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis and UV–vis diffuse reflectance spectroscopy (DRS). PXRD results revealed that TiO2 nanoparticles consisted of a mixture of anatase and brookite crystalline phases where the anatase phase increased with increasing urea concentration (1–60 wt. %), and the pure anatase phase was found at a urea concentration of ≥15 wt. %. N-doped anatase/brookite mixed-phase (brookite ̴ 20 wt. %) nanoparticles exhibited superior photocatalytic activity over others in degrading rhodamine-B (RhB) under simulated visible light irradiation, and its photocatalytic performance was comparable to that of Degussa P25. The enhanced photodegradation activity was credited to biphasic composition, narrower bandgap energy, and stronger light absorption in the visible region.

Construction of a Direct Z-Type Heterojunction Relying on Mos2 Electronic Transfer Platform Towards Enhanced Photodegradation Activity of Tetracycline

Construction of a Direct Z-Type Heterojunction Relying on Mos2 Electronic Transfer Platform Towards Enhanced Photodegradation Activity of Tetracycline

Sb2X3 (X = S, Se) nanowires/graphene aerogel monoliths for effective photodegradation of dye/drug under visible light irradiation

The visible-light-responsive photocatalysts with high efficiency have been attracting tremendous focus in environmental remediation. Herein, three-dimensional (3D) Sb2X3 (X = S, Se) nanowires/graphene aerogel (Sb2X3/GA) monoliths were prepared by a facile hydrothermal route. The as-prepared Sb2X3/GA monoliths show the shape of a cylinder with a hierarchical porous structure. FESEM and porosimetry analyses revealed that the monoliths have high porosity, large total pore area as well as large pore volume. Sb2X3/GA demonstrated excellent photodegradation performance for the representative anionic/cationic dyes (methyl orange, rhodamine B, and crystal violet) and antibiotic drug (tetracycline hydrochloride) under 120 min of visible light irradiation. The degradation efficiencies of Sb2X3/GA were found to be 92.6–99.8% for the above-mentioned dye/drug, which were much larger than that of the pristine Sb2X3 nanowires. The enhanced photodegradation activity could be ascribed to the synergistic effect between the Sb2X3 nanowires and graphene aerogel, which was confirmed by the results of the photoluminescence and electrochemical impedance spectra. These findings provide an innovative strategy for designing 3D visible-light-responsive photocatalysts for water purification.

Facile assembly and enhanced visible-light-driven photocatalytic activity of S-scheme BiOBr/g-C3N4 heterojunction for degrading xanthate in wastewater

The S-scheme BiOBr/g-C3N4 heterostructure composites with varying mass ratios were synthesized via a simple hydrothermal route. Compared to bare BiOBr and g-C3N4, the BiOBr/g-C3N4-10% photocatalyst performed the significantly enhanced photodegradation activity for ethyl xanthate in mineral flotation wastewater under visible light and possessed superior reusability as demonstrated by the reuse test. The degradation efficiency of BiOBr/g-C3N4-10% composite towards ethyl xanthate was up to 96.1% in 120 min, and its reaction rate constant was equal to about 6.3 times and 24.6 times that of bare BiOBr and g-C3N4, respectively. The improved visible-light-driven photodegradation activity was mainly attributed to the construction of S-scheme BiOBr/g-C3N4 heterojunction resulting in the effective separation of carriers. The results showed that superoxide radical (•O2–) played a dominant role in the degradation reaction. Furthermore, the carrier transfer mode in the S-scheme heterojunction and possible xanthate degradation mechanism was proposed. This paper provides a new idea for preparing S-scheme heterojunction and the construction of a high-efficiency photocatalytic system.

In-situ fabrication of 3D/1D p-NiO/p-ZrO2 heterojunction composites with enhanced photo-degradation activity towards methyl orange and benzimidazole

