Photocatalytic Dye Degradation Research Articles

Degradation of rhodamine B dye under visible and solar light on zinc oxide and nickel-doped zinc oxide thin films

The kinetic investigation of rhodamine B dye's photocatalytic degradation, chosen as a model pollutant, was conducted at room temperature using Zinc oxide (ZnO) and nickel-doped zinc oxide (Zn0.97Ni0.03O) photocatalysts synthesized through the spray pyrolysis method. XRD analysis confirmed the formation of hexagonal ZnO and Zn0.97Ni0.03O films, with crystallite sizes ranging from 19 to 29 nm and varying in mean average grain size from 72 nm to 88 nm. The surface morphology of the Ni-doped ZnO films was influenced by nickel doping, observed through SEM and TEM micrographs, revealing a dense structure of spherical-shaped crystals. Light transmission and optical band gap energy of the films ranged between specified values, ranging from 3.27 to 3.24 eV. The degradation process was assessed under various conditions, including different light sources (UV lamp and solar irradiation), pH levels, and substrate concentrations. Degradation followed a pseudo-first-order kinetic model, with rate constants (k) and half-life times (t1/2) calculated accordingly. The degradation efficiency of undoped ZnO and ZnO doped with nickel decreased with increasing concentration under UV irradiation from (0.1–0.5 M) under UV irradiation decreased from (34.29–45.02) (49.61–56.61), while under visible light are (40–45.07 %) (58.46–60.24 %), removal rates ranged within specific percentages. The porous Zn0.97Ni0.03O synthesized at 0.5 M exhibited the highest photocatalytic efficiency due to its enhanced crystallinity, resulting in degradation rates of 9.22 and 11.22 × 10−3 min−1 and half-life times of 75.18 and 61.77 min at 90 min specified for both UV and solar light irradiations, respectively. Acidification of the reaction medium accelerated the photocatalytic degradation kinetics, while alkalization slowed it down. These findings mark a significant advancement in the utilization of oxide semiconductors for water pollutant degradation under natural sunlight.

Optimization and modelling of magnesium oxide (MgO) photocatalytic degradation of binary dyes using response surface methodology

Textile industry dye effluent contains a mixture of different kinds of dyes. Many times, photocatalysis is targeted as a solution for the treatment of dye effluent from the textile industry. Many researches have been published related to the photocatalysis of single textile dyes but in the real-world scenario, effluent is a mixture of dyes. Magnesium oxide (MgO) is used as a photocatalyst to treat a mixture (binary solution) of Methylene blue (MB) and Methylene violet (MV) along with individual MB and MV dyes in this article. MgO shows remarkable photocatalytic activity at about 93 and 88% for MB and MV dye in binary solution within 135 min. Furthermore, to study the influence of process parameters, experiments are designed with the help of the central composite design (CCD), and Response surface methodology (RSM) is used to study the interactions between parameters. For this study, five parameters are selected i.e., Photocatalyst dosage, initial concentration of both dyes, time of exposure to the light source, and pH of the binary solution. The photocatalytic process is also optimized and finally optimization of process parameters is validated with an experiment. The result of the validation experiment is very close to the predicted photocatalytic activity.

Natural sunlight energy harvesting using NiAl2O4@N-rGO hetero-junction for photocatalytic degradation of crystal violet dye: Kinetic and mechanistic insights

