Decoration Of Nanoparticles Research Articles

Gas Sensing Properties of PLD Grown 2D SnS Film: Effect of Film Thickness, Metal Nanoparticle Decoration, and In Situ KPFM Investigation.

This study employs novel growth methodologies and surface sensitization with metal nanoparticles to enhance and manipulate gas sensing behavior of two-dimensional (2D)SnS film. Growth of SnS films is optimized by varying substrate temperature and laser pulses during pulsed laser deposition (PLD). Thereafter, palladium (Pd), gold (Au), and silver (Ag) nanoparticles are decorated on as-grown film using gas-phase synthesis techniques. X-ray diffraction (XRD), Raman spectroscopy, and Field-emission scanning electron microscopy (FESEM) elucidate the growth evolution of SnS and the effect of nanoparticle decoration. X-ray photoelectron spectroscopy (XPS) analyses the chemical state and composition. Pristine SnS, Ag, and Au decorated SnS films are sensitive and selective toward NO2 at room temperature (RT). Ag nanoparticle increases the response of pristine SnS from 48 to 138% toward 2ppm NO2, which indicates electronic and chemical sensitization effect of Ag. Pd decoration on SnS tunes its selectivity toward H2 gas with a response of 55% toward 70ppm H2 and limit of detection (LOD) < 1ppm. In situ Kelvin probe force microscopy (KPFM) maps the work function changes, revealing catalytic effect of Ag toward NO2 in Ag-decorated SnS and direct charge transfer between Pd and SnS during H2 exposure in Pd-decorated SnS.

Controlled Synthesis of Metal‐Nanoparticles Decorated Block Copolymer Hybrid Particles via Emulsion Confined Self‐assembly and Their Catalytic Applications

Comprehensive SummaryMetal nanoparticles (NPs) decorated block copolymer (BCP) hybrid nanoparticles have attracted enormous attention for their actual value in catalysis, medical therapy, and bioengineering. The confined assembly of BCPs within evaporative emulsion droplet is verified as an effective method to provide polymeric scaffolds to load metal NPs. However, to date, it remains challenging to generate different types of metal NPs decorated BCP hybrid nanoparticles. Herein, we employed the emulsion confined self‐assembly of poly(styrene‐b‐ 2‐vinylpyridine) (PS‐b‐P2VP) and the followed seed‐mediated growth of Au and palladium (Pd) NPs onto well‐defined BCP particles to design a series of Au/Pd decorated BCP hybrid nanoparticles, which exhibited excellent catalytic activity for the reduction of 4‐nitrophenol to 4‐aminophenol with the reductant of NaBH4. This work may inspire more researchers to investigate the selective decoration of different metal NPs onto the polymeric scaffolds, broadening the potential applications of the inorganic/organic hybrid nanoparticles.

Scalable Decoration of Au Nanoparticles onto Al Nanoconcavities Arrays for Highly Enhanced SERS Detection

Highly sensitive Raman signal enhancement of target molecules is achieved by developing effective surface-enhanced Raman spectroscopy (SERS) sensing platforms created by the unique combination of plasmonic gold nanofractals and highly...

γ-Fe2O3 decorating N,S co-doped carbon nanosheets as a cathode electrocatalyst for different-scenario fuel cells

The decoration of γ-Fe2O3 nanoparticles onto N,S co-doped carbon nanosheets enhances their catalytic activity for the oxygen reduction reaction (ORR) in both neutral and alkaline environments, making them a promising candidate for applications in various fuel cell scenarios.

In situ laser-assisted decoration of Au nanoparticles on 3D porous graphene for enhanced 2-CEES sensing

In situ Au decorated laser-induced graphene (LIG/Au) behaves as an effective near-room-temperature 2-chloroethyl ethyl sulfide (2-CEES) sensor. It exhibits an enhanced response of 7.85‰ to 1.0 ppm 2-CEES, which is twice as that of pure LIG.

