Facile synthesis of ZnO/CuO/Eu heterostructure photocatalyst for the degradation of industrial effluent

Zinc oxide-based ternary heterostructure ZnO/CuO/Eu(1%, 3%, and 5% of Eu) nanoparticles were effectively produced by employing Vigna unguiculata (cowpea)waste skin extract as fuel in a simple one-pot combustion process. The as-synthesized heterostructure was analyzed by X-ray diffraction studies, ultraviolet-visible spectroscopy, Fourier Transform Infrared Spectroscopy, Field Emission Scanning Electron Microscopy, and High-Resolution Transmission Electron Microscopy techniques. Besides, the photocatalytic degradation efficiency of the as-obtained ternary nanocomposite was evaluated under UV light for the degradation of model organic pollutants including methylene blue (MB), Rhodamine-B (RB), and an effluent sample collected from the textile industrial waste. During this study, the effect of a variety of parameters on the photodegradation activity of the photocatalysts has been thoroughly evaluated, such as light source, catalyst dose, irradiation period, dye concentration, solution pH, etc. Under UV irradiation(100 mins), the ternary ZnO/CuO/Eu photocatalyst demonstrated excellent degradation activity of ～99 and ～93% for MB and RB, respectively, while for the industrial effluent, a decent degradation activity of 42% has been recorded. Further experiments have revealed a pH and concentration-dependent photocatalytic behavior of the heterostructure photocatalyst. Therefore, the results suggest that the heterostructure photocatalyst can be potentially applied for wastewater treatment and other environmental applications.     

Synthesis, characterization and photocatalytic property of AgBr/BiPO4 heterojunction photocatalyst

A novel heterojunction AgBr/BiPO(4) photocatalyst was synthesized with the hydrothermal method. The photocatalyst was characterized by X-Ray powder Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectrscopy (XPS) and Diffuse Reflectance Spectroscopy (DRS). The XRD, SEM-EDS, TEM and XPS analyses indicated that the heterojunction structure formed during the process of hydrothermal treatment. The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue dye (MB). The results indicated that the AgBr/BiPO(4) heterojunction exhibited a much higher photocatalytic activity than the pure BiPO(4). The mechanism of the enhancing AgBr/BiPO(4) heterojunction's photocatalytic activity was discussed. It was also found that the photocatalytic degradation of MB over AgBr/BiPO(4) heterojunction photocatalysts followed the pseudo-first-order reaction model.     

Phyto-Extract-Mediated Synthesis of Silver Nanoparticles Using Aqueous Extract of Sanvitalia procumbens,and Characterization,Optimization and Photocatalytic Degradation of Azo Dyes Orange G and Direct Blue-15

Green synthesis of silver nanoparticles (AgNPs) employing an aqueous plant extract has emerged as a viable eco-friendly method. The aim of the study was to synthesize AgNPs by using plant extract of Sanvitalia procumbens (creeping zinnia) in which the phytochemicals present in plant extract act as a stabilizing and reducing agent. For the stability of the synthesized AgNPs, different parameters like AgNO₃ concentration, volume ratios of AgNO₃, temperature, pH, and contact time were studied. Further, AgNPs were characterized by UV–visible spectroscopy, FT-IR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), and EDX (Energy Dispersive X-ray Spectrometer) analysis. FT-IR analysis showed that the plant extract contained essential functional groups like O–H stretching of carboxylic acid, N–H stretching of secondary amides, and C–N stretching of aromatic amines, and C–O indicates the vibration of alcohol, ester, and carboxylic acid that facilitated in the green synthesis of AgNPs. The crystalline nature of synthesized AgNPs was confirmed by XRD, while the elemental composition of AgNPs was detected by energy dispersive X-ray analysis (EDX). SEM studies showed the mean particle diameter of silver nanoparticles. The synthesized AgNPs were used for photocatalytic degradation of Orange G and Direct blue-15 (OG and DB-15), which were analyzed by UV-visible spectroscopy. Maximum degradation percentage of OG and DB-15 azo dyes was observed, without any significant silver leaching, thereby signifying notable photocatalytic properties of AgNPs.     