In this study, NiAl2O4 (NA) was synthesized by the co-precipitation route and its hetero-junctions were fabricated with N-doped reduced graphene oxide (N-rGO) through the ultra-sonication method. The structural, morphological, magnetic, optical and photocatalytic properties of synthesized NA, N-rGO, and the NA@N-rGO 1–4 hetero-junctions characterized by XRD, FTIR, SEM, VSM, PL and UV–visible spectroscopy, respectively. XRD results showed that crystallite size decreases from 25.01 nm (NA) to 15.20 nm for NA@N-rGO-4 and porosity increases up to 77.7 % for NA@N-rGO-4 making it remarkable for photocatalytic applications and FTIR results confirmed the formation of N-rGO as well as its successful integration into NA matrix, resulting in the formation of hetero-junctions. Magnetic properties were investigated using a vibrating sample magnetometer (VSM), revealing distinctive S-shaped hysteresis loops at 25 °C for both NA and N-rGO, as well as the NA@N-rGO 1–4 hetero-junctions and magnetic saturation decreases with an increase in N-rGO content as for NA@N-rGO-4 Ms drops to 0.0038 emu/g. Notably, the bandgap of NA@N-rGO-4 hetero-junction was effectively reduced from 3.0 eV (in the case of NA) to 2.1 eV, resulting in a discernible decrease in photoluminescence (PL) intensity and increase in e--h+ pair separation. Under visible light, NA@N-rGO-4 exhibited a remarkable 94.68 % efficiency in crystal violet (CV) dye degradation within just 90 min, outperforming NA's 59.05 % degradation efficiency and OH. Radicals play a major contribution to the degradation of dye. The optimization of degradation capabilities was achieved through the manipulation of catalyst dosage, dye concentration and varying pH values for the degradation of CV dye. NA@N-rGO-4 hetero-junction demonstrates the considerable potential for efficient dye degradation in wastewater under visible light, owing to its exceptional catalytic performance.

Investigating dual-functional Al-doped stannic oxide nanorods towards photodegradation of real industry wastes and dye-sensitized solar cell application: An experimental and theoretical interpretation

In this work, we demonstrate a uniquely designed Tin (IV) Oxide (SnO2)-based nanomaterials for energy and environmental applications. Here, the Al-doped SnO2 nanorods (NR) at various concentrations ranging from 3 wt% to 9 wt% carried out following facile co-precipitation technique which induced synergic structural, optical and electrical properties in resulting products. Further, the Al-incorporation induced considerable changes to the structural, optical, and electrical characteristics turning SnO2 nanorods to Al-SnO2 nanocubes (NCs). Resulting changes from nanorod to nanocubes were closely monitored using various characterization techniques, which were then effectively utilized for photocatalytic degradation of important textile industry dyes, encompassing both cationic (MB, CV) and anionic (EBT) types. Optimal Al-doped SnO2 NC (6 wt%) demonstrated significant degradation efficiencies for organic pollutant and textile industry effluents under direct sunlight exposure. On the other hand, combination of optical and electrical properties was utilized in dye-sensitive solar cells (DSSCs) to achieve noteworthy efficiency of 6.33%, surpassing that of previous reported SnO2-based nanostructures. These exceptional performance nanomaterials can be attributed to the optimized morphology of the nanocubes and the reduction of the band gap from 3.24 eV to 2.75 eV facilitated by the introduction of aluminum dopant. Furthermore, synergic combination has also improved visible light excitation, substantially decreased resistance to charge carrier transfer phenomenon, improved the charge carrier concentration, as well as considerably decreased the electron/hole recombination rate. Therefore, presence of Al in SnO2 nanostructure has considerably improved the opto-electrical properties that were interpreted following theoretical studies. Therefore, study gives simple nanomaterials having both the photodegradation and dye-sensitive solar cell (DSSC) performance of the SnO2 nanostructure, as a cost-effective energy conversion and water pollution remediation tool for the near future.

Novel existence of Mn and Cu in WO3 nanostructures for promising photocatalytic activity against MB dye and Levofloxacin antibiotic

To enhance photocatalytic degradation of MB dye and Levofloxacin antibiotic, facile coprecipitation strategy was used to synthesize pure WO3 and novel Mn-Cu codoped WO3 nanostructures. The synthesized nanostructures were probed by XRD, SEM, EDX, FTIR, XPS, BET, TEM, PL and UV–vis spectra to analyze optical and morphological properties. Pure WO3, Mn2%-Cu1%-WO3, Mn2%-Cu3%-WO3, Mn2%-Cu5%-WO3 and Mn2%-Cu7%-WO3 were optimized novel materials that were used for water treatment against model impurities. Optical properties of pure WO3 were enhanced to successfully increase the photocatalytic degradation of principal water pollutants. Over a time span of 175 minutes, 86.7% of MB dye was degraded and 75.9% Levofloxacin was degraded by an average of 49 nm and 2.16 eV bandgap Mn2%-Cu5%-WO3 optimal sample. Due to smaller particle size, surface to volume ratio gave more active sites to the photocatalysts for pollutants degradations. Interestingly, just 15% degradation loss was observed after consecutive 6 cycles against the degradation of MB dye and 9.1% loss against Levofloxacin medicine after 6 photocatalytic runs. XPS spectra offered crucial insights into the elemental composition and chemical states of the Mn-Cu-WO3 nanostructures. According to these findings, Mn-Cu-WO3 can be used as a good candidate with long time stability against pollutants degradations.

