Photocatalyst For Degradation Research Articles

Characterization of NiOAg thin film applicated as photocatalyst for degradation of methylene blue dye waste in Yogyakarta textile factory

Thin films of NiOAg were grown onto glass substrates by radio frequency (RF) sputtering technique at 13.56 MHz RF with variation in oxygen pressure. The research was conducted on preparation and characterization of NiOAg thin films, applicated as a photocatalyst for the degradation of methylene blue. X-ray diffraction analysis showed stronger intensity (111) and (200) planes at peak 2θ of 37.66° and 43.23°. Energy dispersive x-ray analysis showed the following composition: Ni = 40.45%, Ag = 13.01%, and O = 46.53%. Based on UV–vis, it was found that the bandgap energy was 2.8, 3.1, and 3.2 eV for oxygen pressures of 0.05, 0.1, and 0.15 × 10−2 mbar, respectively. From the experiment on the degradation of methylene blue, which was taken from textile factory dye waste in Yogyakarta/Indonesia, the best value of degradation was obtained as 91.96%.

CuBi2O4/Bi2MoO6 heterojunction photocatalyst for degradation of tetracycline and rhodamine B: preparation, characterization, and mechanism study

CuBi2O4/Bi2MoO6 heterojunction photocatalyst for degradation of tetracycline and rhodamine B: preparation, characterization, and mechanism study

Rational Design and Synthesis of Fe-Doped Co-Based Coordination Polymer Composite Photocatalysts for the Degradation of Norfloxacin and Ciprofloxacin.

The solar light-responsive Fe-doped Co-based coordination polymer (Fe@Co-CP) photocatalyst was synthesized under mild conditions. [Co(4-padpe)(1,3-BDC)]n (Co-CP) was first constructed using mixed ligands through the hydrothermal method. Then, Fe was introduced into the Co-CP framework to achieve the enhanced photocatalytic activity. The optimal Fe@Co-CP-2 exhibited excellent catalytic degradation performance for norfloxacin and ciprofloxacin under sunlight irradiation without auxiliary oxidants, and the degradation rates were 91.25 and 92.66% in 120 min. These excellent photocatalytic properties were ascribed to the generation of the Fe-O bond, which not only enhanced the light absorption intensity but also accelerated the separation efficiency of electrons and holes, and hence significantly improved the photocatalytic property of the composites. Meanwhile, Fe@Co-CP-2 displayed excellent stability and reusability. In addition, the degradation pathways and intermediates of antibiotic molecules were effectively analyzed. The free radical scavenging experiment and ESR results confirmed that •OH, •O2-, and h+ active species were involved in the catalytic degradation reaction; the corresponding mechanisms were deeply investigated. This study provides a fresh approach for constructing Fe-doped Co-CP-based composite materials as photocatalysts for degradation of antibiotic contaminants.

Sustainable green synthesis of SnO2 quantum dots: A stable, phase-pure and highly efficient photocatalyst for degradation of toxic dyes

A facile, scalable, green, convenient, high yield and environmentally sustainable strategy has been devised to synthesize SnO2 quantum dots as fine amorphous powder using an aqueous extract of edible and abundantly available marine alga, Ulva sp. The phytochemicals present in the alga have served as capping and stabilizing agent in the synthesis. The structure, morphology, optical properties and chemical oxidation state of the materials were investigated by UV–Vis, FT-IR, Raman, XRD, XPS, TEM, SEM, EDAX and BET techniques. The size of as-synthesized SnO2 nanoparticles were <5 nm indicating the formation of quantum dots (QDs). Retrievable and reusable, the as prepared SnO2 QDs served as highly efficient photocatalyst for fast degradation of water soluble toxic dyes viz., methylene blue (MB), methyl orange (MO) and rhodamine B (RhB) individually, also their binary mixtures, MB-MO, MB-RhB and ternary mixtures MB-MO-RhB under naturally available scattered sunlight. A significant reduction in total organic carbon (TOC) by the SnO2 QDs catalyst suggests that it efficiently converted MB, MO, and RhB dyes into less harmful intermediate products or directly into CO2 and H2O, making them environmentally benign. The catalytic performances of the newly prepared material were assessed to be much higher than several reported SnO2 or metal doped SnO2 nanomaterials. The as-synthesized SnO2 QDs photocatalyst could be recovered reused for at least five consecutive catalytic cycles without any decline in efficiency indicating the high stability of the photocatalyst.

