Degradation Of Organic Dye Pollutants Research Articles

Photocatalytic performance of (Zn,Me)–SnO2 nanoparticles (Me= Nb5+ or W6+) under UV light for efficiently degradation of organic dye pollutants

In this study (Zn,Nb)-doped SnO2 and (Zn,W)-doped SnO2 were synthetized using chemical route by calcination at 600 °C/2 h and milling at 500 rpm/1 h to verify its behavior as a photocatalyst. The powders showed high surface area: 57.1 m2/g for (Zn,Nb)-doped SnO2 and 74.3 m2/g for (Zn,W)-doped SnO2, both showed 10–25 nm of average diameter and rutile crystalline phase after morphological and structural characterizations. UV–vis spectroscopy indicated a band gap of 3.53 eV for (Zn,Nb)–SnO2 and 3.35 for (Zn,W)–SnO2. The photocatalytic activity was verified through the decomposition of Rodhamine B (RhB) aqueous solution under ultraviolet light radiation of 9W. After 120 min the efficiency of (Zn,Nb)–SnO2 was 68.5 % and for (Zn,W)–SnO2 was 71.1 %. Using a UV-lamp of 11W the efficiency in photodiscoloration of RhB aqueous solution increased to 83.2 % with (Zn,W)-doped SnO2 powder in a shorter irradiation time (90 min), indicating its potential use as nanostructured photocatalyst ceramic powder.

Constructed of Cd-based organic framework heterostructure material for solar-powered organic dye purification

A novel water-stable Cd-based organic framework material (Cd-MOF) has been synthesized based on the 4,4′-([2,2′-bipyridine]-6,6′-diylbis(oxy))phthalic acid (H4L) ligand and Cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) with a solvothermal method. We also prove that the rational design and preparation of Cd-MOF\\Ag heterojunctions by depositing Ag nanoparticles on the surface of Cd-MOF is an effective photocatalyst for the degradation of organic dyes in water. The photodegradation rates of RhB and MO were significantly improved under simulated sunlight conditions (AM1.5G), which reaching 0.68 and 1.549 min−1 g−1, respectively. The prominent performance is attributed to the efficient separation of photo-generated electrons and holes caused by the composite heterojunction of Cd-MOF/Ag. The surface plasmonic resonance (SPR) effect of Ag nanoparticles and the Schottky junction between Ag and Cd-MOF play crucial role in the photocatalytic degradation process. This work provides a new strategy for preparing photocatalysts and promoting the development of the degradation of organic dye pollutants in effluent with MOF-based material as photocatalysts.

S-Schematic CuWO4/ZnO nanocomposite boosted photocatalytic degradation of organic dye pollutants

S-schematic CuWO4/ZnO nanocomposite photocatalyst was synthesized by an impregnation method. Synthesized CuWO4 and ZnO nanoparticles, and CuWO4/ZnO nanocomposites were thoroughly characterized. X-ray diffraction (XRD) analysis of the CuWO4/ZnO nanocomposite confirmed the respective triclinic and hexagonal wurtzite structures of CuWO4 and ZnO crystals. Raman and Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS) revealed bond formations in CuWO4 and ZnO, and confirmed the synthesis of the CuWO4/ZnO nanocomposite. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed CuWO4 nanoparticles adhered to ZnO aggregates. Energy dispersive X-ray spectrometry (EDS) confirmed the distribution of CuWO4 on the ZnO aggregates. UV–Vis diffuse reflectance spectroscopy (DRS) showed optical bandgap energies of 2.36 eV for CuWO4 and 3.18 eV for ZnO nanoparticles. The photocatalytic performance of the CuWO4/ZnO nanocomposite was investigated through the degradation of the cationic dyes methylene blue (MB) and Rhodamine B (RhB) and the anionic dye methyl orange (MO). A 5.0%CuWO4/ZnO nanocomposite degraded 100% of MB within 120 min, 91.02% of RhB within 300 min, and 89.13% of MO within 300 min. The pseudo-first order kinetic rate constant fit well for the degradation of all the dyes on the CuWO4/ZnO nanocomposite. The CuWO4/ZnO nanocomposite could better degrade the cationic dyes than the anionic dye in an aqueous solution. The hole (h+), the hydroxyl radical (•OH), and the superoxide ion (•O2−) were the active species responsible for degrading MB, RhB and MO dyes. The proposed CuWO4/ZnO nanocomposite could be applied for environment friendly wastewater treatment.

