Photocatalytic Dye Degradation Research Articles

Polyvinyl alcohol/polyethyleneimine grafted carbon oxynitride composite nanofiber membranes with the synergistical enhanced photocatalytic degradation and bactericidal performance

AbstractGraphitic carbon nitride (g‐C3N4) has received much attention as a metal‐free photocatalyst for dye degradation and sterilization. However, the low photocatalytic bactericidal activity and the difficulty in recycling have limited its applications. Here, oxidatively modified g‐C3N4 grafted with polyethyleneimine (PEI) nanofiber membranes (PVA/PEI‐OCN) was reported to enhance the photocatalytic activity. The modification by PEI grafting could reduce the recombination rate of photogenerated carriers and lead to more electrons for the photocatalytic reaction. In addition, electron spin resonance (ESR) results showed that the generation of reactive oxygen species (˙OH, ˙O2− and 1O2) were significantly enhanced in photocatalysis, leading to the significant enhancement of photocatalytic bactericidal activity and dye degradation. Furthermore, the PVA/PEI‐OCN nanofiber membranes prepared by electrospinning had smooth surfaces and uniform fiber formation, with an average diameter of 380 ± 60 nm. The tensile strength was about 73.5% higher than that of PVA nanofiber membranes. The inhibition diameter of PVA/PEI‐OCN‐4 against Escherichisa coli (E. coil) could reach 20 ± 0.2 mm, and the maximum degradation efficiency of methylene blue solution (10 mg/L) could reach 92.8% within 120 min. This work provided an effective paradigm for the rational design of metal‐free photocatalytic materials for elimination of bacterial and dye contamination.

Chemical spray deposited SnO2:MoO3 composite thin films for visible light photocatalytic dye degradation application

Chemical spray deposited SnO2:MoO3 composite thin films for visible light photocatalytic dye degradation application

Layered double hydroxide (LDH)-derived zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet for photocatalytic dye degradation and hexavalent chromium reduction

A new low-temperature facile chemical decomposition of layered double hydroxide (LDH) has been developed for the large-scale controlled synthesis of zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet. ZnAl-LDH/GO composite precursor was prepared via in situ growth of the LDH on the exfoliated GO nanosheets. Thermo-chemical decomposition of ZnAl-LDH/GO composite at 80 °C produced highly dispersed ZnO nanorods on GO nanosheets. Although, neat ZnAl-LDH produces ZnO nanoparticle aggregates in the absence of GO. The morphology and properties of ZnO nanorods/GO nanocomposite was studied by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The band gap engineering of the nanocomposite was evaluated by varying GO content. The ZnO/GO nanocomposites materials exhibited excellent photo-catalytic activity towards the degradation of methylene blue (MB) and Cr(VI) reduction under the irradiation of direct sunlight at ambient condition. GO plays a crucial role in the directional growth of nanorods and enhances the photocatalytic activity of ZnO nanorods via the synergistic hole formation and electron transfer effect for the potential remediation of waste water.

Photocatalytic Dye Degradation from Textile Wastewater: A Review

Photocatalytic Dye Degradation from Textile Wastewater: A Review

Role of N-Rich Coordination Environment in Metal–Organic Frameworks for Enhanced Photocatalytic Dye Degradation

Role of N-Rich Coordination Environment in Metal–Organic Frameworks for Enhanced Photocatalytic Dye Degradation

Phase transition influenced photocatalytic dye degradation capability of pure and Eu-doped CoMoO4 polymorphic nanostructures

ABSTRACT The efficient degradation of organic dyes via photocatalysis presents a critical environmental challenge, necessitating advancements in catalyst design and performance. This study investigates the potential of pure and Eu doped CoMoO4 polymorphic nanostructures in addressing this challenge. Our primary focus is on enhancing the efficiency and stability of photocatalysts under diverse condition by performing sol–gel synthesis. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV-visible) analysis and Raman analysis was employed to elucidate structural and morphological changes. Our results highlight the significant enhancement in photocatalytic activity achieved through phase transitions induced by Eu doping. This enhancement is attributed to the creation defect sites and the establishment of improved charge transfer pathways within the CoMoO4 nanostructures. By shedding light on the role of phase transition in photocatalysis, this study contributes valuable insights for the design of efficient and durable photocatalysts for environmental remediation application.