Surface Modification of p‐type ZnO Nanorods by Nitrogen Doped SiO2 Dots as an Efficient Solar Photocatalyst for Degradation of Ciprofloxacin in Water

AbstractA simple two step hydrothermal method is developed for synthesizing p‐type zinc oxide (ZnO) nanorods surface modified with nitrogen doped silicon dioxide dots (ZnO/N‐SiO2). The structure, morphology, and chemical compositions are confirmed by X‐ray diffraction, Raman spectroscopy, Fourier transformed infrared spectroscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy, and by Mott‐Schottky studies. The N‐SiO2 dots on the surface of p‐type ZnO nanorods are formed during hydrothermal treatment at 90 °C (i.e., at 363 K), named as [ZnO/N‐SiO2]363K. While N‐SiO2 dots are embedded in the ZnO nanorods of the batch synthesized at 453 K. The band gap of the batches of ZnO/N‐SiO2 are wider (3.24–3.30 eV) than the pristine ZnO (3.16 eV). The modification of ZnO nanorods by the N‐SiO2 dots is corroborated by changes in the flat band potential, revealed from Mott‐Schottky measurements. The EPR and photoluminescence studies confirm p‐type ZnO attributable to zinc vacancies (VZn). The batch [ZnO/N‐SiO2]363 exhibits maximum photocatalytic degradation of ciprofloxacin in water. The specific rate constant is k′ = 0.97 min−1 g−1, which is nearly three times higher than that exhibited by the irregularly spherical pristine ZnO nanoparticles (k′ = 0.36 min−1 g−1). The enhanced photocatalytic degradation is attributed to holes mediated hydroxyl radical generation. The degradation mechanism is proposed by carrier mobility studies, radical scavenging studies and by identifying the degradation products.

Preparation of colored TiO2 flower/Ti3C2 for efficient photocatalytic degradation of tetracycline

Herein, colored TiO2 flowers grown on Ti3C2 (XTFT, where X = 250 °C, 300 °C, and 350 °C representing heating temperature) are prepared as photocatalysts for degradation of tetracycline using hydrothermal method and CVD process. TiO2 has a suitable bandgap as a photocatalyst. However, in practical applications, TiO2 cannot effectively utilize visible light and the recombination of photogenerated carriers is excessively fast. The fabrication of XTFT through defect engineering compensates for the shortcomings of pure TiO2 in photocatalytic applications, following which the bandgap of TiO2 is reduced and the TiO2 surface becomes discolored and effectively responds to visible light. Ti3C2, a promising auxiliary material in the field of photocatalysis, is used as a photocatalyst in the degradation of tetracycline via defect engineering. After forming a composite with TiO2, Ti3C2 can effectively separate TiO2 photogenerated carriers to enhance the photocatalytic performance of TiO2. The degradation rate of 50 mL 50 mg/L tetracycline by 50 mg 300TFT under visible light irradiation for 30 min is 96.3 %. Compared with pure TiO2, the photocatalytic efficiency is significantly improved, thus providing a new idea for realization of highly efficient visible photocatalysis in the field of environmental pollution in future.