Synthesis of highly efficient ternary phase graphene/Bi/SnO2 photocatalyst for degradation of organic dye pollutants

In this work, graphene nanosheets (GNs) are prepared from graphite rods obtained from waste dry-cell batteries using the electrochemical exfoliation (ECE) method. Then GNs used as a matrix to modify tin oxide (SnO2) and Bismuth (Bi) nanoparticles to prepare a binary phase SnO2@G and ternary-phase Bi@SnO2@G nanocomposite materials by wet-chemical method and used as a photocatalysts for degradation of organic dye pollutants. XRD diffraction pattern clearly confirmed the presence of tetragonal crystal system of SnO2 which was maintaining its structure in SnO2@G and G/Bi/SnO2. The stretching and bending vibrations of the functional groups were analyzed using FTIR analysis. FESEM images demonstrated the surface morphology and the texture of the as synthesized sample. Raman Spectroscopic investigation was carried out to confirm the in-plane blending of SnO2 and graphene inside the composite matrix. The as-prepared ternary-phase Bi@SnO2@G-based photocatalyst showed high degradation efficiency of 99.6% and 94.5% for direct blue (DB) and methyl blue (MB) dyes, respectively, under visible light irradiation by (i) minimizing the hole and electron recombination, (ii) providing a high surface area, and (iii) reducing the band gap energy. This study provides an effective, low-cost, and smart approach for producing GNs on a wide scale from battery waste along with nanohybrid composites with high photocatalytic efficiency.

Photocatalytic Degradation of Organic Dye Pollutants Using ZnO Nanoparticles Synthesized from Plumeria alba L. Leaf Extract

Photocatalytic Degradation of Organic Dye Pollutants Using ZnO Nanoparticles Synthesized from Plumeria alba L. Leaf Extract

Bismuth-doped lanthanum ferrite perovskites: A promising approach for enhancing photo-Fenton degradation of organic dye pollutants

Fabrication of efficient perovskite photo-Fenton catalytic systems is recognized as an effective strategy for clean water production. However, modifying perovskite catalysts effectively remains a formidable challenge. In this study, we prepared Bi-doped LaFeO3 photo-Fenton catalysts using a facile microwave-assisted method. Various characterization techniques confirmed the successful formation of these Bi-doped LaFeO3 perovskite materials. The photo-Fenton activity of the Bi-doped LaFeO3 perovskite materials with varying Bi content was assessed by monitoring the degradation of methylene blue (MB) dye solution. Remarkably, the optimized Bi-doped LaFeO3 (referred to as LBFO3) catalyst achieved approximately 93.64% degradation of MB within 100 min of visible light exposure, demonstrating exceptional efficacy in treating wastewater containing organic dye pollutants. The enhanced photocatalytic activity of the LBFO3 perovskite materials arises from the incorporation of Bi, leading to an expanded optical absorption range, increased specific surface area, and enhanced separation and migration of photo-generated carriers. Importantly, the LBFO3 photo-Fenton system exhibited remarkable stability during four successive cycling treatments, indicating promising practical applications. Additionally, quenching experiments were conducted to elucidate electron transfer in the LBFO3 catalyst related to the photo-Fenton degradation mechanism of MB. This study might pave the way toward designing novel perovskite based photo-Fenton systems for highly efficient degradation of waterborne contaminants.