Regulating thermal diffusion of gold thin films at solid-state interfaces for site-selective decoration of gold nanoparticles on titania nanotubes as an efficient SERS sensing platform

Regulating thermal diffusion and dewetting of Au thin films at the confined ZnO/TiO2 interface favors an optimal distribution of the produced Au nanoparticles for forming localized electromagnetic field hot spots.

Gold Nanoparticles Decoration of Zinc Oxide Nanostructures for Bio-Sensing Applications

ZnO nanowalls (NWLs) is a non-toxic, high surface-to-volume ratio semiconducting nanostructure which has already showed potential applications in biosensing applicationsRecently, it was discovered that decorating the metal oxide nanostructures with noble metal nanoparticles (NP) opens the doors to fabricating biosensors to detect volatile organic compounds. The aim our work is to improve the knowledge and understanding of fabricating ZnO nanowalls decorated with metal nanoparticles.ZnO nanowalls wereas deposited both on rigid on flexible substrates at low temperature using rather simple and low-cost processes.We examined the formation process of ZnO nanowalls on Polyimide substrate and studied the new obtained structure at the nanoscale, at different conditions such as growth temperature, concentration and time. The morphology of the ZnO nanowalls obtained under each of these conditions was studied. The crystal structure of the ZnO nanowalls at different growth temperatures was studied by X-ray diffraction.Next, NP decoration of gold and platinum was conducted. A study of the nucleation and growth of the ZnO nanowalls, and of the NP decoration at different schemes of surface functionalization, was conducted.The first attempts for NP deposition achieved NP clusters with irregular morphology, however at well-kept conditions we succeeded in achieving a good dispersion of NP (figure 1(b).)The metal nanoparticle surface functionalization poses some material-related questions regarding the behavior of that nano-structured material, when exposed to volatile organic compounds (e.g. Ethylene). This will allow us to develop a novel family of biosensors that enable sensitivity, rapidity, and selectivity for the detection of a wide range of target analytes.The final goal is a flexible all-in-one, highly sensitive and selective biosensors using relatively simple and low cost materials and processing. The sensors will use recent advances in functionalized Gold NP decorated ZnO electrodes based sensors. Figure 1

Intravenous Injection of PEI-Decorated Iron Oxide Nanoparticles Impacts NF-kappaB Protein Expression in Immunologically Stressed Mice.

Nanoparticle-based formulations are considered valuable tools for diagnostic and treatment purposes. The surface decoration of nanoparticles with polyethyleneimine (PEI) is often used to enhance their targeting and functional properties. Here, we aimed at addressing the long-term fate in vivo and the potential "off-target" effects of PEI decorated iron oxide nanoparticles (PEI-MNPs) in individuals with low-grade and persistent systemic inflammation. For this purpose, we synthesized PEI-MNPs (core-shell method, PEI coating under high pressure homogenization). Further on, we induced a low-grade and persistent inflammation in mice through regular subcutaneous injection of pathogen-associated molecular patterns (PAMPs, from zymosan). PEI-MNPs were injected intravenously. Up to 7 weeks thereafter, the blood parameters were determined via automated fluorescence flow cytometry, animals were euthanized, and the organs analyzed for iron contents (atomic absorption spectrometry) and for expression of NF-κB associated proteins (p65, IκBα, p105/50, p100/52, COX-2, Bcl-2, SDS-PAGE and Western blotting). We observed that the PEI-MNPs had a diameter of 136 nm and a zeta-potential 56.9 mV. After injection in mice, the blood parameters were modified and the iron levels were increased in different organs. Moreover, the liver of animals showed an increased protein expression of canonical NF-κB signaling pathway members early after PEI-MNP application, whereas at the later post-observation time, members of the non-canonical signaling pathway were prominent. We conclude that the synergistic effect between PEI-MNPs and the low-grade and persistent inflammatory state is mainly due to the hepatocytes sensing infection (PAMPs), to immune responses resulting from the intracellular metabolism of the uptaken PEI-MNPs, or to hepatocyte and immune cell communications. Therefore, we suggest a careful assessment of the safety and toxicity of PEI-MNP-based carriers for gene therapy, chemotherapy, and other medical applications not only in healthy individuals but also in those suffering from chronic inflammation.