Photocatalytic degradation of naproxen using TiO2 single nanotubes

Herein, TiO2 single-tube (TiO2 ST-NT) powders with and without magnetite Fe3O4 nanoparticles (TiO2 ST-NT@Fe3O4NPs) are presented for the first time as excellent photocatalysts for the degradation of one of the most popular non-steroidal anti-inflammatory drugs (NSAIDs), naproxen (NPX). The TiO2 ST-NT powders were synthesized by anodization followed by etching of the double wall, bending, sonication, ultra-centrifugation, and finally annealing at 600°C. A part of the obtained TiO2 ST-NT powders was decorated with Fe3O4 nanoparticles using a simple one-step decoration process. The best photocatalytic performance of TiO2 ST-NT and TiO2 ST-NT@Fe3O4NPs powders was obtained under the white light (6.2 × 10−4 s-1) and the blue light (2.7 × 10−4 s-1), respectively. During NPX photodegradation using TiO2 ST-NT powders, three main NPX transformation products (P1, P2, and P3) were detected. Upon excitation with the blue light illumination, TiO2 ST-NT@ Fe3O4NPs powders exhibited higher performance (∼80%) than TiO2 ST-NT powders (∼23%) within 1 h, resulting in an approximately three times increased photocatalytic rate constant. Moreover, under simulated sunlight conditions, TiO2 ST-NT powders demonstrated remarkable activity, achieving a 94% NPX degradation within 1 h. TiO2 ST-NT and TiO2 ST-NT@Fe3O4NPs powders represent excellent photocatalysts for NPX degradation.

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.

Polyaniline grafted Fe3O4@ZnO/GO as a recyclable photocatalyst

A novel superparamagnetic Fe3O4@ZnO/GO (F@Z/G) nanocomposites with different ratios: (1/1, 1/2, 1/3 wt%) of Fe3O4@ZnO core–shell to GO were synthesized using the hydrothermal method. XRD and TEM images indicated the formation of magnetite Fe3O4 and ZnO in the form of core–shell,which were uniformly loaded on GO sheets. In the next step, OH and COOH functional groups of F@Z and GO in F@Z/G nanocomposites used as initiators for in situ polymerization of aniline and polyaniline grafted F@Z/G nanocomposites were named as (F@Z/G1-P, F@Z/G2-P, F@Z/G3-P) were successfully produced. The Formation of polyaniline on F@Z/G nanocomposite was confirmed using FTIR, and XRD. The presence of polyaniline in F@Z/G nanocomposites not only retained their superparamagnetic property of F@Z/G nanocomposites as recyclable photocatalysts for degradation of methylene blue but also increased their degradation efficiency by speeding up the electron-hole production. The Maximum removal efficiency under the same conditions was obtained for F@Z/G2-P nanocomposite which reached 96.10 % during 40 min.

Photocatalytic Degradation of Organic Pollutants-Nile Blue, Methylene Blue, and Bentazon Herbicide-Using NiO-ZnO Nanocomposite.

Water pollution poses a significant threat to both human health and ecosystem integrity. Chemical pollutants such as dyes and pesticides affect the water quality and endanger aquatic life. Among the methods for water purification from organic pollutants, photodegradation is certainly a valid technique to decrease such contaminants. In this work, pristine NiO, ZnO, and NiO-ZnO photocatalysts were synthesized by the homogeneous co-precipitation method. X-ray diffraction confirms the formation of a photocatalyst consisting of ZnO (Hexagonal) and NiO (Cubic) structures. The crystalline size was calculated by the Scherrer formula, which is 19 nm for the NiO-ZnO photocatalyst. The band gap measurements of the prepared samples were obtained using the Tauc Plot, equation which is 2.93 eV, 3.35 eV and 2.63 eV for NiO, ZnO, and NiO-ZnO photocatalysts, respectively. The photocatalytic performance of NiO-ZnO nanocomposite was evaluated through the degradation of Methylene Blue and Nile Blue dyes under sunlight, and Bentazon herbicide under a UV light. Photocatalyst degradation efficiency was 95% and 97% for Methylene Blue and Nile Blue in 220 min under sunlight while a degradation of 70% for Bentazon after 100 min under UV light source was found.