Evaluation of the Photocatalytic Properties of Copper Oxides/Graphene/TiO2 Nanoparticles Composites

Easy and cost-efficient modifications of titanium dioxide nanoparticles that improve their efficiency in the visible light domain represent a continuous and challenging research topic. In addition, the effect of graphene on the overall photocatalytic process is still debated. Consequently, herein, we prepared a series of TiO₂ nanoparticle-based composites with different copper oxide mass content (1–3%) and co-doped with graphene of different oxidation degrees. Different characterization techniques were used to analyze the structural and physico-chemical properties of the obtained composites: Scanning Electron Microscopy (SEM)/Transmission Electron Microscopy (TEM)/Energy-dispersive X-ray spectroscopy (EDX) analysis, X-ray powder diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance was evaluated by the degradation of methylene blue under both UVA and visible light irradiation. The nanocomposites show very good photocatalytic activity independent of the presence of reduced graphene oxide, due to the Cu₂O/CuO-TiO₂ heterojunctions. This finding has been confirmed by the very efficient visible-light-driven degradation of amoxicillin and ciprofloxacin.     

Sunlight Photocatalytic Performance of ZnO Nanoparticles Synthesized by Green Chemistry Using Different Botanical Extracts and Zinc Acetate as a Precursor

In this work, the assessment of Azadirachta indica, Tagetes erecta, Chrysanthemum morifolium, and Lentinula edodes extracts as catalysts for the green synthesis of zinc oxide nanoparticles (ZnO NPs) was performed. The photocatalytic properties of ZnO NPs were investigated by the photodegradation of methylene blue (MB) dye under sunlight irradiation. UV-visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Thermogravimetric (TGA), and Brunauer-Emmett-Teller analysis (BET) were used for the characterization of samples. The XRD results indicate that all synthesized nanoparticles have a hexagonal wurtzite crystalline structure, which was confirmed by TEM. Further, TEM analysis proved the formation of spherical and hemispherical nanoparticles of ZnO with a size in the range of 14–32 nm, which were found in aggregate shape; such a size was well below the size of the particles synthesized with no extract (~43 nm). ZnO NPs produced with Tagetes erecta and Lentinula edodes showed the best photocatalytic activity, matching with the maximum adsorbed MB molecules (45.41 and 58.73%, respectively). MB was completely degraded in 45 min using Tagetes erecta and 120 min using Lentinula edodes when subjected to solar irradiation.     

Cation Incorporation and Synergistic Effects on the Characteristics of Sulfur-Doped Manganese Ferrites S@Mn(Fe2O4) Nanoparticles for Boosted Sunlight-Driven Photocatalysis

In the present work, sulfur-doped manganese ferrites S@Mn(Fe₂O₄) nanoparticles were prepared by using the sol-gel and citrate method. The concentration of sulfur varied from 1 to 7% by adding Na₂S. The samples were characterized by performing Fourier Transformed Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Ultraviolet–Visible spectroscopy (UV–Visible). The synthesized sulfur-doped manganese ferrites were applied to evaluate the photocatalytic degradation of the dyes. Further, the degradation studies revealed that the nanoparticles successfully degraded the methylene blue dye by adding a 0.006 g dose under the sunlight. The sulfur-doped manganese ferrite nanoparticles containing 3% sulfur completely degraded the dye in 2 h and 15 min in aqueous medium. Thus, the ferrite nanoparticles were found to be promising photocatalyst materials and could be employed for the degradation of other dyes in the future.     