Zircon-Type CaCrO4 Chromite Nanoparticles: Synthesis, Characterization, and Photocatalytic Application for Sunlight-Induced Degradation of Rhodamine B.

The degradation of organic dye pollutants is a critical environmental issue that has garnered significant attention in recent years. To address this problem, we investigated the potential of CaCrO4 chromite (CCO) as a photocatalyst for the degradation of cationic and anionic dye solutions under sunlight irradiation. CaCrO4 was synthesized via a sol-gel auto-combustion route and sintered at 900 °C. The Rietveld refined XRD profile confirmed the zircon-type structure of CaCrO4 crystallized in the tetragonal unit cell with I41/amd space group symmetry. The surface morphology of the sample was investigated by field emission scanning electron microscopy (FESEM), which revealed the polyhedral texture of the grains. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) studies were carried out to analyze the elemental composition and chemical states of the ions present in the compound. Fourier transform infrared (FT-IR) spectroscopy analysis revealed the vibrational modes corresponding to the tetrahedral and dodecahedral metal oxide bonds. The optical band gap was approximated to be in the range of 1.928 eV by using the Tauc relation. The CaCrO4 catalyst with different contents (5, 20, 35, and 50 mg) was investigated for its photocatalytic performance for the degradation of RhB dye solution under sunlight irradiation using a UV-Vis spectrometer over the experimental wavelength range of 450-600 nm. The degradation efficacy increased from 70.630 to 93.550% for 5-35 mg and then decreased to 68.720% for 50 mg in 140 min under visible light illumination. The comparative study demonstrates that a higher degradation rate was achieved for cationic than anionic dyes in the order RhB > MB > MO. The highest deterioration (93.80%) was achieved for the RhB dye in 140 min. Equilibrium and kinetic studies showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of 21.125 mg/g was observed for the catalyst concentration of 35 mg. From the cyclic test, it has been observed that the synthesized photocatalyst is structurally and morphologically stable and reusable. The radical trapping experiment demonstrated that superoxide and hydroxyl radicals were the primary species engaged in the photodegradation process. A possible mechanism for the degradation of RhB has been proposed. Hence, we conclude that CaCrO4 can be used as an efficient photocatalyst for the remediation of organic dye pollutants from the environment.

Superior photocatalytic performance of ancillary-oxidant-free novel starch supported nano MFe2O4 (M = Zn, Ni, and Fe) ferrites for degradation of organic dye pollutants

This work presents the effectual degradation of MB and MO dyes in an aqueous solution under UV light irradiation on nano ZnFe2O4, NiFe2O4, and Fe3O4 without using any supplementary oxidants has been reported. Nano ZnFe2O4, NiFe2O4, and Fe3O4 are successfully prepared via a co-precipitation technique utilizing biodegradable starch as a surfactant. XRD patterns reveal a pure spinel phase for all the samples. FTIR spectra confirm the successful embedding of the starch surfactant. SEM micrographs exhibit tiny spherical particles of size 5–8 and 4–6 nm for ZnFe2O4 and NiFe2O4 but spherical particles of 8–10 nm and flake-like particles of ∼14 nm thick for Fe3O4. N2 sorption studies show type-IV isotherms typical of mesoporous structures. The direct bandgap of these ferrite nanoparticles is 2.03–2.15 eV, related to the metal D-d onsite transfers, which are permitted by spin but prohibited by parity. MB decolorization of 99% is achieved in less than 2 h for all the samples; in contrast, MO decolorization takes relatively longer irradiation. The decolorization kinetics suggests that the pseudo-second-order model is more appropriate to explain the decolorization process of MB and MO by the catalysts. The order of photocatalytic activity evaluated from rate constant (k1) per SSA values is Fe3O4 < ZnFe2O4 < NiFe2O4 for both MB and MO decolorization. NiFe2O4 photocatalyst shows the best effect on the decolorization of both dyes due to its low bandgap and high surface area. All the ferrite catalysts demonstrate high stability with no substantial deterioration of photocatalytic activity even after three cycles. The results of this study endorse that the nano ferrites prepared in this work are potential candidates for the photocatalytic degradation of aqueous solutions of MB and MO.