Photochemical modification of tea waste by tungsten oxide nanoparticle as a novel, low-cost and green photocatalyst for degradation of dye pollutant

So far, many adsorbents and nanocomposites have been synthesized by different methods and used to remove or degradation of dye pollutants. Nowadays, the use of natural adsorbents and their modification with simple methods based on metal oxides are of interest to many researchers. In this study, for the first time, we report the simple and low-cost modification of tea pomace waste (TPW) with tungsten oxide (WO3) based on the photochemical method as a green, cost-effective, and biodegradable photocatalyst for the degradation of Rh B dye pollutant. The results obtained from FE-SEM, EDAX, XRD, XPS, PL, BET and UV–Vis Diffusive Reflectance (DRS) analyses confirmed the successful modification of the TPW surface with WO3 (WO3/TPW). The parameters affecting the photocatalytic behavior of WO3/TPW, including the time of photochemical modification and the type of radiation on its photocatalytic activity, were carefully optimized. WO3/TPW showed excellent photocatalytic activity compared to TPW for the degradation of Rh B dye pollutant under UV light for 30 min (94 %). Finally, the effective parameters on the value of Rh B dye degradation by WO3/TPW photocatalyst including pH, adsorbent dosage, the concentration of dye pollutant, and the kinetics of the degradation process were studied. It is expected that this type of photochemical modification method and natural WO3/TPW photocatalyst will be a promising path for the synthesis, modification, and increase of the photocatalytic performance of natural adsorbents.

Hydrothermal-assisted synthesis of Sr-doped SnS nanoflower catalysts for photodegradation of metronidazole antibiotic pollutant in wastewater promoted by natural sunlight irradiation.

In this study, we report a facile hydrothermal synthesis of strontium-doped SnS nanoflowers that were used as a catalyst for the degradation of antibiotic molecules in water. The prepared sample was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible absorption spectroscopy (UV-Vis). The photocatalytic ability of the strontium-doped SnS nanoflowers was evaluated by studying the degradation of metronidazole in an aqueous solution under photocatalytic conditions. The degradation study was conducted for a reaction period of 300 min at neutral pH, and it was found that the degradation of metronidazole reached 91%, indicating the excellent photocatalytic performance of the catalyst. The influence of experimental parameters such as catalyst dosage, initial metronidazole concentration, initial reaction pH, and light source nature was optimized with respect to metronidazole degradation over time. The reusability of the strontium-doped SnS nanoflowers catalyst was investigated, and its photocatalytic efficiency remained unchanged even after four cycles of use.

Experimental and first-principle insight into Structural, optical and electrical properties and photocatalytic water purification application of Zn1-xMgxO

Environmental concern essentially demands solemn consideration of industrial waste-water containing organic dyes. To develop efficient photocatalysts for degradation of organic dyes in waste water, metal-oxide nanostructures are the promising candidate owing to their tunable physical properties. The present work emphasizes on the experimental and first-principle (DFT + U) studies to understand the impact of magnesium doping on the structural, optical and electrical properties, and photocatalytic degradation tendency of zinc oxide (ZnO) nano-ceramics. The ZnO lattice contraction endorsed by Mg-doping, has been examined mutually from the first principle calculations and Rietveld refinement investigations. The decrease in crystallite-size (93 to 88 nm) and enrichment in structural imperfections of Zn1-xMgxO nanostructures were analyzed with Williamson-Hall peak profile methods. The band gap broadening of ZnO with Mg doping was demonstrated by UV–visible spectroscopy (3.32 to 3.43 eV) which was further confirmed from DFT + U (3.39 to 3.55 eV) calculations. The increase in dielectric constant and reduction in ac conductivity has been observed due to Mg addition. The photocatalytic performance of Zn1-xMgxO nanostructures was evaluated under sunlight for Methylene-blue (MB) and Congo-red (CR) dyes. The performance has been optimally improved with 6 mol% Mg content leading to degradation of 86.2 % and 58.3 % of MB and CR dyes respectively in 160 min.