Catalysing a sustainable future: Harnessing solar energy with novel Co3O4@VO2 nanocomposites for enhanced photocatalytic hydrogen generation and dye degradation

This study focuses on the hydrothermal synthesis and characterization of Concentration dependent Co3O4@VO2 nanocomposites with varying molar ratios of Co3O4 to VO2 (2:1, 1:1, and 1:2) for efficient hydrogen generation and dye degradation. The structural and morphological characteristics of the prepared nanocomposites were analysed using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Crystallographic analysis using XRD confirmed the formation of crystalline Co3O4 with a monoclinic structure, while the presence of VO2 was identified by characteristic peaks in the XPS. Microscopic analysis using SEM and TEM revealed well-dispersed nanocomposites with nanoscale dimensions. Photocatalytic activities were evaluated for hydrogen evolution and dye degradation, with the nanocomposite featuring a 2:1 ratio of Co3O4 to VO2 (CV-21) demonstrating significantly enhanced performance. CV-21 exhibited a lower onset potential and higher current density for hydrogen evolution (2270μmol/h/g), indicating improved photocatalytic activity. Additionally, it displayed rapid and superior dye degradation (93% within 10 min) under sunlight compared to Victoria blue B (VBB) dye. The Co3O4@VO2 nanocomposites, particularly CV-21, demonstrate enhanced photocatalytic performance for hydrogen generation and dye degradation compared to pristine VO2 and Co3O4. This improvement possibly due to synergistic effects between Co3O4 and VO2, optimized structural characteristics, and improved interfacial properties in the nanocomposite structure. These findings highlight the promising potential of Co3O4@VO2 nanocomposites, particularly CV-21, for environmental remediation applications.

An effective approach to improve photocatalytic dye degradation and electrochemical properties of MoO3 nanoparticles

An effective approach to improve photocatalytic dye degradation and electrochemical properties of MoO3 nanoparticles

Synthesis and characterization of alpha and beta cobalt hydroxide nanostructures for photocatalytic dye degradation and supercapacitor applications

Alpha and beta cobalt hydroxide nanostructures were synthesized by hydrothermal method and characterized using X-ray diffraction and electron microscopy. The turbostatic alpha-Co(OH)2 has large interlayer spacing compared to the beta-Co(OH)2 and is less explored in the literature. Both nanostructures were efficient in degrading methylene blue dye in the presence of visible light. Under identical conditions, the rate constant of photocatalytic dye degradation in the presence of alpha and beta cobalt hydroxide was calculated as 60.22 × 10−3 min−1 and 19.05 × 10−3 min−1, respectively, which is highest when compared to the previous reports. The superior activity of alpha-Co(OH)2 when compared to beta-Co(OH)2 is also demonstrated in this work. Additionally, a Csp value of 137 F/g and 2.4 F/g, respectively, at a current density of 1 A/g, was obtained from the GCD analysis of devices made using alpha-Co(OH)2 and beta-Co(OH)2. A higher cyclic stability and power density were observed for alpha-Co(OH)2 when compared to beta-Co(OH)2. The findings suggest that alpha and beta cobalt hydroxide nanostructures hold promise as effective catalysts for dye degradation and potential materials for high-performance supercapacitors. Further investigations into the unique properties of the relatively superior alpha-Co(OH)2 could lead to advancements in environmental remediation and energy storage technologies.

