Greater Photocatalytic Activity Research Articles

Multiple strategy for antibacterial effect via copper porphyrin doping polyphenolic aldehydes based covalent organic framework

Microbial infections continue to be one of the cosmopolitan safety hazards to humankind. To achieve effective sterilization, it is urgent to develop non-antibiotic strategies or integrating multiple antimicrobial methods. Organic photo-antimicrobials (OPAMs) has attracted attention in fighting against bacteria by reactive oxygen species (ROS) or heat without triggering drug resistance. In our work, a copper-porphyrin doping donor-acceptor (D-A) type covalent organic framework (COF), named CTF-BTA2OH-Por(Cu), is constructed to achieve synergistic antibacterial effects by ROS generation and protein degradation. Copper-porphyrin doping improves ROS generation of D-A COF, showing great photocatalytic antibacterial activity (>90 % within 1 h). Additionally, the polyphenolic aldehydes of BTA2OH can interact with protein strongly and cause degradation, resulting inhibition of bacteria growth without light. Thus, CTF-BTA2OH-Por(Cu) showed antibacterial activity under both light and dark conditions. These findings give inspiration for COF multifunctional design for antimicrobials strategy and its application in supplies anti-infection or preservation.

Synthesis of pure and Cd-doped hydroxyapatite for the photo-catalytic degradation of Amoxicillin and Ciprofloxacin: Crystallographic characterization using XRD

Nanosized hydroxyapatite (HAp) is considered an elementary material for artificial bone tissue engineering and the applications are expanding and one of them is the photocatalytic degradation of environmentally hazardous pollutants. In this research, HAp nanoparticles, in pure form and doped with cadmium (Cd), were synthesized using a conventional wet-chemical precipitation method. Additionally, the synthesized samples such as pure and Cd-doped HAp were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis spectroscopy. Moreover, the XRD analysis allowed for a detailed estimation of the crystallite size, assisting in their tailoring of increased photocatalytic activity. The crystallite sizes of the nano-crystallite Hap were evaluated using the Scherrer Method (SM), Williamson-Hall Method (WHM), Size-Strain Plot (SSP), Halder-Wagner Method (HWM), and Sahadat-Scherrer Method (SSM). The models confirmed the formation of nano crystallite hydroxyapatite in pure and doped form. Cadmium doping in HAp showed great photocatalytic activity for example at 150 min, 31 % amoxicillin and 52 % ciprofloxacin were degraded upon 1.5 wt % Cd doping in HAp crystal. The research demonstrated that doping Cd in HAp crystal improved photocatalytic activity towards antibiotic solution (ciprofloxacin and amoxicillin) under all test circumstances.

A new perspective for surface modifying TiO2 to effectively enhance its visible light photocatalytic activity

In this study, a new perspective was proposed to regulate the photocatalytic properties of TiO2 and a novel TiO2-based composite (BA@TiO2) with nitrogen-containing surface layer was obtained by surface modifying TiO2 with an organic molecular (3,3′-Diaminobenzidine, BA). The composite (BA@TiO2) exhibited high responsiveness to visible light and great photocatalytic activity, which could remove 92% of tetracycline hydrochloride (TC), and also maintained a high ability to photodegrade low concentrations of TC. The free radical trapping experiments showed that h+ and •O2- were the most dominant active species in the degradation process. The possible degradation pathways of TC were deduced with the help of HPLC-MS and fuikui index. QSAR was used to perform toxicity analysis of the degradation intermediates. In addition, the composites demonstrated good recyclable stability and removal efficiency of TC in real water samples, indicating BA@TiO2 is a purifying agent with great efficiency and sustainability for practical treatment of organic pollutants in aqueous media.