Recycling of natural and waste materials as supports for green silver nanoparticles as efficient catalysts in photodegradation of organic pollutants

The use of a sustainable technology to synthesize green silver nanoparticles (AgNP) from renewable resources is very appealing. Here, a green protocol for the production AgNP/composites is introduced, via in situ reduction of Ag+ ions on sustainable materials (clays and waste materials) using eucalyptus leaves extract (ELE) as a reducing and stabilizing agent, without the addition of any harmful or expensive organic solvent, surfactant or dangerous compounds. The synthesized AgNP/composites were evaluated as photocatalysts to degrade Indigo Carmine (IC) dye as a model pollutant under visible light. Kaolin and pistachio shells showed to be promising supports for green AgNP, with decolorization efficiency of 85.3(±1.8)% and 48.3(±4.1)%, respectively, after 120 min of irradiation. The best catalytic results were obtained with kaolin as support and so the influence of different synthesis parameters of AgNP/kaolin nanocomposite was evaluated. The catalytic results indicated that increasing the amount of AgNO3 and ELE in the nanocomposites, increased their photocatalytic performance. Nanocomposites synthesized at room temperature showed smaller amount of AgNP and higher decolorization efficiency, compared to those biosynthesized at 50 °C. The evaluation of active species responsible for the photodegradation of IC showed that O2•- and H+ radicals are species involved in the reaction. The AgNP/kaolin showed also to be efficient to degrade both atrazine and sulfamethoxazole after 120 min of irradiation.

Ag/α-Fe2O3/g-C3N4 nanocomposites as Z-scheme heterojunction photocatalysts for degradation of RhB

In this study, Ag/α-Fe2O3/g-C3N4 composites with varying α-Fe2O3 and Ag contents were synthesized by loading α-Fe2O3 and Ag nanoparticles onto the g-C3N4 with a high specific surface area via acid annealing. These composites were then utilized for the photocatalytic degradation of RhB under the irradiation of visible light. For α-Fe2O3/g-C3N4 composites with 5 wt% content of α-Fe2O3, the degradation efficiency reached a peak of 97.57% within 55 min, which was much higher than that of α-Fe2O3 and acid-annealed g-C3N4 with 45.92% and 83.61%, respectively. Furthermore, the photocatalytic degradation efficiency of Ag/α-Fe2O3/g-C3N4 composites reached its maximum of 99.61% with 1% content of Ag. It was demonstrated that the ternary Z-scheme heterojunction construction leaded to a significant enhancement of carrier separation and transfer effects, while the incorporation of Ag serves as electron reservoirs and photoinduced electrons capturers, thereby significantly enhancing the Fenton reaction and photocatalytic performance. This work is significant to drive the widespread application of g-C3N4 based heterojunctions in photocatalytic water purification.

Significance of synthesized digenite phase of copper sulfide nanoparticles as a photocatalyst for degradation of bromophenol blue from contaminated water

Organic pollutants such as phenolic compounds have received global interest since they are harmful, toxic, and carcinogenic. This work aimed to synthesize copper sulfide nanoparticles in digenite phase (Cu1.8S) via sol–gel method and apply it as a photocatalyst to remove a phenolic contaminate, bromophenol blue (BPB) dye, from water. The copper sulfide nanoparticles were prepared by the sol–gel technique under different conditions, such as reaction temperature, reactant concentration, and aging time, in the presence of a stabilizing agent (cetyltrimethylammonium bromide, CTAB). The synthesized nanoparticles were then described using different characterization techniques. Then these nanoparticles were applied as a photocatalyst for the degradation of bromophenol blue (BPB) under different conditions, including photo-irradiation time, catalyst dosage, dye concentration and power lamp. The aimed copper sulfide digenite nanoparticles (Cu1.8S) were obtained at a 3 h aging time, exhibiting a cubic crystal structure and a size of 8 nm in a 3-dimensional closed-packed structure model with an energy band gap of 1.82 eV. This material has the ability to absorb visible light and thus can be a superior candidate for photocatalysis, demonstrating strong photocatalytic activity towards the degradation of the phenolic dye (i.e., BPB). Excellent results were achieved at a contact time of 3 h, 7 ppm of BPB, 50 mg catalyst dose, and 32 W power lamp. As a consequence, about 96.7% of the contaminants were removed. The photocatalytic degradation was found to obey the Langmuir postulate and exhibit pseudo first order kinetics.