Visible light-induced photocatalytic degradation of methylene blue dye using pure phase bismuth ferrite nanoparticles

The degradation of organic dyes in wastewater has become a significant environmental issue, requiring the development of degradation technologies that are both effective and environmentally friendly. The present study employed the sol-gel approach to synthesize nanoparticles of phase pure bismuth ferrite (BiFeO3). The nanoparticles were assessed for their ability to efficiently degrade methylene blue (MB) dye, especially under visible light irradiation. The X-ray diffractogram (XRD) confirmed the formation of BiFeO3 nanoparticles, with an average crystallite size of 48 nm. The material's band gap, with a value of 1.84 eV, demonstrates its capacity to effectively absorb light, including wavelengths within the visible spectrum. Scanning electron microscopy (SEM) was used to identify porous aggregated particles. Both Raman and Fourier transform infrared spectroscopy (FTIR) confirm the successful synthesis of pure BiFeO3 in the desired phase. The BiFeO3 photocatalyst exhibited a significant surface area and isotherms of type IV, a characteristic typically observed in mesoporous materials, as determined by the Brunauer-Emmett-Teller (BET) analysis. The efficacy of BiFeO3 nanoparticles in facilitating the decomposition of MB in a water-based solution was evaluated by visible light photocatalysis. An efficiency degradation of 98.49 % was recorded for MB within 2 h.

Temperature-controlled morphology and enhanced functionalities of hydrothermally synthesized SrFe2O4 nanostructures for multifaceted applications

In this study, we investigate the effect of synthesis temperature on the morphology and properties of spinel strontium ferrite (SrFe2O4) nanostructures, synthesized using a surfactant-free hydrothermal method. We demonstrate that by varying the temperature from 85 °C to 160 °C, we can control the morphology of SrFe2O4, transitioning from nanoribbons to dendritic structures, and finally to hexagonal nanoplatelets. These morphological changes correspond to significant enhancements in both magnetic and photocatalytic performance. The saturation magnetization (Ms) notably increases by up to 70 % at higher synthesis temperatures. Additionally, these nanostructures show improved efficiency in photocatalytic degradation of methylene blue dye, indicating their potential for environmental remediation. The dielectric properties of the various morphologies were also characterized, suggesting applications in electronics and energy storage. This study establishes a clear link between synthesis conditions, resulting structures, and functional performance in SrFe2O4 nanostructures, contributing to the development of advanced materials.

Biosynthesis of Ag-Doped CuO Nanoparticles Using Heracleum persicum Extract for Enhanced Antibacterial and Photocatalytic Dye Degradation Properties

Biosynthesis of Ag-Doped CuO Nanoparticles Using Heracleum persicum Extract for Enhanced Antibacterial and Photocatalytic Dye Degradation Properties

Synthesis of Group IIB and IVB Metal Complexes of 3‐Nitroaniline for Photocatalytic Degradation of Organic Dyes

AbstractIn the current research, new metal complexes have been synthesized by using the greener synthetic approach in which 3‐Nitroaniline reacts with the elements of group‐IIB and group‐IVB. According to this method, ligand and metals were dissolved in 1,4‐dioxane and stirred at room temperature for a specific time period. The method for the preparation of metal‐base complexes is quite simple and cost‐effective. To identify the synthesized compounds various physio‐chemical analytical techniques were used such as Melting point, FT‐Raman Spectroscopy, FT‐IR Spectroscopy, Thermogravimetric analysis, and Scanning electron microscope (SEM) that provide significant data about the general structural characteristics of synthesized compounds. The percentage degradation efficiency of synthetic dyes was obtained as 57 %, 66 %, and 97 % using the synthesized compounds as photocatalysts. A statistical tool, RSM was used for the optimization of parameters (Concentration of Dye, Dose of Catalyst, and contact time).