油水自组装制备Ag@AgBr/BiOBr高效可见光催化剂

采用油水自组装法制备Ag@Ag Br表面修饰三维花状结构Bi OBr复合光催化剂(Ag@Ag Br/Bi OBr),利用XRD、SEM、TEM、EDX、DRS、XPS、PL及EIS等手段对光催化剂的结构和性能进行了表征,并研究了可见光下降解亚甲基蓝(MB)的催化性能。研究表明:Ag@Ag Br粒径约为20 nm,均匀分散在花状微球Bi OBr表面上;贵金属Ag的表面等离子体效应可显著增强可见光利用率,并有效促进光生电子空穴对的分离,Ag@Ag Br(15wt%)/Bi OBr光催化剂展现出最优的催化活性,可见光照射30 min对MB的降解率将近90%,淬灭实验表明·O2-,h+和Br0均为活性物种。结合理论分析与实验结果提出复合光催化剂的降解机理。     

油水自组装制备Ag@AgBr/BiOBr高效可见光催化剂

采用油水自组装法制备Ag@AgBr表面修饰三维花状结构BiOBr复合光催化剂(Ag@AgBr/BiOBr),利用XRD、SEM、TEM、EDX、DRS、XPS、PL及EIS等手段对光催化剂的结构和性能进行了表征,并研究了可见光下降解亚甲基蓝(MB)的催化性能.研究表明:Ag@AgBr粒径约为20nm,均匀分散在花状微球BiOBr表面上;贵金属Ag的表面等离子体效应可显著增强可见光利用率,并有效促进光生电子空穴对的分离,Ag@AgBr(15wt%)/BiOBr光催化剂展现出最优的催化活性,可见光照射30min对MB的降解率将近90%,淬灭实验表明·O₂^-,h⁺和Br⁰均为活性物种.结合理论分析与实验结果提出复合光催化剂的降解机理.     

Characterization, activity and mechanisms of a visible light driven photocatalyst: Manganese and iron co-modified TiO2 nanoparticles

An attempt was made to prepare Mn,Fe-codoped nanostructured TiO₂ photocatalyst for visible light assisted degradation of an azo dye (methylene blue) in aqueous solutions by a sol-gel process. The asprepared nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectra (PL) techniques. The photocatalytic activity of Mn,Fe-codoped TiO₂ catalyst was evaluated by measuring degradation rates of methylene blue (MB) under visible light. The results showed that doping with the manganese and iron ions significantly enhanced the photocatalytic activity for MB degradation under visible light irradiation. This was ascribed to the fact that a small amount of manganese and iron dopants simultaneously increased MB adsorption capacity and separation efficiency of electron-hole pairs. The results of DRS showed that Mn,Fe-codoped TiO₂ had significant absorption between 400 and 500 nm, which increased with the increase of manganese ion content. It is found that the stronger the PL intensity, the higher the photocatalytic activity. This could be explained by the points that PL spectra mainly resulted from surface oxygen vacancies and defects during the process of PL, while surface oxygen vacancies and defects could be favorable in capturing the photoinduced electrons during the process of photocatalytic reactions, so that the recombination of photoinduced electrons and holes could be effectively inhibited.     

Ionic liquid assisted synthesis of flowerlike Cu2O micro-nanocrystals

Novel flowerlike Cu2O micro-nanocrystals were prepared by a greener reductive reaction of cupric acetate monohydrate with ethylene glycol in aqueous solutions of [C8mim]X (X = Cl , Br , BF4 , PF6 ) and [Cnmim][BF4] (n = 4, 6, 8). The obtained microstructures of Cu2O were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR). The effects of cations, anions and concentration of the ionic liquids on the morphology of Cu2O were examined in some details. The results suggest that the formation of flowerlike Cu2O was governed by a [C8mim][BF4] controlled reductive reaction mechanism. As one of their applications, the Cu2O nanoparticles were used for the photocatalytic degradation of methylene blue in aqueous solution, and high photocatalytic activity was observed.     

Surfactant assisted hydrothermal synthesis of SnO nanoparticles with enhanced photocatalytic activity

SnO nanoparticles have been successfully synthesized in the presence of Triton-X 100 (TX-100) surfactant via hydrothermal method for the first time, and the photocatalytic activity under UV and visible light irradiation for the degradation of Methylene Blue (MB) and Rhodamine B (RdB) organic textile dyes was investigated. The structural, morphological and chemical characterizations were investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), UV–vis. diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence (PL) analysis. The results reveal that the addition of surfactant, TX-100, in the precursor solutions leads to reduction in crystallite size with significant changes in morphological structure of SnO nanoparticles. The synthesized SnO nanoparticles show excellent photocatalytic activity under UV or visible light irradiation. MB and RdB dyes degraded completely under UV irradiation after 90 and 150 min, respectively. Also, MB and RdB dyes degraded only 150 min later under visible light illumination with a little amount of photocatalyst (0.8 g/L). Hence, this work explores the facile route to synthesizing efficient SnO nanoparticles for degrading organic compound under both UV and visible light irradiations.     