One-Dimensional Shaving-like BiVO4 Nanobelts: Synthesis, Characterization and Photocatalytic Activity with Methylene Blue

One-dimensional shaving-like BiVO4 nanobelts were successfully synthesized via the oxide hydrothermal method (OHS), using V2O5 and Bi2O3 as raw materials and PEG 10000 (polyethylene glycol 10000) as a template. Multiple techniques, including XRD, SEM, TEM, HRTEM, UV–Vis, XPS, and photoelectrochemical measurements, were applied to characterize the obtained materials. The thickness of the BiVO4 nanobelt was approximately 10 nm, while the width was approximately 500 nm. EIS results showed that visible-light illumination caused the photogenerated charge of the BiVO4 nanobelts to have a faster transfer and a higher separation efficiency. Photocatalytic experiments indicated that with BiVO4 nanobelts as a catalyst, the degradation rate of MB (methylene blue) was close to 92.4%, and it disintegrated after two hours. Moreover, the pseudo-first-order kinetic model can be used to describe the photodecomposition reaction of MB catalysed by BiVO4 nanobelts. And this excellent photocatalytic activity of the shaving-like BiVO4 nanobelts may be related to their special morphology, narrow band gap (~2.19 eV), faster transfer and the separation efficiency of the photogenerated charge, leading to strong absorption in the visible region and improving the separation of the photogenerated electron–hole pairs. These novel monoclinic BiVO4 nanobelts exhibited great photocatalytic activity and are thus a promising candidate for application in visible-light-responsive photocatalysts.

Sonochemical Synthesis, Characterization, and Photocatalytic Performance Evaluation of Au/ZnO Nanocomposite for Methyl Orange Degradation

This study examines the impact of gold (Au) incorporation on zinc oxide (ZnO) nanoparticles. Both pure ZnO and Au/ZnO nanocomposite have been synthesized using a unique and environmentally friendly sonochemical approach. The as-synthesized Au/ZnO nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) spectroscopic techniques. Under UV-visible irradiation, the photocatalytic effectiveness of ZnO nanoparticles and Au/ZnO nanocomposites for the degradation of dye was examined. The results demonstrated that the nanocomposite has greater photocatalytic activity than ZnO nanoparticles. This is due to the effective electron transfer from ZnO to Au prolonging the lifetime of photogenerated holes, which play the most important role in the dye degradation process.

Constructing MXene-derived Z-Scheme g-C3N4/Ti3C2TX/Ag3PO4 photocatalysts with enhanced charge transfer for aquatic organic pollutants removal

Photocatalysis was considered an efficient and environmentally friendly technology for wastewater treatment. In this study, MXene-derived g-C3N4/Ti3C2TX/Ag3PO4 as a novel Z-type heterojunction photocatalyst is successfully constructed, which shows great photocatalytic activity under visible light irradiation. Besides, Ti3C2TX could serve as an “electron bridge” between g-C3N4 and Ag3PO4, where the well-matched energy levels could be connected, improving the charge transfer rate remarkably. Meanwhile, PL, EIS and TPR results showed that Ti3C2TX possessed high electrical conductivity, which acted as an electron bridge between g-C3N4 and Ag3PO4 to improve the separation efficiency of photogenerated carriers, resulting in higher photocatalytic activity. Besides, g-C3N4/Ti3C2TX/Ag3PO4 exhibited extensive degradability to pharmaceutical and personal care products (PPCPs) and azo dyes including methylene blue (100.0%), rhodamine B (92.16%), tribromophenol (97.43%), ibuprofen (87.98%), doxycycline hydrochloride (57.97%) and levofloxacin (80.73%). In addition, g-C3N4/Ti3C2TX/Ag3PO4 showed great recycling ability, no obvious difference was observed after five consecutive cycles of degradation experiments. Moreover, the reactive oxygen species (ROS) including hydroxyl radicals (•OH), holes (h+) and superoxide radicals (•O2−) during the degradation process were confirmed by ESR analysis and trapping experiments, and a possible photocatalytic mechanism of g-C3N4/Ti3C2TX/Ag3PO4 heterojunction photocatalyst under visible light irradiation was also proposed.