Reduced Work Function in Anatase ⟨101⟩ TiO2 Films Self-Doped by O-Vacancy-Dependent Ti3+ Bonds Controlling the Photocatalytic Dye Degradation Performance.

TiO2 has the proven capability of catalytically decomposing pollutants under light illumination, thereby embracing potential applications in wastewater management. The photocatalytic dye degradation activity is largely controlled by the optical band gap that dictates the extent of electron-hole pair generation via photon absorption, and the recombination kinetics of charges. In this context, the material's work function governs how easily the charge carriers can be transferred at the dye-adsorbed photocatalytically active sites. Accordingly, nanocrystalline TiO2 thin films are grown in the anatase phase with ⟨101⟩ orientation, using RF magnetron sputtering at 200 °C. Besides studying the film's structural morphology, optical band gap, and elemental composition, the electronic properties are extensively investigated. The work function of the material was controlled by varying the O-vacancy-dependent Ti3+ bonding configuration in the network. It has been demonstrated how the photocatalytic methylene blue dye degradation activity of the nanocrystalline TiO2 films of predominantly the anatase phase improves on reducing the sputtering pressure during deposition. At a low deposition pressure of 20 mTorr, a low work function of ∼4.2 eV of the film, resulting from the formation of a Ti3+-bond through the O vacancies in the network, potentially increases its carrier lifetime and delivers the superior photocatalytic activity (∼82.7% dye degradation with a rate constant of k ∼ 0.0073 min-1) via silently facilitating fast electron transfer from the photocatalyst to the dye in the aqueous solution. The higher stoichiometric film prepared at p = 40 mTorr exhibits an inferior photocatalytic activity (∼20.4% dye degradation with a rate constant of k ∼ 0.0009 min-1), as retarded by its higher work function of ∼4.62 eV, despite retaining a relatively low band gap. Thus, without using any heterojunction or extrinsically doped photocatalyst, the dye degradation can be controlled simply by reducing the work function of nanocrystalline TiO2 thin films via controlling the O-vacancy-dependent Ti3+ bonding in its self-doped network.

Carbon nitride impregnated non-woven jute post-industrial waste in photocatalytic degradation of textile dyes

Carbon nitride impregnated non-woven jute post-industrial waste in photocatalytic degradation of textile dyes

Photo-catalytic dye degradation potentials of Ag-Pd bimetallic nanoparticles synthesized from Vitex negundo.

Plant extracts are a great alternative to synthesizing nanoparticles of different metals and metal oxides. This green synthesis method has opened up numerous possibilities in various scientific domains. In present study, Leaf extract from Vitex negundo is a non-deciduous, long-lasting shrub from the Verbenaceae family is used as capping and reducing agents for the synthesis of silver and palladium nanoparticles. The characterization study UV-vis spectrophotometer analysis showed absorbance value around 320nm which confirming that Ag-Pd nanoparticles have been successfully obtained. Further, SEM is used to investigate the morphology of Ag-Pd NPs, which revealing their spherical and rod-like configuration, aggregation, and the size of the particles are obtained between 50 and 100nm. The successful synthesis of Ag-Pd NPs was further confirmed by the EDAX chart, which displayed the peak of Ag and Pd at bending energies between 0.5 and 1.5keV. According to the quantitative study, Ag and Pd ions found about 5.24 and 13.28%, respectively. In addition, surface studies with TEM confirming that synthesized Ag-Pd NPs are predominates with spheres structure morphologies, with sizes averaging 11.20nm and ranging from 10 to 20nm. Further, Ag-Pd nanoparticles was applied as potential photocatalyst materials to degrade methylene blue dye and found about 85% of the degradation efficiency within 150min of the sunlight exposure thus could be used as catalyst to removal of hazardous organic dye molecules.