In current work, p-p type NiO/ZrO2 composites (NZO-1 and NZO-2) were fabricated with the help of single step co-precipitation route. NiO to ZrO2 ratio was kept 9:1 and 8:2 for NZO-1 and NZO-2, respectively. As prepared composites were characterized by different physiochemical techniques. XRD data confirmed that cubic and monoclinic crystal phases of NiO and ZrO2 were present in both NZO-1 and NZO-2 composites. With the increase in concentration of ZrO2, crystallite size of NiO/ZrO2 was decreased from 16 nm to 14 nm. SEM analysis showed the formation of 3D quasi spherical particles of NiO and 1D nanoneedles of ZrO2. With FT-IR investigations different M − O bonds related to Ni–O and Zr–O were observed in NZO-1 and NZO-2. When used for photocatalytic activities, NZO-2 outperformed as compared to NZO-1 and pure constituents (NiO and ZrO2). In brief, NZO-2, NZO-1, NiO and ZrO2 removed 93, 80, 62 and 45% of Methyl orange (MO) dye in presence of natural sunlight within 120 min. Clearly, NZO-2 hold optimum concentrations of NiO and ZrO2 with a kinetic rate constant value of 0.019 min−1. Scavenging experiments disclosed electrons, superoxide radicals and holes were the main species involved in the photo-removal of MO. For benzimidazole, sufficient photo-degradation activity (57%) was observed in presence of NZO-2. Photo-catalytic investigations suggested that NZO-2 can be used as efficient photocatalyst for the treatment of multiple pollutants from contaminated water.

Engineering of heterojunction TiO2/CaIn2S4@rGO novel nanocomposite for rapid photodegradation of toxic contaminants

The in-situ reduction of GO to rGO and simultaneous deposition of TiO2 and varying concentrations CaIn2S410 % (rGO-C1), 20 % (rGO-C2), and 40 % (rGO-C3) resulted in the formation of robust photocatalysts for the degradation of aqueous (azo and thiazine) dyes methylene blue (MB), congo red (CR) and real wastewater. Batch experiments were performed to analyse the effect of pH, catalyst dose, initial dye concentration and time. Compared to other synthesised composites, rGO-C2 demonstrated enhanced photodegradation activity, with a degradation efficiency of almost 100 % within 25–30 min. A possible mechanism for the photodegradation of dyes was also proposed, and post-degradation products were analysed using the LC–MS technique. The kinetic studies show that the degradation efficiency of rGO-C2 followed pseudo-first-order reaction kinetics (k = 0.027 min−1. The rGO-C2 photocatalysts demonstrated excellent photocatalytic degradation in real textile industry wastewater and landfill leachate wastewater. It displayed excellent recyclability and stability up to the four-cycle.

CdS Coated Mn Doped ZnO Nanospheres as Textile Catalyst: Fabrication, Physicochemical Techniques and Dye Removal Under Natural Light

ZnO as a promising photocatalyst has gained much attention for the removal of organic pollutants from water. However, the main drawbacks of the relatively low photocatalytic activity and high recombination rate of photo excited electronhole pairs, restrict its potential applications. Promoting the spatial separation of photo excited charge carriers is of paramount signi? cance for photocatalysis, because the dierence in the band positions make the potential gradient at the composite boundary. In this work, our aim is to enhance the photocatalytic efficiency of CdS coated Mn doped ZnO nanospheres under solar light irradiation. Objectives in this work are, to fabricate the CdS coated Mn doped ZnO nanospheres by a simple ethanolic dispersion method, and its applied for testing the photocatalytic activity of methylene blue (MB) dye. The fabricated binary composites were analyzed with different physicochemical techniques like PXRD, SEM with EDX, UV-DRS, PL and TEM. The photocatalytic degradation results have revealed that, the CdS coated Mn doped ZnO nanospheres exhibits admirable activity toward the photocatalytic degradation of the MB. The remarkably enhanced photocatalytic activity of CdS coated Mn doped ZnO nanospheres can be interpreted in terms of lots of active sites, which efficiently separate the photo generated electron and holes. A plausible mechanism is also elucidated via active species trapping experiments with various scavengers, which indicating that the photo generated O2 -and. OH radicals play a crucial role in photo degradation reactions under visible light irradiation. This work suggests that, the rational design and construction of heterostructures is powerful for developing highly efficient, and reusable visible-light photocatalysts for environmental purification and energy conversion. The enhanced photo degradation activity indicates the potential of the nanocomposite for the treatment of organic pollutants from the textile wastewater.