Novel MgO and Ag/MgO nanoparticles green-synthesis for antibacterial and photocatalytic applications: A kinetics-mechanism & recyclability

The present study identifies the novel nano production of MgO nanoparticles as well as the Ag decoration of MgO nanoparticles using Morinda tinctoria plant extract. Green compounds are used to reduce zero valent atoms and to decorate metal oxide surfaces. X-ray Diffractometer analysis (XRD) was used to examine the cubic structure of MgO (28 nm) and Ag/MgO (21 nm) nanoparticles. Fourier transform infrared spectroscopy (FTIR) analysis was used to determine the reactive functional groups, metal–oxygen bonding, and OH molecules. Ultra-Violet Diffuse Reflectance Spectroscopy (UV-DRS) analysis revealed the optical entity and their orbital electron shift. Using the Kubelka-Munk relation, the optical defect of MgO (4.68 eV) and Ag/MgO (3.18 eV) nanoparticles was calculated. Scanning Electron Microscope (SEM) indicated surface decorations and their pure MgO nanoparticles rod-like shape, and Energy-Dispersive X-Ray Spectroscopy (EDX) identified their elements. TEM analysis confirmed the poly-dispersive nature of the Ag decorations on the MgO surface. X-Ray Photoelectron Spectroscopy (XPS) was used to determine the valency of metal (Ag-3d) and metal oxide (Mg-2 s&O-1 s). MgO and Ag/MgO were used in visible light photocatalytic dye degradation of Rh-B dye. The biological properties were tested against S.aureus and E.coli. The plasmonic decoration on the MgO surface accelerated photodegradation and increased biological susceptibility. The innovative characteristics of this work squeeze the green synthesis of Ag/MgO nanoparticles, their improved photocatalytic and antibacterial performance, and their potential applications in water remediation and biomedicine.

Decoration of 0D Bi3NbO7 nanoparticles onto 2D BiOIO3 nanosheets as visible-light responsive S-scheme photocatalyst for photo-oxidation of antibiotics in wastewater

In this work, a new S-type hybrid composed of 2D BiOIO3 and 0D Bi3NbO7 was proposed and hybridized by a facile self-assembly strategy. The developed nanomaterials were characterized and identified by a series of sophisticated analyses, like XRD, SEM, EIS, XPS, PL, UPS, EDS, BET, M-S, TEM, HRTEM, and DRS. The photocatalytic behavior of BiOIO3/Bi3NbO7 was examined and optimized against amoxicillin (AMX) and other types of antibiotics under a variety of environmental conditions, such as visible light (150 W LED), direct sunlight, pH (3–11), catalyst dosages (20–80 mg), humic acid (0–24 mg/L), AMX concentration (10–40 mg/L), and different inorganic ions (0.05 M). The optimized BiOIO3/Bi3NbO7 hybrid attained exceptional AMX degradation activity (96.5%) under visible light (60 min), with a reaction constant of up to 0.04559 min−1, exceeding bare BiOIO3 and Bi3NbO7 by 5.57 and 5.3 folds, respectively. The obtained BiOIO3/Bi3NbO7 hybrid unclosed expanded light utilization behavior compared with neat catalysts, which originates from the powerful incorporation between BiOIO3 and Bi3NbO7 in the S-type system. The radical investigations confirmed the superiority of BiOIO3/Bi3NbO7 in generating both •OH and •O2− during the photoreaction. The novel Bi3NbO7-based heterojunction afforded robust photostability in five treatment cycles and simple charge transfer activity in the S-type route, boosting the photo-mechanism for antibiotic degradation in an efficient manner. The building of the S-scheme heterojunction between BiOIO3 and Bi3NbO7 stimulates the utilization of holes by the recombination process and promotes the overall stability of the composite. Our study introduces a new class of semiconductor heterojunctions that may contribute to the development potential of the photocatalysis sector in wastewater treatment.