A new formulation of Ni/Zn bi-metallic nanocomposite and evaluation of its applications for pollution removal, photocatalytic, electrochemical sensing, and anti-breast cancer

Nanocomposites have gained attention due to their variety of applications in different fields. In this research, we have reported a green synthesis of a bi-metallic nanocomposite of nickel and zinc using an aqueous extract of Citrus sinensis in the presence of chitosan (Ni/Zn@orange/chitosan). The nanocomposite was characterized using different techniques. We have examined various applications for Ni/Zn@orange/chitosan. The NPs were manufactured in spherical morphology with a particle range size of 17.34–90.51 nm. Ni/Zn@orange/chitosan showed an acceptable ability to remove dyes of Congo red and methyl orange from an aqueous solution after 80 min furthermore, it uptaking the drug mefenamic acid from a solution. Ni/Zn@orange/chitosan also exhibited great photocatalytic activity in synthesizing benzimidazole using benzyl alcohol and o-phenylenediamine. Ni/Zn@orange/chitosan was found as a potent electrochemical sensor to determine glucose. In the molecular and cellular section of the current research, the cells with composite nanoparticles were studied by MTT way about the anti-breast adenocarcinoma potentials malignant cell lines. The IC50 of composite nanoparticles were 320, 460, 328, 500, 325, 379, 350, and 396 μg/mL concering RBA, NMU, SK-BR-3, CAMA-1, MCF7, AU565, MDA-MB-468, and Hs 281.T breast adenocarcinoma cell lines, respectively. The results revealed the newly synthesized nanocomposite is a potent photocatalyst, dye pollution removal agent, and an acceptable new drug to treat breast cancer.

One-step synthesis of porous thin-layered graphitic carbon nitride for enhanced photocatalytic dye degradation

The application of graphitic carbon nitride (g-C3N4) as a non-metallic photocatalyst for removing harmful pollutants in the wastewater environment has received considerable attention in recent years. Nevertheless, its low activity is primarily restricted by a high rate of charge carrier recombination. Herein, a green and straightforward method for synthesizing small-sized porous thin g-C3N4 nanosheets directly from urea solution has been developed. This new photocatalyst can effectively remove 99.3% of rhodamine B within 15 min, exhibiting a degradation rate 16.8 times greater than that of conventionally synthesized bulk g-C3N4, under visible light irradiation. Additionally, this photocatalytic efficiency is comparable or even superior to that of previously reported literature, while requiring significantly less catalyst usage. From the experimental results, we have confirmed that the outstanding structural property as well as the stronger oxidizability of the valence-band holes (h+) are responsible for its greater photocatalytic activity. Its increased specific surface area and abundant pore structure significantly improve contaminant adsorption and charge separation and transfer. Meanwhile, the positive shift of the valence band enhances the oxidation of photogenerated h+, resulting in higher photocatalytic activity. This work can provide newly insights for designing highly efficient and easily-constructed g-C3N4 photocatalysts for practical photocatalytic water treatment applications.

Enhanced visible light catalytic activity of holey Ti3C2 based catalyst for azo dyes

The efficient degradation of organic dye pollutions is of great importance for environmental remediation. In this work, we prepared holey Ti3C2 (H-Ti3C2) and further synthesized H-Ti3C2/Ag/AgX (Cl, Br, I) Schottky catalysts by a simple electrostatic self-assembly method, and found that H-Ti3C2 could significantly improve the catalytic activity and stability of AgX. The H-Ti3C2/Ag/AgX composites showed great visible light absorption, obvious photocurrent intensity, and high charge transfer efficiency, ultimately improving photocatalytic efficacy for the degradation of methyl orange (MO) dye. The composite (5 wt%) H-Ti3C2/Ag/AgBr has the greatest photocatalytic activity, degrading 99.2% of the MO solution after 40 min of visible light irradiation, which is 1.08 and 2.02 times more than (5 wt%) Ti3C2 /Ag/AgBr and Ag/AgBr, respectively. The photocatalytic performance of H-Ti3C2/Ag/AgBr for MO dyes remains at 51% after five cycles. This result indicates that combining H-Ti3C2 with other photosensitive semiconductors to improve the catalytic activity and stability offers great possibilities. The present work not only provides a simplified method for the preparation of H-Ti3C2/Ag/AgX composites, but also offers a great possibility for H-Ti3C2 MXene as a co-catalyst to increase the photocatalytic degradation efficiency of organic pollutants.