Sustainable fabrication of silver-titania nanocomposites using goji berry (Lycium barbarum L.) fruit extract and their photocatalytic and antibacterial applications

Silver-titania nanocomposites (Ag-TiO₂ NCs) have unique functional attributes due to their photocatalytic and antibacterial properties. In this study, titania nanoparticles (TiO₂-NPs) were successfully in-situ decorated with silver nanoparticles (Ag-NPs) using the aqueous extract of goji berries (Lycium barbarum L.) as a bioreducing and stabilizing agent. Different Ag-TiO₂ NCs were synthesized by treating different concentrations of silver nitrate with a specific concentration of TiO₂-NPs in the presence of fruit extract. The green-synthesized NCs were characterized using several techniques viz., ultraviolet–visible spectrophotometry, X-ray diffractometry (XRD), scanning electron microscopy, field-emission transmission electron microscopy (FE-TEM), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. XRD analysis revealed the formation of face-centered cubic (fcc) crystals, and FE-TEM analysis revealed the embedment of Ag-NPs throughout the surface of TiO₂-NPs. The average size of Ag-NPs on TiO₂-NPs increased from 11.2 ± 3.05 nm to 16.4 ± 4.5 nm with an increase in the concentration of silver ions, and the morphology of Ag-NPs was predominantly quasi-spherical and hexagonal. These NCs exhibited an excellent photocatalytic degradation of an azo dye, methylene blue (MB). The synthesized Ag-TiO₂ NCs (3:1) showed higher photocatalytic degradation efficiency of ∼ 93.4% for MB in 130 min under visible light irradiation. Ag-TiO₂ NC_S also exhibited good antibacterial activities towards Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Therefore, the formation of Ag-NPs on the surface of TiO₂-NPs to form Ag-TiO₂ NCs exhibits eco-friendly photocatalytic degradation of azo dye contaminants as well as antibacterial activity.     

Magnetic ZnO Crystal Nanoparticle Growth on Reduced Graphene Oxide for Enhanced Photocatalytic Performance under Visible Light Irradiation

Magnetite zinc oxide (MZ) (Fe₃O₄/ZnO) with different ratios of reduced graphene oxide (rGO) was synthesized using the solid-state method. The structural and optical properties of the nanocomposites were analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis/DRS), and photoluminescence (PL) spectrophotometry. In particular, the analyses show higher photocatalytic movement for crystalline nanocomposite (MZG) than MZ and ZnO nanoparticles. The photocatalytic degradation of methylene blue (MB) with crystalline ZnO for 1.5 h under visible light was 12%. By contrast, the photocatalytic activity for MZG was more than 98.5%. The superior photocatalytic activity of the crystalline nanocomposite was detected to be due to the synergistic effect between magnetite and zinc oxide in the presence of reduced graphene oxide. Moreover, the fabricated nanocomposite had high electron–hole stability. The crystalline nanocomposite was stable when the material was used several times.     

Fe-CuS/还原氧化石墨烯(RGO)的制备及其光催化性能

以氯化铜（CuCl₂·2H₂O）、硫脲（（NH₂）₂CS,Tu）、1,2-丙二醇（1,2-PG）、氯化铁（FeCl₃·6H₂O）及氧化石墨烯（GO）为原料,通过溶剂热法制备了具有可见光活性的Fe-CuS/RGO复合材料。采用XRD、SEM、TEM、Raman、XPS、TG、UV-Vis等手段对产品进行了表征,并以亚甲基蓝（MB）为目标降解物对其可见光催化活性进行了研究。光催化结果表明：在汞灯（150 W）下照射140 min,CuS、CuS/RGO和Fe-CuS/RGO对MB的脱色率分别为41.2%、81.5%和90.6%。Fe-CuS/RGO对MB的降解效率较CuS/RGO和CuS有较大提升,可能原因是Fe元素有利于电荷在CuS与RGO界面间传输,降低了光生电子-空穴对的复合几率,进而提高了光催化活性。     