Fabrication of large-area Au nanoparticle decorated ZnO@ZIF-8 core-shell heterostructure nanorods for ppb-level NO2 gas sensing at room temperature

Metal-organic frameworks based heterostructures have gained wide attention recently for various applications. Specifically metal oxide and zeolitic imidazolate framework-8 (ZIF-8) nanocomposites have been synthesized for gas sensing with reasonable performance. In this work, large-area Au nanoparticle (NP) decorated ZnO@ZIF-8 core-shell heterostructure nanorods (NRs) are synthesized for ppb-level UV-activated NO2 sensing at room temperature. Large-area ZnO NRs are first grown and ZIF-8 shells are subsequently formed on ZnO with the result of various types of ZnO@ZIF-8 NRs. The ZnO@3ZIF-8 NRs have the highest response and Au NPs are finally decorated on the NR surfaces. The ZnO@3ZIF-8/Au sensor shows high responses of 260% and 34700% toward 0.05 and 3.75 ppm NO2 gas, respectively. An excellent linear sensitivity of 95.1 ppm–1 has been achieved and the estimated lowest detection limit is 0.3 ppb. It is noteworthy that the linear dynamic range is extended by at least 8 times after ZIF-8 addition and the sensitivity is enhanced by 12 times after Au NP decoration. The sensor is also highly NO2 selective against other gases including NO, NH3, SO2, CO, CH3OH, CH2O, C2H5OH, and C3H6O. The excellent performance of the ZnO@3ZIF-8/Au sensor shows good potential for environmental NO2 sensing.

Synergistic effects of Pd-Ag decoration on SnO/SnO2 nanosheets for enhanced hydrogen sensing

Hydrogen, the lightest and most abundant element in the universe, holds immense importance across various fields of application from industry to healthcare. Detecting hydrogen is crucial in medical diagnostics and leak detection, as it helps diagnose gastrointestinal conditions and ensures safety in industrial settings by identifying potential leaks in hydrogen-based systems. In this study, we present the synthesis of tin oxide (SnO/SnO2) nanosheets using a facile hydrothermal method followed by the decoration of Pd-Ag alloy nanoparticles (NPs) for the purpose of hydrogen gas detection. Different combinations of Pd and Ag in Pd-Ag alloy NPs were tested on the surface of the SnO/SnO2 nanosheets in order to optimize their catalytic properties for enhanced hydrogen gas sensing. The Pd-Ag alloy NPs with a ratio of 1:0.5 decorated on SnO/SnO2 nanosheets (Pd1Ag0.50@SnO/SnO2), exhibited the highest response (s = Ra/Rg) of 81.34 at an optimum temperature of 225 °C compared to the bare SnO/SnO2 nanosheets. The fabricated sensor also showed an excellent level of selectivity, repeatability, and a good response time (45 s). The enhanced sensing response of Pd1Ag0.50@SnO/SnO2 towards hydrogen is explained using the spillover and electronic sensitization mechanism. The combined gas sensing mechanism is discussed in detail.

Improved SnO2 nanowire acetone sensor with uniform Co3O4 nanoparticle decoration

In this study, the synthesis of Co3O4 nanoparticles (NPs) decorated onto SnO2 nanowires (NWs) was achieved through a meticulous vapor-liquid-solid (VLS) process coupled with a hydrothermal approach. The paramount objective was to amplify the gas sensing efficacy and refine the detection threshold of the acetone gas sensor. This endeavor encompassed a twofold enhancement strategy: the optimization of Co3O4 NP dimensions and their uniform dispersion across the SnO2 NW surface. This orchestrated approach yielded a remarkable 17-fold augmentation in the sensor's responsiveness towards 50 ppm acetone gas, as compared to sensors employing solely synthesized pure SnO2 NWs. Moreover, discernible sensor responses were adeptly elicited even at a minute concentration of 0.1 ppm acetone gas. A discernible advancement was discerned in contrast to antecedent research, reflecting substantial refinement in both response characteristics and the sensor's capacity to detect trace acetone gas levels. This heightened sensing proficiency can be attributed to the aptly tailored dimensions of Co3O4 NPs, harmoniously dispersed onto the SnO2 NW surface. This precise distribution engenders a pivotal p-n heterojunction, thereby eliciting the observed enhancement in sensing performance.