Visible Light-Induced Photocatalytic Degradation of Methylene Blue Using Copper-Doped Carbon Dots One-Step Derived from CCA-Wood

Developing novel eco-friendly broad-spectrum visible light photocatalysts for dye removal is one of the urgent problems for water treatment. Here, copper-doped carbon dots (CDs) were reported to be directly fabricated from chromated copper arsenate (CCA) wood waste for the photocatalytic degradation of the methylene blue dye. The properties of the resulting CDs were thoroughly characterized and analyzed, preceding an investigation into the adsorption kinetics of dye degradation. The kinetic study showed that reactant concentration was the rate-limiting factor. The obtained CDs showed a 151 mg/g photocatalytic degradation capacity. Comparing pure CDs to CDs/TiO2 composites, the former demonstrated higher photodegradation efficiency. This superiority can be attributed to the synergistic action of adsorption and photocatalytic degradation working in tandem. This study prepared Cu doped CDs and elucidated the photocatalysis mechanism of methylene blue degradation by CDs. The photodegradation of organic dyes through CDs derived from waste CCA wood emerges as an eco-friendly, facile, and highly efficient method.

Optical and UV Shielding Properties of Inorganic Nanoparticles Embedded in Polymethyl Methacrylate Nanocomposite Freestanding Films.

Polymethyl methacrylate (PMMA) is an interesting polymer employed in various applications due to its outstanding properties. However, its electrical and mechanical properties can be further improved by incorporating nanoparticles, and in particular, PMMA nanocomposite with nanoparticles provides various multifunctional properties. This work reports PMMA nanocomposite preparation and structural and optical characterizations incorporating carbon nanotubes (CNTs), TiO2 nanoparticles, and carbon quantum dots (CQDs). CNT/PMMA, TiO2/PMMA, and CQD/PMMA nanocomposite freestanding films were prepared using a simple solution method. Various properties of the prepared composite films were analyzed using scanning electron microscopy, X-ray diffraction, photoluminescence, Fourier transform infrared, and UV-Vis and Raman spectroscopy. Optical parameters and photocatalytic dye degradation for the films are reported, focusing on the properties of the materials. The CNT/PMMA, TiO2/PMMA, and CQD/PMMA films achieved, respectively, good electrical conductivity, photodegradation, and fluorescence compared with other composite films.

Green Synthesis of Platinum Nanoparticles Using Polymer Bio-reduction Approach and Their Photocatalytic Organic Dye Degradation

Green Synthesis of Platinum Nanoparticles Using Polymer Bio-reduction Approach and Their Photocatalytic Organic Dye Degradation

Ag-doped TiO2 with Tuneable Ag⁰ and Ag+ for Enhanced Photocatalytic Degradation of RR4 Dye

Ag-doped TiO2 with Tuneable Ag⁰ and Ag+ for Enhanced Photocatalytic Degradation of RR4 Dye

Peroxymonosulfate enhanced photocatalytic degradation of organic dye by metal-free TpTt-COF under visible light irradiation

Recently, the activation of persulfate (PDS) by non-metallic photocatalysts under visible light has attracted significant interest in applications in environmental remediation. This study presents a pioneering investigation into the combined application of the TpTt-COF and PMS for visible light degradation of organic dyes. Synthesized orange TpTt-COF monomers exhibit exceptional crystallinity, a 2D structure, and notable stability in harsh conditions. The broad visible light absorption around a wavelength of 708 nm. The TpTt-COF emerges as a promising candidate for photocatalytic dye degradation. The study addresses high charge recombination in the TpTt-COF, highlighting the crucial role of its electron donor and acceptor for the PMS activation. Comparative analyses against traditional photocatalytic materials, such as the metal-free carbon-based material g-C3N4 and transition metal-containing TiO2, demonstrate TpTt-COF's superior performance, generating diverse free radicals. In simulated experiments, the TpTt-COF's degradation rate surpasses PMS-combined g-C3N4 by 13.9 times. and 1.6 times higher than the TpTt-COF alone. Remarkably, the TpTt-COF maintains high activity under harsh environments. Investigations into the degradation mechanism and the TpTt-COF's reusability reveal its efficiency and stability. Under visible light, TpTt-COF facilitates efficient electron–hole separation. Combining the TpTt-COF with PMS produces various radicals, ensuring effective separation and a synergistic effect. Radical quenching experiments confirm the pivotal role of O2-· radicals, while ·OH and SO4-· radicals intensify the degradation. After five cycles, TpTt-COF maintains an impressive 83.2% degradation efficiency. This study introduces an efficient photocatalytic system mediated by PMS and valuable insights into governing mechanisms for organic pollutant degradation in water environments.