Cs2SnI6 perovskites nanostructures as excellent photocatalytic degradation of organic dye pollutants in water under visible light: Synthesis and characterization

Pollution of surface waters containing chemical dye combinations and/or biological materials can have adverse effects on human health and other organisms, even in small quantities. The photocatalytic oxidation procedure has been widely regarded as a commercially viable method of removing environmental pollutants. In recent research, Caesium-hexaiodostannate nanostructures (Cs2SnI6) were prepared through a co-precipitation approach and their photocatalytic performance was analyzed. A number of surfactants were examined for their influence on the structure, purity, and morphology of the sample. It was found in the SEM data that the presence of surfactants has a negative impact on the morphology, which may be due to the inability to remove surfactants by calcination at high temperatures. Photocatalytic activity of Cs2SnI6 catalysts was demonstrated over a variety of organic dyes, including methylene blue (MB), rhodamine b (RhB), methyl orange (MO), and methyl violet (MV). Upon exposure to visible light for 180 min, 5 ppm methylene blue showed the greatest degradation (84.0%). Cs2SnI6 nanostructures are being applied for the first time in photocatalytic applications. Due to their wide bandgap (1.7 eV) in the visible region, they may be a suitable candidate for water purification. Moreover, the results indicated that the efficiency of photocatalysis was affected by various parameters, including pH, dye concentration, dye types, catalyst dosages, and surfactants. In the recyclability test, Cs2SnI6 nanostructures were found to be stable, and the removal efficiency was reduced by 6.9% after the fifth run.

Interfacial self-assembled dual-functional nanocomposite films for SERS monitoring of visible-light photocatalytic degradation of organic dye pollutants

Photocatalytic degradation by visible-light responsive photocatalysts is an efficient strategy to treat organic dye pollutants and monitoring of the photocatalytic reaction mechanisms and kinetics is important to the design of high-performance photocatalysts. Herein, a dual-functional graphitic carbon nitride/gold nanoparticles (g-C3N4/AuNPs) nanocomposite film is introduced to monitor the photocatalytic reactions by surface-enhanced Raman scattering (SERS) while degrading organic dyes photocatalytically. The nanocomposite film fabricated by two-step interfacial self-assembly consists of orderly arranged g-C3N4 film anchored on a closely packed AuNPs monolayer film. The nanoplatform has excellent SERS characteristics such as a rhodamine 6G (R6G) detection limit of 8.8 × 10−10 M, and good SERS detection uniformity with a relative standard deviation (RSD) of 9.62%, which is crucial to quantitative determination and accurate monitoring of the photocatalytic reactions. The nanoplatform is employed in visible-light photocatalytic degradation of organic dyes including R6G, methylene blue, acid orange II, and acid orange 74. The reactions follow the pseudo-first-order kinetics as revealed by SERS and the photocatalytic degradation mechanism is postulated to be the promoted charge separation. The results reveal a high-performance dual-functional nanoplatform suitable for visible-light photocatalytic degradation of organic dye pollutants and SERS monitoring of the reactions.

Green Synthesis and Characterizations of Cobalt Oxide Nanoparticles and Their Coherent Photocatalytic and Antibacterial Investigations