Fabrication of Pd-decorated tungsten oxide nanoflakes for hydrogen sensors via facile anodizing oxidation method

Accurate and reliable hydrogen sensing is crucial for safety and efficiency in industries like energy, transportation, and environmental monitoring. This study presents the synthesis and characterization of Pd-decorated WO3 nanoflakes with palladium (Pd) nanoparticles from anodizing derived WO3.2(H2O) nanoflakes for gas sensing applications. We investigate the crystal structure and phase composition of the synthesized nanoflakes using X-ray diffraction (XRD) and Raman spectroscopy, which confirm the presence of well-crystallized monoclinic WO3.2(H2O) phase without any impurities or secondary phases. Field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) reveal the unique morphology of the nanoflakes with irregular edges and varying sizes, as well as the successful decoration of Pd nanoparticles on the nanoflake surface. X-ray photoelectron spectroscopy (XPS) analysis indicates partial oxidation of tungsten species upon interaction with PdCl2 solution. We evaluate the gas sensing characteristics of the decorated nanoflakes towards hydrogen gas, demonstrating an enhanced response at elevated temperatures (>300 °C). The introduction of Pd nanoparticles improves the gas sensing response up to 6000 due to increased hydrogen dissociation and catalytic activity, as well as enhanced electrical conductivity. The response and recovery times of the sensors are rapid, indicating efficient response-recovery behavior. These findings suggest the potential of anodizing method for fabrication of WO3.2(H2O) nanoflakes as promising candidates for gas sensing applications.

Photochemical decoration of gold nanoparticles on MoS2 nanoflowers grafted onto the flexible carbon cloth as a recyclable SERS sensor for the detection of antibiotic residues on curved surfaces

Surface-enhanced Raman spectroscopy (SERS)-based flexible substrate has recently been demonstrated to be effective in detecting molecules on curved surfaces, however a suitable method for fabricating the flexible SERS substrate still remains a hurdle. In this paper, we fabricated a flexible SERS substrate by anchoring the plasmonic gold nanoparticles (Au-NPs) onto the hydrothermally grown flower-like molybdenum disulfide (MoS2) grafted onto carbon cloth (CC) via a facile photoreduction route. Benefitting from the abundant hotspots generation of the Au-NPs and photo-induced charge-transfer ability of MoS2, the constructed Au-NPs/MoS2/CC substrate exhibit a superior SERS sensing ability, excellent SERS enhancement factor, high flexibility and mechanical stability towards the nitrofurantoin (NFT) with an ultra-low detection limit of 10−11 M. As a trial for practical applications, the flexible substrate was used to detect NFT (10−4 M) in the curved surfaces of meat samples via swab technique. The ability of the flexible Au-NPs/MoS2/CC substrate to sustain the robust Raman signals of NFT even after recycling up to 4 cycles validated its reusability. The proposed flexible SERS substrate with reusable capability indicates its great potential in practical applications for the detection of target molecules on the curved surfaces.