Aqua-Mediated Hydrothermal Synthesis in the Production of a g- C3N4/TiO2 Composite for Photocatalytic Degradation of RR4 Dye

Aqua-Mediated Hydrothermal Synthesis in the Production of a g- C3N4/TiO2 Composite for Photocatalytic Degradation of RR4 Dye

Ti3C2Tx MXene decorated with NiMnO3 / NiMn2O4 nanoparticles for simultaneous photocatalytic degradation of mixed cationic and anionic dyes

The present report investigated the different mass ratios of Ti3C2Tx MXene decorated NiMnO3 / NiMn2O4 nanoparticles and their enhancement of photocatalytic performance. The NiMnO3 / NiMn2O4 - Ti3C2Tx MXene nanocomposites were synthesized by a simple electrostatic self-assembly method. The physicochemical properties of nanocomposites were analyzed by XRD, SEM, and FESEM with EDAX, FTIR, PL, and UV-Visible spectrometer. The rhombohedral / cubic spinel structure of NiMnO3 / NiMn2O4 was confirmed by the XRD. The SEM and FESEM morphology show that spherical NiMnO3 / NiMn2O4 nanoparticles were decorated on the Ti3C2Tx MXene sheets and also present on the inside of the Ti3C2Tx MXene sheets. The average diameter of NiMnO3 / NiMn2O4 nanoparticles (46 nm) and the interlayer spacing of Ti3C2Tx MXene sheets (56 nm) were measured from FESEM analysis. The energy bandgap of NiMnO3 / NiMn2O4 - MXene nanocomposites was determined as ranging from 1.2 eV to 0.8 eV. The Ni, Mn, O, Ti, C, and F elemental compositions of the composites were analyzed by the EDAX. The effective photo-generated electron transferring from NiMnO3 / NiMn2O4 to Ti3C2Tx MXene was established by the PL quenching of NiMnO3 / NiMn2O4. The 100 % degradation efficiency was achieved in methylene blue (MB). The mixed dye degradation rates achieved for Rhodamine B (RhB), methyl orange (MO), and methylene blue (MB) for 90 %,72 %, and 100 % after 50 min in the presence of NiMnO3 / NiMn2O4 -Ti3C2Tx MXene (20 wt %). According to a scavenger experiment, the predominant species actively involved in the photodegradation process were revealed to •OH and •O2-.

Synthesis of novel TiO2/CeFeO3 heterojunction using Mugwort (Artemisia vulgaris) leaves extracts with enhanced photocatalytic activity under visible light irradiation

TiO2 is a low-cost and biocompatible material with high oxidizing ability. However, their photocatalytic activity is limited to UV light irradiation. In this research, for the first time, a novel TiO2/CeFeO3 heterojunction was synthesized by the green synthesis method using an aqueous fraction of Artemisia vulgaris leaf extracts. TiO2/CeFeO3 shows enhanced photocatalytic performance under visible light irradiation. The vibrational, structural, optical, and compositional properties of TiO2/CeFeO3 were characterized. The as-prepared TiO2/CeFeO3 has spherical-shaped particles and shows a significantly diminished bandgap energy (3.25 eV to 2.75 eV). The photocatalytic performance of TiO2/CeFeO3 was investigated to degrade malachite green (MG) with an efficiency of up to 93.53% under its optimum dose. TiO2/CeFeO3 shows stable photocatalytic performance until the fourth cycle. The kinetics of the photodegradation of MG followed the pseudo-first-order reaction with a rate constant (kapp) of 2.14×10−2 min−1. The enhanced photocatalytic activity of TiO2/CeFeO3 was attributable to the creation of heterojunction, which suppresses the recombination rate of photogenerated electron-hole validated by the photoluminescence analysis. This work presents an eco-friendly approach to synthesizing novel heterojunction material with enhanced photocatalytic dye degradation.