Water pollution is a serious concern for developing and undeveloped countries. Photocatalytic degradation of organic pollutants is an effective degradation method to restrain the green ecosystem. This research article presents a green, low-cost, and benevolent eco-friendly biosynthesis of cobalt oxide (Co3O4) nanoparticles using Curcuma longa plant extract. The UV and visible region absorbance of Co3O4 nanoparticles estimated the Co2+ and Co3+ transitions on the lattice oxygen, and their bandgap of 2.2 eV was confirmed from the UV-DRS spectroscopy. The cubic structure and spherical shape of Co3O4 nanoparticles were estimated by using XRD and TEM characterizations. Plant molecules aggregation and their agglomerations on the nanoparticles were established from FTIR and EDX spectroscopy. Multiple cobalt valences on the oxygen surfaces and their reaction, bonding, and binding energies were analyzed from XPS measurements. The biogenic Co3O4 nanoparticles were executed against gram-positive (Staphylococcus aureus—S. aureus) and gram-negative (Escherichia coli—E. coli) bacteria. A gram-positive bacterial strain exhibited great resistivity on Co3O4 nanoparticles. Degradation of organic dye pollutants on the Co3O4 nanoparticles was performed against methylene blue (MB) dye under the conditions of visible light irradiation. Dye degradation efficiency pseudo-first-order kinetics on the pseudo-first-order kinetics denotes the rate of degradation over the MB dye. This research work achieved enhanced degradation potency against toxic organic dye and their radicals are excited from visible light irradiations. Absorption light and charged particle recombinations are reformed and provoked by the plant extract bio-molecules. In this process, there is no inferior yield development, and electrons are robustly stimulated. Furthermore, the biosynthesized Co3O4 nanoparticles determined the potency of bacterial susceptibility and catalytic efficacy over the industrial dye pollutants.

A novel macro-meso-micro intimate heterogeneous structure constructed 3DOM TiO2/rGO/TiN composite for efficiently solar photocatalysis degradation of organic dye pollutants

The new three-dimensionally ordered macroporous titanium dioxide/reduced graphene oxide/titanium nitride (3DOM TiO2/rGO/TiN) ternary nanocomposites are designed based on the pore structure of 3DOM for efficient photocatalytic dye degradation. A series of structural, optical, and photoelectrochemical characterizations demonstrate that the remarkably improved photocatalytic performance is attributed to the combined effects of macro-meso-micro architecture, abundant reactive sites, improved light response range, and efficient photogenerated charges-holes pair separation and transport. By optimizing the loading amounts of rGO and TiN, 3DOM TiO2/10%rGO/5%TiN nanocomposite exhibits the highest photocatalytic degradation activity, which is 7.4 times higher than 3DOM TiO2. Additionally, the 3DOM TiO2/rGO/TiN ternary photocatalyst shows excellent acid-base resistance and reusability. The mechanism by which 3DOM structure, 2D rGO, and TiN synergy enhance the TiO2 photocatalytic performance was fully revealed comprehensively. This work provides an effective strategy for designing TiO2-base macro-meso-micro intimate heterogeneous structure for photocatalysis degradation of dyes.

Perylene nanoparticle-sensitized MoS2: an efficient solar photocatalyst for the degradation of pollutants

Perylene nanoparticle sensitized MoS2 nano photocatalyst has been developed for the degradation of organic dye pollutants.

Photodegradation of methylene blue using CexZryO2 nanocomposites prepared via a non-stoichiometry method

The effective degradation of organic dye pollutants in water is a research hotspot at present.

Efficient and recyclable degradation of organic dye pollutants by CeO2@ZIF-8 nanozyme-based non-photocatalytic system

Advanced oxidation processes-based catalysis system as the most typical pollutant degradation technology always suffer from poor durability and photo-dependent. Inspired by the fact that some nanomaterials exhibit catalytic properties closer to natural enzymes, a high peroxidase-like activity and stability CeO2@ZIF-8 nanozyme was synthesized in this study for non-photodegradation of dyes pollution. Multiple characterization techniques were applied to prove the successful synthesis of the nanozyme. The influence of different parameters on the catalytic degradation of organic dye by nanozyme was investigated. This nanozyme achieved a maximum degradation efficiency of 99.81% for methyl orange and maintained its catalytic performance in repeated experiments. Possible degradation intermediates and pathways for methyl orange were then proposed. In addition, the CeO2@ZIF-8 loaded starch/agarose films were prepared for the portable and recyclable remediation of real dye wastewater, which maintained more than 80% degradation efficiency after 5 successive cycles. These results suggested that nanozyme based non-photocatalytic system is a potential catalyst for dye degradation and it opens a new avenue to develop high-performance and recyclable catalysts for pollutant remediation.