Hierarchical Ultrathin Layered GO-ZnO@CeO2 Nanohybrids for Highly Efficient Methylene Blue Dye Degradation.

Highly efficient interfacial contact between components in nanohybrids is a key to achieving great photocatalytic activity in photocatalysts and degradation of organic model pollutants under visible light irradiation. Herein, we report the synthesis of nano-assembly of graphene oxide, zinc oxide and cerium oxide (GO-ZnO@CeO2) nanohybrids constructed by the hydrothermal method and subsequently annealed at 300 °C for 4 h. The unique graphene oxide sheets, which are anchored with semiconducting materials (ZnO and CeO2 nanoparticles), act with a significant role in realizing sufficient interfacial contact in the new GO-ZnO@CeO2 nanohybrids. Consequently, the nano-assembled structure of GO-ZnO@CeO2 exhibits a greater level (96.66%) of MB dye degradation activity than GO-ZnO nanostructures and CeO2 nanoparticles on their own. This is due to the thin layers of GO-ZnO@CeO2 nanohybrids with interfacial contact, suitable band-gap matching and high surface area, preferred for the improvement of photocatalytic performance. Furthermore, this work offers a facile building and cost-effective construction strategy to synthesize the GO-ZnO@CeO2 nanocatalyst for photocatalytic degradation of organic pollutants with long-term stability and higher efficiency.

A Study of the Optical and Structural Properties of SnO2 Nanoparticles Synthesized with Tilia cordata Applied in Methylene Blue Degradation

Water contamination is one of the most worrisome problems in the world. Industrial dyes are discharged without previous treatment, promoting water pollution and affecting the environment. In this paper, semiconductor SnO2 nanoparticles (NPs) were synthesized using Tilia cordata extract, as a reducing agent, at different concentrations, 1%, 2%, and 4% (weight/volume; w/v). These NPs were used as photocatalysts characterize an alternative for degrading wastewater compounds. Nanoparticle symmetry is an important factor for understanding the properties that provide tools for further treatments. Additionally, the structural, morphological, and optical properties of the green-synthesized SnO2 NPs were studied. Fourier transform infrared spectroscopy (FTIR) showed the characteristic absorption band of Sn–O centered at 609 cm−1. Meanwhile, X-ray diffraction (XRD) confirmed a tetragonal rutile-type crystalline phase without impurities whose crystallite size increased from 15.96 nm and 16.38 nm to 21.51 nm for SnO2-1%, SnO2-2%, and SnO2-4%, respectively, as extract concentration was increased. NPs with a quasi-spherical morphology with agglomerations were observed through scanning electron microscopy (SEM). On the other hand, the bandgap remained at ~3.6 eV throughout all samples, even at variable extract concentrations. The NPs yielded great photocatalytic activity capable of degrading methylene blue (MB) dye under ultraviolet radiation and solar radiation, achieving degradation percentages of 90% and 83% of MB under UV and solar radiation at 90 and 180 min, respectively.

Synthesis of Ag/ZnO nanocomposites with enhanced visible photocatalytic performance

Ag/ZnO photocatalysts with different silver content (0, 1, 2, and 3 mol%) were fabricated through a hydrothermal method. Characterization results of XRD showed the ZnO was a hexagonal wurtzite structure, and the Ag was a face-centered cubic (fcc) structure. The morphologies results suggested that the particles with nonuniform shapes (nano-rods, nano-spheres, and nano-sheets). UV–Vis DRS absorbance spectra unveiled a decrease in the band gap for Ag/ZnO with the introduction of Ag, indicating the improvement of visible light absorption. All Ag/ZnO samples demonstrated great photocatalytic activity (the highest reached 96.7% within 40 min) and were better than commercial ZnO and as-prepared ZnO samples. The introduction of Ag nanoparticles with the surface plasmon resonance (SPR) effect can significantly improve the photocatalytic performance for Ag/ZnO photocatalysts. Moreover, ·O2− was proved to be the primary active group in the photoreaction. The Ag/ZnO photocatalysts also had good recycling stability and still maintained a high photodegradation rate (93.7%) after five recycles.