Retraction Note: Influence of Fe doping on the photocatalytic dye degradation and H2 evolution properties of BiVO4 thin films under visible-light irradiation

Retraction Note: Influence of Fe doping on the photocatalytic dye degradation and H2 evolution properties of BiVO4 thin films under visible-light irradiation

Surface engineered recombinant Escherichia coli for the potential application of the cobalt contaminated wastewater treatment and the photocatalytic dye degradation

The novel recombinant Escherichia coli strain was construct through cell surface display for the treatment of cobalt contaminated wastewater and dye contaminated wastewater. First, structural analysis of known cobalt binding peptide was conducted and core binding sites were figured out which showing better cobalt binding ability. The cobalt peptides were attached to OmpC to construct cobalt adsorbing recombinant Escherichia coli. The recombinant strain efficiently absorbed and retrieved cobalt from cobalt wastewater by adsorbing 1895 µmol/g DCW of cobalt. Following adsorption, cobalt nanoparticles were synthesized through thermal decomposition of cobalt adsorbed recombinant strain at 500˚C. The nanoparticles exhibited noteworthy photocatalytic properties, demonstrating a substantial capacity for degrading dyes when used as a catalyst at a concentration of 10 mg/dl. These results presenting potential solutions for effective and environmentally friendly approaches to address cobalt and dye contaminated wastewater treatment process.

Photocatalytic dye degradation, H2 evolution, electrical and mechanical performances of mechano-synthesized multifunctional Bi2Te3 nanoparticles: Effect of milling time and thermal treatment

Photocatalytic dye degradation, H2 evolution, electrical and mechanical performances of mechano-synthesized multifunctional Bi2Te3 nanoparticles: Effect of milling time and thermal treatment

Facile construction of Bi2WO6/TiO2 microspheres heterojunction for boosting photocatalytic degradation of organic dyes

Flower-like Bi2WO6 microspheres and TiO2 spherical particles were prepared by a facile hydrothermal method without any surfactant or template. A unique Z-Scheme Bi2WO6/TiO2 heterojunction was successfully synthesized via a simple physical mixing method. The effect of mass ratio on the structure, morphology, optical properties, BET surface area and photocatalytic performance evaluated by degradation of organic dyes including Rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under solar irradiation was systemically investigated. When the mass ratio of Bi2WO6 to TiO2 was 1:4, the Bi2WO6/TiO2 composites exhibited the highest photocatalytic degradation efficiency, the highest degradation efficiency of RhB and MB reached 95.2 % and 89.3 %, which could be attributed to the construction of heterojunction structure between TiO2 and Bi2WO6. The optical absorption capacity of Bi2WO6/TiO2 composites was stronger than pure TiO2. Furthermore, the radical-quenching experiments proved that ·O2– and h+ played crucial roles in the photocatalytic reaction. The suitable band potential of Bi2WO6 (3.19 eV) and TiO2 (2.89 eV) revealed the Z-Scheme pathway and possible photocatalytic mechanism of Bi2WO6/TiO2 composites for organic dyes degradation. Thus, the direct Z-scheme Bi2WO6/TiO2 heterojunction effectively promoted separation of photogenerated electron-hole pairs, resulting in higher photocatalytic activity.

Earthworm excrete derived-enzyme enriched SnO2/g-C3N4 nanocomposite for near complete decomposition of toxic dye molecules

Enzymes derived from earthworm (Eudrilus eugeniae) excretes (vermiwash) were used as supporting bio-catalysts with SnO2/g-C3N4 nanocomposites for photocatalytic dye degradation of toxic organic dyes. The results were compared to those of the composite partners SnO2 and g-C3N4. The enzyme supported nanocomposite has superior photocatalytic efficiency of 95 %, 93 %, 83 % and 97 % against the test dyes Methylene Blue (MB), Malachite Green (MG), Methyl Orange (MO) and Rose Bengal (RB) whereas the partners SnO2 (62 %, 81 %, 36 % & 73 %) and g-C3N4 (76 %, 84 %, 80 % & 89 %) exhibited lower efficiencies. The enzymes phosphatase, amylase, urease and protease present in the synthesized nanocomposite play supporting role as co-catalyst in enhancing the photocatalytic ability of the nanocomposite. The mechanism involving the charge carrier recombination delay due to the formation of g-C3N4 sheets beneath the SnO2 particles is illustrated. The partnering mechanism with g-C3N4 having lower bandgap (2.8 eV) leads to a reduction in the bandgap from 3.5 eV for SnO2 to 2.6 eV for the nanocomposite making the nanocomposite as visible light responsive photocatalyst. The XRD, FTIR, SEM-EDX, UV–vis–NIR, XPS and DFT results support the discussion on photocatalytic mechanism. The near complete dye degradation is confirmed by phenotypic test on earthworm (Eudrilus eugeniae).