Recyclable Mussel-Inspired Magnetic Nanocellulose@Polydopamine-Ag Nanocatalyst for Efficient Degradation of Refractory Organic Pollutants and Bacterial Disinfection.

Development of a novel strategy to tackle bacterial-contaminated complex industrial wastewaters containing refractory organic pollutants is of great demand. In this study, polydopamine (PDA)-coated magnetic cellulose nanofiber (MCNF)-loaded silver nanoparticle (AgNP) (MCNF/PDA-Ag) nanocomposites were designed and applied for efficient degradation of organic dye pollutants and inactivation of Escherichia coli (E. coli) in wastewater. In the presence of NaBH4, MCNF/PDA-Ag could achieve a high catalytic reduction rate of 6.54 min-1 for the removal of methylene blue. Similarly, it showed good catalytic reduction performance for methyl orange (0.63 min-1) and 4-nitrophenol (2.94 min-1). The MCNF/PDA-Ag nanocomposites can be easily magnetically recycled and reused with negligible loss of catalytic performance. Moreover, this nanocatalyst also exhibited excellent disinfection performance against E. coli, with more than 99% disinfection ratio at very low doses (50 μg/mL). Overall, this work provides new insights into a delicate design of advanced magnetically recyclable silver nanocomposites with ultrahigh catalytic rates and excellent antibacterial properties from sustainable nature biomass.

Construction of a ternary staggered heterojunction of ZnO/g-C3N4/AgCl with reduced charge recombination for enhanced photocatalysis.

In this study, a series of ternary composite photocatalysts ZnO/g-C3N4/AgCl(x) (x is the amount of AgCl added, x=0.05, 0.1, 0.15 g) were synthesized, and various characterization methods were used to analyze the morphology, structural, and photochemical properties of the above samples. The photocatalytic activity of the obtained samples was evaluated by degrading rhodamine B (RhB) and acid orange (AOII) under xenon lamp irradiation. The results show that the degradation rate of ZnO/g-C3N4/AgCl (0.1 g) is 99% within 60 min, which is much higher than the 38% degradation rate of g-C3N4. After five cycles, the degradation efficiency of RhB and AOII by ZnO/g-C3N4/AgCl (0.1 g) were still 85% and 94%, respectively. In addition to colored dyes, the photocatalytic degradation of colorless tetracycline hydrochloride (TCH) compounds was also investigated to understand the effect of photosensitization on the degradation process. Based on the electronic structure analysis of the DFT calculations, a staggered heterojunction structure was found between g-C3N4, ZnO, and AgCl. The enhanced photocatalytic activity of the ternary composite is mainly attributed to the efficient separation of charge carriers through the synergistic removal of photogenerated electrons in g-C3N4 by ZnO and AgCl. Radical trapping experiments confirmed that •O2- and h+ were the main active species in the reaction system. As a visible light-responsive catalyst, ZnO/g-C3N4/AgCl can be effectively applied to the degradation of organic dye pollutants and has broad application prospects.