CdS Coated Mn Doped ZnO Nanospheres as Textile Catalyst: Fabrication, Physicochemical Techniques and Dye Removal Under Natural Light

ZnO as a promising photocatalyst has gained much attention for the removal of organic pollutants from water. However, the main drawbacks of the relatively low photocatalytic activity and high recombination rate of photo excited electronhole pairs, restrict its potential applications. Promoting the spatial separation of photo excited charge carriers is of paramount signi? cance for photocatalysis, because the dierence in the band positions make the potential gradient at the composite boundary. In this work, our aim is to enhance the photocatalytic efficiency of CdS coated Mn doped ZnO nanospheres under solar light irradiation. Objectives in this work are, to fabricate the CdS coated Mn doped ZnO nanospheres by a simple ethanolic dispersion method, and its applied for testing the photocatalytic activity of methylene blue (MB) dye. The fabricated binary composites were analyzed with different physicochemical techniques like PXRD, SEM with EDX, UV-DRS, PL and TEM. The photocatalytic degradation results have revealed that, the CdS coated Mn doped ZnO nanospheres exhibits admirable activity toward the photocatalytic degradation of the MB. The remarkably enhanced photocatalytic activity of CdS coated Mn doped ZnO nanospheres can be interpreted in terms of lots of active sites, which efficiently separate the photo generated electron and holes. A plausible mechanism is also elucidated via active species trapping experiments with various scavengers, which indicating that the photo generated O2 -and. OH radicals play a crucial role in photo degradation reactions under visible light irradiation. This work suggests that, the rational design and construction of heterostructures is powerful for developing highly efficient, and reusable visible-light photocatalysts for environmental purification and energy conversion. The enhanced photo degradation activity indicates the potential of the nanocomposite for the treatment of organic pollutants from the textile wastewater.

Interfacial coupling effects in α-Fe2O3/g-C3N4 composite magnetically separable heterojunction with upgraded Z-scheme photocatalytic performance of mixed organic pollutant degradation

Photocatalysis has fascinated wide consideration due to its promising advantage in wastewater treatment. And the metal-oxides and g-C3N4 that possess Z-scheme heterojunctions have become the energetic photocatalysts (PCs) in degrading the organic impurities. In this work, a novel magnetic separable g-C3N4/α-Fe2O3 (GFE) nanocomposites (NCs) were fabricated by a facile hydrothermal strategy. Structural, morphological, optical, surface area and magnetic belongings of GFE composites were effectively explored using XRD, FT-IR, XPS, FESEM, HRTEM with EDX mapping, BET, UV-DRS and PL spectra. The (g-C3N4/20 wt % α-Fe2O3) GFE2 composite PCs were verified robust with significantly upgraded the photocatalytic efficiency for (anionic) RhB (97.2%) and (cationic) MB (90.6%) mixed aqueous organic pollutants degradation in 150 min under visible-light exposure, which was favourably higher than to GCN (65.2%) and α-Fe2O3 (16.6%) PCs. Moreover, the as-obtained GFE composite PCs also exposed great stability after five successive recyclabilities. The enhanced photo-degradation activity was largely ascribed to the extended visible-light fascination ability, high surface area, augmented active sites and strong redox ability relatively. Also, the energetic formation of α-Fe2O3 coupled g-C3N4 heterojunction that skilled the probable recombination rate and beneficial for the separation of photo-excited electron and hole (e−/h+) pairs based on active “Z-scheme” mechanism was liable for eliminating organic mixed pollutants.

Enhancement Photocatalytic Activity of Mn Doped Cds/Zno Nanocomposites for the Degradation of Methylene Blue Under Solar Light Irradiation