Morphological studies, photocatalytic degradation of organic dyes and anticancer potential of copper sulfide nanoparticles prepared from bis(diallyl dithiocarbamato)copper(II) complex

Bis(diallyl dithiocarbamato)copper(II) complex was synthesized and characterized by single crystal X-ray crystallography. The molecular structure revealed dimeric copper(II) complex consisting of two copper(II) ions that coordinate two molecules of diallydithiocarbamato anions in bidentate chelating modes and the centrosymmetrically related diallydithiocarbamato anions bridges the S-atom of the adjacent chelating ligand to formed square pyramidal geometry around the copper(II) ions. Copper sulfide nanoparticles were prepared at 160 °C by thermolysis of the copper(II) complex in dodecylamine (DDA), hexadecylamine (HDA), and octadecylamine (ODA) to study the effect of capping agents on the structural morphologies, photocatalytic properties, and anticancer potential of the as-prepared copper sulfides nanoparticles. Powder X-ray diffraction patterns confirmed Cu9S5 digenite crystalline phases for CuS-DDA and CuS-HDA while CuS-ODA is covellite crystalline phase. HRTEM images showed spherical particles with particle sizes in the range 2–25 nm. The copper sulfide nanophotocatalysts are efficient for the degradation of bromophenol blue with the highest photocatalytic efficiency of 95.14 % for CuS-DDA followed by CuS-HDA with 94.52 % and 93.95 % for CuS-ODA. The anticancer potentials of the compounds showed that CuS-HDA is the most potent with IC50 values of 1.22 µg/mL against HEK293 and 28.78 µg/mL against HeLa.

Magnetic zinc oxide/silica microbeads for the photocatalytic degradation of azo dyes

Photocatalysis is a promising technique for the complete degradation of azo dyes that are present in wastewater. In this work, a new photocatalyst in the form of ZnO/Fe3O4/SiO2 hybrid microbeads was fabricated for the photocatalytic degradation of methylene blue. The microbeads were synthesised through self-assembly and subsequent agglomeration of nanoparticles within an aqueous phase of a water-in-oil emulsion template. Photocatalytic degradation experiments were conducted through exposure of a methylene blue solution to UV light. The hybrid microbeads performed better than ZnO powder at the same initial dye and ZnO concentration because of higher adsorption and degradation. The initial concentration of dye solution and catalyst dosage have a significant impact on the degradation. Higher degradation is seen with lower initial dye concentration and higher catalyst dosage. The presence of magnetic nanoparticles within the beads allows for their full recovery and reuse for degradation experiments. Complete degradation of dye was achieved using the new ZnO/Fe3O4/SiO2 microbeads.

Multi-functional Copper Oxide Nanoparticles Synthesized using Lagerstroemia indica Leaf Extracts and their Applications

Developing multifunctional nanomaterials through environmentally friendly and efficient approaches is a pivotal focus in nanotechnology. This study aimed to employ a biogenic method to synthesize multifunctional copper oxide nanoparticles (LI-CuO NPs) with diverse capabilities, including antibacterial, antioxidant, and seed priming properties, as well as photocatalytic organic dye degradation and wastewater treatment potentials using Lagerstroemia indica leaf extract. The synthesized LI-CuO NPs were extensively characterized using UV–vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform-infrared spectroscopy (FT-IR). The colloid displayed surface plasmon resonance peaks at 320 nm, characteristic of LI-CuO NPs. DLS analysis revealed an average particle size of 93.5 nm and a negative zeta potential of -20.3 mV. FTIR and XPS analyses demonstrated that LI-CuO NPs possessed abundant functional groups that acted as stabilizing agents. XRD analysis indicated pure crystalline and spherical LI-CuO NPs measuring 36 nm in size. Antibacterial tests exhibited significant differential activity of LI-CuO NPs against both gram-negative (Escherichia coli, Salmonella typhimurium) and gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. In antioxidant tests, the LI-CuO NPs demonstrated a remarkable radical scavenging activity of 97.6% at a concentration of 400 μg/mL. These nanoparticles were also found to enhance mustard seed germination at low concentrations. With a remarkable reusability, LI-CuO NPs exhibited excellent photocatalytic performance, with a degradation efficiency of 97.6% at 150 μg/mL as well as a 95.6% reduction in turbidity when applied to wastewater treatment. In conclusion, this study presents environmentally friendly method for the facile synthesis of LI-CuO NPs that could potentially offer promising applications in biomedicine, agriculture, and environmental remediation due to their multifunctional properties.