Mechanistic Insights into Graphene Oxide Driven Photocatalysis as Co-Catalyst and Sole Catalyst in Degradation of Organic Dye Pollutants

Photocatalysis is a promising route to utilize sunlight, which has been potentially used to solve energy as well as environmental problems with an emphasis on fundamental understanding and technological applications in society. Semiconductors are excellent photocatalysts but often show less efficient activities due to the fast recombination of photogenerated charge carriers and very slow kinetics of surface photochemical reactions. However, recent advancements show promising strategies to improve their photocatalytic activities, including surface modifications using suitable co-catalysts and the development of novel efficient photocatalysts. Graphene oxide (GO) is one of such nanomaterials which shows multifarious roles in photocatalysis with a great potential to act as an independent solar-driven sole photocatalyst. In this minireview, the photochemistry of GO has been discussed in view of its multifarious roles/mechanisms in improving the photocatalytic activity of metal oxide semiconductors, plasmonic nanomaterials, and also their nanocomposites. In addition, recent advancements and applications of such GO-based photocatalysts in photocatalytic degradation of organic dye pollutants, including engineering of GO as the sole photocatalyst, have been discussed. Furthermore, the challenges and future prospects for the development of GO-based photocatalysts are discussed.

Magnetic porous carbon composites for rapid and highly efficient degradation of organic pollutants in water

A magnetic porous carbon composite (MPC) was prepared from metal−organic frameworks (MOFs) by the one-step calcination method. The MPC was characterized by SEM, TEM, TG, DTG, Raman and XPS. The adsorption and degradation performance of MPC towards four organic dyes were investigated. The maximum adsorption amount of magenta on MPC was 191.94 mg g -1 at 25 °C. Furthermore, the MPC showed remarkable stability for it can be recycled 5 times through the facile magnetic separation without obvious loss of activity. The degradation efficiency of MPC toward four kinds of organic pollutants was nearly 100% within 36 ​min, which was much higher than that previously reported. • Magnetic Porous Carbon Composites is prepared by one step carbonization with excellent adsorption and catalytic degradation performance. • Maximum adsorption capacity of magenta on MPCs is 191.94 ​mg ​g −1 and nearly 100% degradation efficiency within 36 ​min. • Ultra-fine nanocrystalline Fe 3 O 4 nanoparticles embedded in the octahedral structure, are favor of removal and degradation of organic dye pollutants. • Carbon layer in MPCs is beneficial to avoid secondary pollution in degradation and contribute the stability and recyclability of MPCs. • MPCs possesses potential green and effective application of organic pollutants treatment in complex matrix.

Boosted electron-transfer/separation of SnO2/CdSe/Bi2S3 heterostructure for excellent photocatalytic degradation of organic dye pollutants under visible light

Nowadays, the discharge of hazardous pollutants from industries into drinking water has become a significant issue worldwide. In the present work, SnO2/CdSe/Bi2S3 heterostructure photocatalyst along with pristine SnO2, CdSe, and Bi2S3 was synthesized via a facile hydrothermal route. The fabricated catalysts were characterized by different analytical techniques such as X-ray diffraction (XRD), Atomic force microscopy (AFM), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy, and Electrochemical impedance spectroscopy (EIS) to study the structural, morphological, optical, and electrochemical properties, respectively. The XRD diffractograms confirmed the formation of nanocomposite having SnO2 (Tetragonal), CdSe (Cubic), and Bi2S3 (Orthorhombic) phases. The photocatalytic experiment results showed that the nanocomposite catalyst exhibited excellent photodegradation than individual catalysts. The nanocomposite catalyst degraded methylene blue (MB) dye entirely after 60 min in visible light illumination, considerably higher as compared to pristine SnO2 (53.8%), CdSe (78.5%), and Bi2S3 (86.3%). The nanocomposite catalyst also has the potential to degrade various pollutants such as rhodamine B (RhB), methyl orange (MO), safranin-O (SO), and methyl red (MR) dyes with efficiency 99.8, 91.7, 75.0, and 98.5 %, respectively, with superior reusability up to 5th cycles against MB dye. The narrow optical energy bandgap in the visible region (UV results), the more significant flow of charge carrier at the catalyst's surface (EIS results), and higher electron-transfer/separation achieved by the heterostructure formation responsible for the boosted photocatalytic activity of nanocomposite catalyst. Furthermore, the present finding introduced an efficient photocatalyst with improved charge carrier kinetics for water purification applications.