Abstract In this study, Mn doped CdS/ZnO nanocomposites synthesized by co-precipitation method and its photocatalytic activity was tested using methylene blue under solar light irradiation. The prepared hybrid nanocomposites are characterized by using different physicochemical techniques including XRD, FESEM, EDX, TEM, UV-vis DRS and PL analysis. From the XRD analysis, Mn doped ZnO/CdS nanocomposite diffraction peaks only reflect the binary crystalline structures of ZnO and CdS. However, there is no characteristic peak of Mn is found that may be because of low content of Mn doped on ZnO/CdS. But Mn (2.9 wt%) was detected in the Mn doped ZnO/CdS nanocomposite, which was measured by EDX analysis. The FESEM and TEM results exhibit the surface particle of Mn doped ZnO/CdS nanocomposite which have spherical nature and confirmed the formation of Mn doped ZnO/CdS nanocomposites. The photocatalytic degradation results have revealed that the Mn doped CdS/ZnO nanocomposites exhibit admirable activity toward the photocatalytic degradation of the MB. The reason for excellent photocatalytic activity of Mn doped CdS/ZnO nanocomposites indicates the absorbance band shifted to red region and reduction of recombination of photogenerated electron-hole, which is in good agreement with UV-visible DRS analysis and PL study results. The fitted kinetic plots showed a pseudo-first-order reaction model and the appropriate rate constants were found to be 0.0068 min−1, 0.00846 min−1, and 0.0188 min−1, for ZnO, 25 % CdS/ZnO, and 0.8 mol% Mn doped CdS/ZnO nanocomposites, respectively. The maximum photocatalytic activity was achieved by 0.8 mol% Mn doped CdS/ZnO nanocomposites with a 95% degradation efficiency of MB. Hydroxyl and superoxide radicals, having a vital role in the degradation of MB, confirmed scavenging experiments. In addition, the recycling tests displays that the Mn doped CdS/ZnO nanocomposites have shown good stability and long durability. The enhanced photodegradation activity of Mn doped CdS/ZnO nanocomposites indicates the potential of the nanocomposite for the treatment of organic pollutants from the textile wastewater.

Porous and Few-Layer Carbon Nitride Nanosheets via Surface Steam Etching for Enhanced Photodegradation Activity

Porous and Few-Layer Carbon Nitride Nanosheets via Surface Steam Etching for Enhanced Photodegradation Activity

Novel Bi4O5Br2/MnxZn1-xFe2O4 magnetic composite with an enhanced photodegradation activity and excellent recyclability

Bi4O5Br2/MnxZn1-xFe2O4 nanocomposites with impressive photocatalytic and recyclability properties were synthesised using a microemulsion method. In addition to the photocatalytic effect, the crystal structure and morphology, photoelectrochemical characteristics, magnetic effect and photocatalytic mechanism of Bi4O5Br2/MnxZn1-xFe2O4 were also investigated. As the best sample, the removal rate of the Bi4O5Br2/MnxZn1-xFe2O4 photocatalyst with 7.5 wt% MnxZn1-xFe2O4 to rhodamine B (RhB) reached up to 99.4% within 60 min. The enhanced photocatalyst activity was mainly attributed to the type-II heterojunction formed between Bi4O5Br2 and MnxZn1-xFe2O4, which not only optimised the energy band structure, but also led to the building of an interior electromagnetic field within the Bi4O5Br2/MnxZn1-xFe2O4 heterojunction. Meanwhile, the constantly producing and migrating h+ and ·O2− were the main active components. In particular, the results of the saturation magnetization tests and magnetic recovery experiments revealed that the magnetic composite photocatalyst can be recovered effectively. The results of the removal rate of RhB remaining at 85.2% after five uses reflected the advantages of the stability of the Bi4O5Br2/MnxZn1-xFe2O4 photocatalyst. In brief, this paper presented an original idea to develop a novel composite magnetic photocatalyst and research the enhancement mechanism of photocatalysis.

Mechanism Insight into an Unprecedented Dual Series‐Parallel Photocharge Separation in Quaternary Cu2O Facet Junctions

AbstractUncovering the contribution of anisotropic crystal facets in single‐crystalline photocatalysts is still a challenge in fundamental study. Here, the mechanism underlying facet junction‐dependent photocharge separation in polyhedral Cu2O is demonstrated, which is beneficial for understanding why 50‐faceted Cu2O exhibiting quaternary {100}/{110}/{111}/{522} facet junction possesses an enhanced photodegradation activity toward tetracycline than that of the 26‐faceted Cu2O exhibiting ternary {100}/{110}/{111} and 18‐faceted Cu2O exhibiting binary {100}/{110} facet junction. Density functional theory (DFT) calculations and selective photodeposition results confirm that hierarchical facet junctions are formed in a 50‐faceted Cu2O, which could be regarded as one parallel connection between binary {110}/{111} and ternary {110}/{522}/{100} series facet junction for conduction band minimum, and another parallel connection between binary {100}/{522} and ternary {111}/{110}/{522} series facet junction for valence band maximum, leading to an unprecedented dual series‐parallel transfer pathway for more efficiently improved photocharge separation. Hopefully, this study would be a beneficial guideline for scientific researchers currently concentrating on the facet junction engineering of polyhedral photocatalysts.