Duple charge separation and plasmonically enriched DSSC and piezo-photocatalytic efficacy of Au anchored perovskite Gd3+:BiFeO3 nanospheres

Enhancing the solar-physical conversion efficacy ability of the nanomaterials is an essential for real-time implementation. We report the enhanced solar-physical efficiency of the BiFeO3 nanospheres via Gd3+ doping and Au nanoparticles decoration. Initially, we have obtained the Bi1-xGdxFeO3 nanospheres were attained via a simple solvothermal technique and then citrate reduction of Au was conducted. Obtained perovskite BiFeO systems were studied for the Gd3+ doping, crystalline phase and elemental purity using the XRD and XPS techniques. Transmission electron microscope had revealed the ∼400 nm sized BiFeO3 nanospheres. Optical absorption spectrum revealed the enhanced visible photon absorption occurring in BiFeO3 for both Gd3+ doping and Au decoration. The bandgap values of pristine, 1%, 3% and 5% Gd3+ doped in BiFeO3 are 2.2 eV, 2.19 eV, 2.17 eV and 2.12 eV, respectively. Conducted photoluminescence revealed the dual electron trapping occurring in BiFeO3 via Gd3+ ions and Au nanoparticles. LED light assisted 72% of piezo-photocatalytic degradation efficiency of Tetracycline is achieved with Bi0 95Fe0 05O3/Au, whereas the photo catalytic is only 65% and piezo catalytic efficiency is 58%. In recyclable studies the Bi0.95Gd0.05FeO3/Au had shown the consistent piezo-photocatalytic efficiency for 3 reaction cycles. Further, fabricated DSSC studies revealed that near 30 % enhanced solar photovoltaic efficiency for Bi0 95Fe0 05O3/Au (η = 6.5%) solar cells on par to the pristine BiFeO3 (η = 5.02%).

Pd-Nanoparticle-Decorated Multilayered MoS2 Sheets for Highly Sensitive Hydrogen Sensing

In this work, efficient hydrogen gas sensors based on multilayered p-type bare MoS2 and Pd-decorated MoS2 were fabricated. MoS2 was deposited onto alumina transducers using an airbrushing technique to be used as a sensing material. Aerosol-assisted chemical vapor deposition (AACVD) was used to decorate layered MoS2 with Pd nanoparticles at 250 °C. The bare and Pd-decorated MoS2 was characterized using field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and Raman spectroscopy. The characterization results reveal the multilayered crystalline structure of MoS2 with successful Pd decoration. The size of the Pd nanoparticles ranges from 15 nm to 23 nm. Gas sensing studies reveal that a maximum response of 55% is achieved for Pd-decorated MoS2 operated at 150 °C to 100 ppm of H2, which is clearly below the explosive limit (4%) in air. The higher sensitivity due to Pd nanoparticle decoration was owed to a spillover effect. This study reveals that the sensitivity of the sensors is highly dependent on the amount of Pd decoration. Moreover, sensor responses increase slightly when exposed to 50% relative humidity (RH at 25 °C).

Versatile electrode platform for determination of hydrogen peroxide in serum samples based on hemoglobin embedded in iron oxide/reduced graphene oxide nanocomposite

Hydrogen peroxide (H2O2) is a vital messenger molecule facilitating signal transmission within cellular systems. The accurate quantification of H2O2 in complex environments, such as human serum, is instrumental in elucidating its diverse biological functions. In this study, we present the development of a robust electrode platform by integrating hemoglobin onto iron oxide (Fe3O4) nanoparticles and reduced graphene oxide (rGO) as a conducting support for the sensitive detection of H2O2 in human serum. The Fe3O4/rGO nanocomposite was synthesized via a facile single-step thermolysis reaction in the presence of oleylamine. Transmission electron microscopy (TEM) analysis revealed the formation of highly monodisperse Fe3O4 nanoparticles that were uniformly dispersed over the reduced graphene surface. The rGO surface provided abundant active sites (Fe3O4) for H2O2 sensing. Consequently, the resulting Hb/Fe3O4@rGO modified electrode exhibited a wide linear range of H2O2 concentrations from 1.5 to 2684 µM, demonstrating high sensitivity and low detection limit. Further characterization of the Hb/Fe3O4@rGO/GC electrode revealed a high surface coverage (τ = 3.0 × 10−9 mol cm−2), charge transfer coefficient (α = 0.83), and electron transfer rate constant (ks = 1.33 s−1). Subsequently, the Hb/Fe3O4@rGO/GC sensor probe was employed to analyze H2O2 in real human serum samples, demonstrating excellent recovery rates ranging from 99.8 % to 104.0 %. The nanocomposite material, designed through the innovative combination of graphene oxide reduction, Fe3O4 nanoparticle decoration, and oleylamine amide/amine bonding, serves as an excellent electrode material for H2O2 concentration sensing. Thus, this study presents a promising platform for the future determination of H2O2 biomarkers in clinical settings.