Coupling the bioanode and S-scheme CuO/CdS quantum dots photocathode for chlortetracycline degradation: Performance, mechanism and microbial community

The quantum dots (QDs) modified S-scheme CuO/CdS photocathode was fabricated and integrated with a bioanode in the bio-photoelectrochemical system (BPES) for chlortetracycline (CTC) degradation under simulated solar irradiation using NaHCO3 as buffer. The S-scheme CuO/CdS QDs heterojunction was demonstrated by work function calculation and electron spin-resonance spectroscopy (ESR) test. The optimized CuO/CdS QDs photocathode exhibited great photocatalytic activity toward CTC degradation, due to its unique small-size effect, efficient light absorption, and efficient carriers separation and transfer. Results of ESR test demonstrated that hydroxyl (·OH), superoxide (·O2-) and carbonate radicals (·CO3-) could be produced by the photocathode, and they all contributed to CTC degradation. The degradation rate of CTC by BPES was 1.29 times that of the unilluminated system (86.8% vs 67.1%), and the maximum current density was 2.3 times (3.42 vs 1.48 A/m2). The dominant bacterial species in the CTC degradation of BPES were Pseudomonas and Acinetobacter. Possible mechanism and pathways of CTC degradation were proposed. This study advances the development of BPESs for antibiotics degradation.

Synthesis of Polyaniline Supported CdS/CdS-ZnS/CdS-TiO2 Nanocomposite for Efficient Photocatalytic Applications.

Photocatalytic degradation can be increased by improving photo-generated electrons and broadening the region of light absorption through conductive polymers. In that view, we have synthesized Polyaniline (PANI) with CdS, CdS-ZnS, and CdS-TiO2 nanocomposites using the chemical precipitation method, characterized and verified for the photo-degradation of Acid blue-29 dye. This paper provides a methodical conception about in what way conductive polymers “PANI” enhances the performance rate of composite photocatalysts (CdS, CdS-ZnS and CdS-TiO2). The nanocomposites charge transfer, molar ratio, surface morphology, particle size, diffraction pattern, thermal stability, optical and recombination of photo-generated charge carrier properties were determined. The production of nanocomposites and their efficient photocatalytic capabilities were observed. The mechanism of photocatalysis involved with PC, CZP and CTP nanocomposites are well presented by suitable diagrams representing the exchange of electrons and protons among themselves with supported equations. We discovered that increasing the number of nanocomposites in the membranes boosted both photocatalytic activity and degradation rate. CdS-Zinc-PANI (CZP) and CdS-TiO2-PANI(CTP) nanocomposites show entrapment at the surface defects of Zinc and TiO2 nanoparticles due to the demolition of unfavorable electron kinetics, and by reducing the charge recombination, greater photocatalytic activity than CdS-PANI (CP) with the same nanoparticle loading was achieved. With repeated use, the photocatalysts’ efficiency dropped very little, hinting that they may be used to remove organic pollutants from water. The photocatalytic activity of CZP and CTP photocatalytic membranes was greater when compared to CdS-PANI, which may be due to the good compatibility between CdS and Zinc and TiO2, as well efficient charge carrier separation. PANI can also increase the split-up of photo-excited charge carriers and extend the absorption zone when combined with these nanoparticles. As a result, the development of outrageous performance photocatalysts and their potential uses in ecological purification and solar power conversion has been facilitated. The novelty of this article is to present the degradation of AB-29 Dye using nanocomposites with polymers and study the enhanced degradation rate. Few studies have been carried out on polymer nanocomposites and their application in the degradation of AB-29 dyes and remediation of water purposes. Nanoparticle CdS is a very effective photocatalyst, commonly used for water purification along with nanoparticle ZnS and TiO2; but cadmium ion-leaching makes it ineffective for practical and commercial use. In the present work, we have reduced the leaching of hazardous cadmium ions by trapping them in a polyaniline matrix, hence making it suitable for commercial use. We have embedded ZnS and TiO2 along with CdS in a polyaniline matrix and compared their photocatalytic activity, stability, and reusability, proving our nano-composites suitable for commercial purposes with enhanced activities and stabilities, which is a novelty. All synthesized nanocomposites are active within the near-ultraviolet to deep infrared (i.e., 340–850 nm). This gives us full efficiency of the photocatalysts in the sunlight and further proves the commercial utility of our nanocomposites.