Retraction Note: Visible light-enhanced photocatalytic dye degradation and hydrogen evolution performance of BiVO4 thin films prepared at various annealing temperatures

Retraction Note: Visible light-enhanced photocatalytic dye degradation and hydrogen evolution performance of BiVO4 thin films prepared at various annealing temperatures

Tm3+/Yb3+:NaGdF4 nanoparticles decorated g-C3N4/BiOBr0.75I0.25 multicomponent heterostructure: Structural, optical properties and UV-Visible-NIR responsive photocatalytic degradation of Rhodamine B and reduction of Cr(VI)

A wide solar spectral range responsive multicomponent heterostructure photocatalyst NGT/g-C3N4/BiOBr0.75I0.25 was successfully synthesized and used for the UV-visible-NIR photodegradation of the dye Rhodamine B and photoreduction of highly toxic hexavalent chromium ions. Our study shows that the heterostructure overcomes the drawbacks of limited visible-light absorption and fast charge recombination of g-C3N4. Herein, the incorporation of BiOBr0.75I0.25 extends the absorption in the visible region and endorses the separation rate of photogenerated charge carriers. Additionally, the upconversion nanoparticles NaGdF4: Tm/Yb (NGT) with its higher infrared light absorption capacity and characteristic emission spectral overlapping with absorption range of g-C3N4/BiOBr0.75I0.25 nanocomposite, further facilitates the photocatalytic activity of the NGT/g-C3N4/BiOBr0.75I0.25 heterostructured nanocomposite. Extensive structural, morphological, and compositional analysis was done using XRD, TEM, SEM, FE-SEM, XPS, and FTIR measurements. The PL emission, time-resolved decay, and electrochemical impedance spectroscopy were used to probe the separation rate of photogenerated electron-hole pairs and efficient energy transfer in NGT/g-C3N4/BiOBr0.75I0.25 heterostructured nanocomposite. The possible photocatalytic degradation mechanism was comprehensively proposed through a combination of UV-Vis absorption, Mott Schottky, and scavenger test analysis. The photodegradation efficiency of the heterojunction was 98%, which is much higher than the bare g-C3N4 (74%). Moreover, the heterostructure exhibited excellent long-term reusability, maintaining the photodegradation efficiency of 97.02% even after four consecutive degradation cycles, establishing it as a preferable material for photocatalytic dye degradation. Additionally, NGT/g-C3N4/BiOBr0.75I0.25 heterostructured nanocomposite also demonstated better performance for the photoreduction of Cr(VI) to Cr(III), achieving photocatalytic efficiency of 98.86% under acidic condition.

A green approach to synthesis of Ag-doped CeO2 nanorods embedded reduced graphene oxide nanocomposite for excellent photocatalytic and antimicrobial activity

In this paper, the Ag-doped cerium oxide nanorods embedded reduced graphene oxide (Ag@CeO2/rGO) nanocomposite was synthesized via Punica Granatum leaf extract for for photocatalytic degradation of methylene blue (MB) and 4-nitrophenol (4-NP). The microstructural results confirmed the successful decoration of Ag-doped CeO2 nanorods on rGO matrix. The photocatalytic properties, including photocatalytic degradation, charge transfer kinetics and photocurrent generation, are systematically investigated using electrochemical impedance spectroscopy (EIS), photocurrent transient response (PCTR) and open circuit voltage decay (OCVD). The results of photocatalytic dye degradation measurements indicated that Ag@CeO2/rGO nanocomposite is more effective than pristine CeO2 to degrade the MB dye, and the degradation rate reached 100 % in 60 min. The decomposition of MB with Ag@CeO2/rGO nanostructure followed first-order reaction kinetics with a reaction rate constant (Ka) of 0.0198 min−1. The EIS and OCVD measurements revealed that the Ag doping and incorporation of rGO could suppress the recombination probability in CeO2 by the separation of photo-generated electron–hole pairs, which leads to the enhanced photocurrent generation and photocatalytic activity. The photocurrent density of Ag@CeO2/rGO, CeO2/rGO and pristine CeO2 are 215, 167.4 and 98.8 mAcm−2, respectively.