Enhanced photocatalytic performance of milkvetch-derived biochar via ZnO–Ce nanoparticle decoration for reactive blue 19 dye removal

In this research, the photocatalytic removal of reactive blue 19 (RB19) dye is investigated employing zinc oxide/cerium (ZnO@Ce) nanoparticles decorated with biochar under LED irradiation. Synthesis of ZnO@Ce nanoparticles decorated with biochar was performed utilizing the co-precipitation procedure and, then, the texture and morphology of the fabricated nanocomposite were analyzed using energy dispersive X-ray (EDX), field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), and Fourier transform infrared (FTIR) spectroscopy techniques. Moreover, FE-SEM images demonstrate that ZnO–Ce nanoparticles were successfully decorated on the surface of biochar. The specific surface areas of biochar and biochar/ZnO–Ce were 519.75 and 636.52 m2/g, respectively. To achieve the maximum yield in the removal of RB19 dye, the effects of operating variables including dye concentration, LED lamp power, biochar@ZnO–Ce catalyst dose, pH and H2O2 dose were explored. Besides, the maximum percentage of RB19 dye removal was 96.47% under optimal conditions, i.e. catalyst dosage of 100 mg, H2O2 dosage of 1 mL, pH of 9, initial dye concentration of 5 ppm, LED power of 50 W, and reaction time of 140 min. Furthermore, the kinetic analysis reveals that the removal of RB19 dye follows the pseudo-first order kinetic model, with calculated values of a reaction rate constant of 0.045 min−1 and a correlation coefficient of R2 = 0.99, respectively. Moreover, the reusability and recyclability of biochar@ZnO/Ce nanocatalyst was promising over five runs, with only a 6.08% decrease in RB19 dye removal efficiency. Therefore, it can be concluded that the biochar @ZnO/Ce photocatalyst can be promisingly applied for the removal of azo dyes in aqueous solutions.

Mesostructured graphitic carbon nitride composites with silver nanoparticle decoration as the best visible-light-driven photocatalysts for dye degradation and H2 production

Water-splitting photocatalysis on the surface of semiconductors has emerged as a promising approach for wastewater treatment to remove organic pollutants from aqueous media in various industrial fields. However, developing efficient photocatalysts with sufficient activity is challenging owing to the rapid recombination of photogenerated electrons and holes in the available functional materials. Aiming to fabricate photocatalysts to remove pollutants with reduced electron-hole recombination, mesostructured graphitic carbon nitride (MCN) composites made of Ag-doped melamine were designed and synthesized at room temperature. The structural and optical properties of the prepared MCN composite indicate that it is well-suited for use as a visible-light-driven photocatalyst. A morphological analysis using transmission and scanning electron microscopy showed that the Ag nanoparticles were uniformly distributed on the surface of the MCN sheets, promoting the photocatalytic property of the Ag/MCN composites. Adding silver nanoparticles onto MCN facilitates the rapid transfer of photo-generated electrons from MCN to the silver nanoparticles. This is due to the presence of an interfacial electric field across the junctions, leading to a reduction in the recombination process, resulting in superior photocatalytic activity in the degradation of reference organic pollutants like methylene blue and crystal violet, more than 96% of degradation was achieved in the presence of the MCN\\Ag-MCN composite. An astonishing photocatalytic hydrogen evolution rate of 5.24 mmol. g−1.h−1 was observed for the optimized MCN/Ag-MCN nanocomposite.