Highly Efficient Photocatalytic H2O2 Production over a Zn0.3Cd0.7S/MXene Photocatalyst for Degradation of Emerging Pollutants under Visible-Light Irradiation.

Hydrogen peroxide (H2O2) is an ideal green product with a broad range of applications, and visible-light-driven photocatalytic H2O2 production is deemed a sustainable and eco-friendly strategy. Herein, various ZnxCd1-xS/MXene photocatalysts with a Schottky junction were prepared for photocatalytic H2O2 production. The obtained Zn0.3Cd0.7S/MXene (ZCM-0.3) hybrid presented the highest photocatalytic H2O2 production rate in pure neutral water of 1160 μmol h-1 g-1, which was further improved to 2178.58 μmol h-1 g-1 in the presence of isopropanol as the sacrificial reagent. The experimental results demonstrated that the sufficient visible-light-harvesting ability and appropriate conduction band potential of the Zn0.3Cd0.7S solid solution, the excellent conductivity and two-electron selectivity of MXene, and the construction of Schottky junctions at the Zn0.3Cd0.7S/MXene interface resulted in the fast transfer and separation of the photogenerated charge carriers and the targeted reduction of oxygen to H2O2. The photocatalytic mechanism for H2O2 production was studied and proposed. Moreover, a simple photo-Fenton system consisting of ZnxCd1-xS/MXene and ferrous ions (Fe2+) was constructed and applied for the degradation of various emerging pollutants, which also performed effectively and exhibited universality across different pollutants. Overall, this study presents a novel and useful strategy to convert solar energy into chemical energy through efficient H2O2 production and provides an effective alternative for the degradation of emerging pollutants.

Pt/MWCNT/ZnTiO3 nanocomposite: An efficient, reusable visible-light responsive photocatalyst for degradation of Thiamethoxam insecticide and methylene blue in aqueous phase

Surface modification and bandgap manipulation of ZnTiO3 are proposed to significantly enhance its photocatalytic activity by reducing charge carrier recombination. In this study, we developed a novel ternary photocatalyst by incorporating Pt nanoparticles (Pt NPs), multiwall carbon nanotubes (MWCNT) and ZnTiO3 nanostructures. The synthesis of ZnTiO3 was carried out using the sol-gel methodology, while the Pt@MWCNT/ZnTiO3 photocatalyst was fabricated through ultrasonication and photo-reduction routes. X-ray diffraction (XRD) analysis confirmed the formation of rhombohedral ZnTiO3, and transmission electron microscopy (TEM) examination revealed a well-dispersed arrangement of Pt NPs on the MWCNT/ZnTiO3 nanocomposite. The successful development of the Pt@MWCNT/ZnTiO3 photocatalyst was affirmed through Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS) examinations. A reduction in the bandgap energy was observed with the modification of ZnTiO3 to the ternary Pt@MWCNT/ZnTiO3. The newly developed Pt@MWCNT/ZnTiO3 photocatalyst demonstrated exceptional effectiveness, achieving a remarkable 92.62 % removal of the insecticide derivative thiamethoxam (TXM) in just 40 min under visible light. This represents 2.12 times greater efficiency than pure ZnTiO3. Moreover, the Pt@MWCNT/ZnTiO3 nanostructure exhibited remarkable efficacy in the degradation of methylene blue (MB) dye, eliminating its complex structure in just 12 min, with excellent reusability. The outstanding photodegradation capabilities of Pt@MWCNT/ZnTiO3 can be attributed to the presence of highly ordered mesoporous ZnTiO3, an increase in surface area, a favorable bandgap, and improved visible light absorption. Additionally, this Pt@MWCNT/ZnTiO3 photocatalyst demonstrated effective mitigation of charge carrier recombination. The highly efficient nature of the developed ternary Pt@MWCNT/ZnTiO3 photocatalyst holds substantial promise for widespread applications in environmental remediation activities.