Fe-CuS/还原氧化石墨烯(RGO)的制备及其光催化性能

以氯化铜(CuCl_2·2H_2O)、硫脲((NH2)2CS,Tu)、1,2-丙二醇(1,2-PG)、氯化铁(FeCl_3·6H_2O)及氧化石墨烯(GO)为原料,通过溶剂热法制备了具有可见光活性的Fe-CuS/RGO复合材料。采用XRD、SEM、TEM、Raman、XPS、TG、UV-Vis等手段对产品进行了表征,并以亚甲基蓝(MB)为目标降解物对其可见光催化活性进行了研究。光催化结果表明:在汞灯(150 W)下照射140 min,CuS、CuS/RGO和Fe-CuS/RGO对MB的脱色率分别为41.2%、81.5%和90.6%。Fe-CuS/RGO对MB的降解效率较CuS/RGO和CuS有较大提升,可能原因是Fe元素有利于电荷在CuS与RGO界面间传输,降低了光生电子-空穴对的复合几率,进而提高了光催化活性。     

Azo dyes degradation using TiO2-Pt/graphene oxide and TiO2-Pt/reduced graphene oxide photocatalysts under UV and natural sunlight irradiation

The photocatalytic degradation of azo dyes with different structures (amaranth, sunset yellow and tartrazine) using TiO₂-Pt nanoparticles (TPt), TiO₂-Pt/graphene oxide (TPt-GO) and TiO₂-Pt/reduced graphene oxide (TPt-rGO) composites were investigated in the presence of UV and natural sunlight irradiation. The composites were prepared by a combined chemical-thermal method and characterized by Transmission Electron Microscopy (TEM), X-ray powder diffraction (XRD), Infrared (FTIR) and UV–Vis spectroscopy. The modification of TiO₂-Pt with graphene oxide shifted its optical absorption edge towards the visible region and increased its photocatalytic activity under UV and natural sunlight irradiation. The efficiency of catalysts on azo dyes degradation (in similar conditions) reached high values (above 99%) under sunlight conditions, proving the remarkable photocatalytic activities of obtained composites. TPt-GO nanocomposite exhibited higher photoactivity than TPt or TPt-rGO, demonstrating degradation efficiencies of 99.56% for amaranth, 99.15% for sunset yellow and 96.23% for tartrazine. The dye photodegradation process follows a pseudo-first-order kinetic with respect to the Langmuir-Hinshelwood reaction mechanism. A direct dependence between azo dyes degradation rate and chemical structure of dyes has been observed.     

An experimental and theoretical study on the structure and photoactivity of XFe2O4 (X = Mn,Fe, Ni,Co, and Zn) structures

XFe₂O₄ magnetic nanoparticles (X = Mn, Fe, Co, Ni, and Zn) were prepared by using two methods: coprecipitation and hydrothermal. The synthesized nanoparticles were compared according to the separation in an external magnetic field and finally, the hydrothermal method was specified as a better synthesis method. The magnetic nanoparticles were characterized by physico-chemical analysis methods such as Vibrating Sample Magnetometer (VSM), X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), nitrogen adsorption-adsorption isotherm and Transmission Electron Microscopy (TEM). Magnetic properties of synthesized nanoparticles were studied by ab-initio theoretical methods to confirm and compare with the experimental results. According to the VSM analysis, all of magnetic nanoparticles had good magnetization while CoFe₂O₄ nanoparticles showed the ferromagnetic behavior. The magnetic properties of XFe₂O₄ configurations were studied using Density Functional Theory ab-initio method. The theoretical results were consistent with experimental magnetizations in the absence of external field. Finally, the photocatalytic behavior of prepared samples was investigated in the presence of oxone as an accelerated agent for degradation of an azo dye.     