Efficient synergistic degradation of Congo red and omeprazole in wastewater using rGO/Ag@ZnO nanocomposite

Photocatalytic degradation is an effective and eco-friendly technique that can address environmental pollution, especially water pollution. We prepared rGO-decorated with silver-doped zinc oxide (rGO/Ag@ZnO) nanocomposite as the efficient photocatalyst for Congo red and Omeprazole degradation. The nanocomposite was characterized using advanced spectroscopic and imaging techniques. The low band gap of 2.05 eV enables rGO/Ag@ZnO nanocomposites to be an efficient photocatalyst for the degradation of multiple pollutants. The BET analysis revealed that the rGO/Ag@ZnO nanocomposite possesses a substantial surface area of 51 m2/g, indicative of enhanced porosity, while the estimated surface area for Ag@ZnO is approximately 18.56 m2/g, reflecting the significant contribution of rGO to the composite's adsorptive properties. The rGO/Ag@ZnO nanocomposites showed an excellent 93.77 % degradation of Congo red in 40 min and 95.6 % degradation of Omeprazole in 30 min under the optimized conditions. The photocatalyst rGO/Ag@ZnO retains its efficiency over five cycles, providing a cost-effective, eco-friendly solution for continuous water pollutant treatment. The exceptional degradation efficiency of rGO/Ag@ZnO was achieved through optimization of the photocatalytic process while previously reported materials exhibit longer degradation times with lower degradation percentages (80–90 %). These excellent photocatalytic properties highlight rGO/Ag@ZnO as an effective and rapid solution to address the water pollution caused by different environmental contaminants. The results support the practical use of rGO/Ag@ZnO in real-world water treatment systems contributing to a healthier environment.

A facile synthetic approach for TiO2@NiO core‐shell nanoparticles using TiO2@Ni(OH)2 precursors and their photocatalytic application

AbstractThe current study presents a simple and an efficient chemical method for the synthesis of TiO2@NiO core‐shell nanoparticles (CSNPs) as photocatalyst for effective degradation of rhodamine B (RhB) in an aqueous solution upon sunlight irradiation. First, TiO2 spheres were synthesized using a wet chemical method. Then, TiO2@Ni(OH)2 precursors were prepared via homogeneous precipitation and TiO2@NiO core‐shell nanoparticles were obtained on calcination of the precursors. The synthesized precursors and the TiO2@NiO CSNPs were analyzed using XRD, FT‐IR, FESEM and DRS. XRD data shows the presence of both TiO2 and NiO phases in the TiO2@NiO samples. FE‐SEM and TEM analyses confirm coating of NiO NPs on TiO2 spheres with varying shell thickness (40 nm to 170 nm). Optical studies reveal that TiO2@NiO CSNPs possess band gap of about 3.7 eV. Photoluminescence (PL) results show lower recombination rate of e− and h+ pairs in the TiO2@NiO CSNPs. XPS studies confirm the presence of different elements in the TiO2@NiO CSNPs. Magnetic investigations reveal ferromagnetic behavior of the core‐shell NPs at 5 K. The TiO2@NiO CSNPs were explored as photocatalyst for the degradation of rhodamine B in water under natural sunlight. The TiO2@NiO CSNPs exhibit better photocatalytic activity compared to TiO2 and NiO nanoparticles.