Synthesis,characterization, X-ray structure,electrochemistry, photocatalytic activity and DFT studies of heterotrinuclear Ni(II), Pd(II) and Zn(II) complexes containing a formylferrocene thiosemicarbazone ligand

Three complexes of the general formula M{CpFe(η⁵-C₅H₄CH=N–N=C(S)NH₂}₂ [where M = Ni^II ( 2a ), Pd^II ( 2b ) and Zn^II ( 2c )] were synthesized with formylferrocene thiosemicarbazone ( 1 ) as a bidentate ligand. All compounds were characterized using conventional spectroscopic and analytical techniques (infrared, ¹H and ¹³C NMR, mass spectrometry and elemental analysis). The molecular structure of 2b was confirmed by single-crystal X-ray analysis. To study the photocatalytic activity of the new complexes ( 2a–c ), methylene blue (MB) was selected as a model pollutant. After 180 min, the degradation efficiency of MB reached 87% for 2a , 76% for 2b and 85% for 2c , and all complexes showed a higher photocatalytic activity than the formylferrocene thiosemicarbazone free ligand 1 . Theoretical studies were used to characterize the geometry and electronic structure of the compounds and to provide a rational explanation for the measured photocatalytic activity.     

Ag3PO4/MoS2纳米片复合催化剂制备及可见光催化性能

采用机械球磨法成功制备Ag₃PO₄/MoS₂纳米片复合催化剂。运用X射线衍射仪（XRD）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）、紫外可见漫反射光谱（UV-Vis）和荧光发射光谱（PL）对复合催化剂的结构和形貌进行了表征。结果表明,Ag₃PO₄纳米粒子均匀地附着在MoS₂纳米片层结构上,两者形成紧密结合。以亚甲基蓝为模拟污染物,研究复合催化剂在可见光照射下的光催化特性;通过循环实验考察复合催化剂的稳定性。结果显示,含有1%的MoS₂纳米片与Ag₃PO₄形成的复合催化剂在30 min内对亚甲基蓝的降解率为95%,其降解动力学常数是纯相Ag₃PO₄的2倍。经过5次循环实验后复合催化剂对于亚甲基蓝的降解率为84%,而纯Ag₃PO₄对于亚甲基蓝的降解率仅为35%。Ag₃PO₄/MoS₂纳米片复合催化剂具有优良的光催化活性和高稳定性,主要归因于二硫化钼纳米片与磷酸银形成异质结,磷酸银激发的电子和二硫化钼纳米片产生的空穴直接复合,从而促使光生电子从磷酸银晶体表面快速分离,减轻了磷酸银的光电子腐蚀,同时也提高了复合物的光催化活性。     

Synthesis and Characterization of CeO2 Nanoparticles via Solution Combustion Method for Photocatalytic and Antibacterial Activity Studies

CeO₂ nanoparticles have been proven to be competent photocatalysts for environmental applications because of their strong redox ability, nontoxicity, long-term stability, and low cost. We have synthesized CeO₂ nanoparticles via solution combustion method using ceric ammonium nitrate as an oxidizer and ethylenediaminetetraacetic acid (EDTA) as fuel at 450 °C. These nanoparticles exhibit good photocatalytic degradation and antibacterial activity. The obtained product was characterized by various techniques. X-ray diffraction data confirms a cerianite structure: a cubic phase CeO₂ having crystallite size of 35 nm. The infrared spectrum shows a strong band below 700 cm⁻¹ due to the Ce−O−Ce stretching vibrations. The UV/Vis spectrum shows maximum absorption at 302 nm. The photoluminescence spectrum shows characteristic peaks of CeO₂ nanoparticles. Scanning electron microscopy (SEM) images clearly show the presence of a porous network with a lot of voids. From transmission electron microscopy (TEM) images, it is clear that the particles are almost spherical, and the average size of the nanoparticles is found to be 42 nm. CeO₂ nanoparticles exhibit photocatalytic activity against trypan blue at pH 10 in UV light, and the reaction follows pseudo first-order kinetics. Finally, CeO₂ nanoparticles also reduce Cr^VI to Cr^III and show antibacterial activity against Pseudomonas aeruginosa.