Hydroxyl radical and carbonate radical facilitate chlortetracycline degradation in the bio-photoelectrochemical system with a bioanode and a Bi2O3/CuO photocathode using bicarbonate buffer

The single-chamber bio-photoelectrochemical system (BPES) with a bioanode and a Bi2O3/CuO photocathode is developed for chlortetracycline (CTC) degradation under simulated solar irradiation, using phosphate buffer solution (PBS) or NaHCO3 as buffer solution. The optimized Bi2O3/CuO photocathode possesses rich vacancies, great photoresponse capability, and exhibits great photocatalytic activity toward CTC degradation due to its Z-scheme structure. Electron spin-resonance spectroscopy (ESR) and reactive species trapping experiments reveal that superoxide radicals/hydroxyl radicals are both the main radicals contributing to CTC degradation. Moreover, carbonate radical plays a more effective role toward CTC degradation, resulting in 40% improvement for CTC degradation in the BPES within 2 h. Higher current density (maximum of 137.6 A m−2) and more negative cathode potential are obtained from the illuminated BPES with NaHCO3 buffer. Possible mechanism and pathways of CTC degradation are proposed. This study contributes to the development of BPESs for antibiotics degradation.

Study of the optical properties of TiO2 semiconductor nanoparticles synthesized using Salvia rosmarinus and its effect on photocatalytic activity

In recent years, the green synthesis of nanomaterials has gained interest as an efficient and environmentally friendly method for obtaining metal oxide nanoparticles. This work presents a study on the effect of Salvia rosmarinus extract in the optical properties and photocatalytic activity of titanium oxide (TiO2) nanoparticles (NPs) synthetized through a green route. Titanium tetrachloride (TiCl4) was used as the Ti source, while Salvia rosmarinus extract with different amounts (1%, 2%, and 4% w/v) was used as a stabilizing agent. Fourier-transform infrared spectroscopy (FTIR) characterization shows the presence of the Ti–O–Ti band at 408 cm−1, while X-ray diffraction (XRD) results identified the crystalline structure of anatase phase TiO2 with no impurities and scanning electron microscope (SEM) images showed a spherical shape with agglomerations. The calculated band gap values decreased from 3.21 eV to 2.93 eV as the extract concentration increased. The NPs showed great photocatalytic activity under solar irradiation, achieving over 90% degradation for methylene blue (MB) in just 20 min. Additionally, the NPs showed great degradation of methyl orange (MO), and rhodamine B (RhB) under UV irradiation, with the best sample reaching over 90% degradation in under 60 min of exposure.

Solar light–driven photocatalysis using BaFe2O4/rGO for chlorhexidine digluconate–contaminated water: comparison with artificial UV and visible light–mediated photocatalysis

Synthesis and characterization of dual functioning material is an effective approach for the promotion of organic pollutant degradation through adsorption as well as photocatalysis. Herein, graphene oxide was modified by the addition of barium nitrate and iron to construct a smooth sheet-like structure (BaFe2O4/rGO) for the removal of chlorhexidine digluconate (CHD). Compared with GO (75.69%-UV light; 88.17%-visible light), BaFe2O4/rGO showed significant adsorption-photocatalysis effect under visible light (93.95%) than that under UV light (78.17%). The introduction of barium nitrate and iron into graphene oxide leads to a smooth porous structure with increased surface area (93.66 m2g-1), which resulted in a large number of adsorption active sites and great photocatalytic activity with efficient charge separation. Although catalysts did not mineralize CHD completely, butthe parent compound mineralized to some extent, which was confirmed by the TOC measurement and UV254 absorbance variation. In addition, toxicity of degraded products was analysed by bacterial susceptibility test on Bacillus cereus DPAML065, suggesting that nontoxic by-products of CHD were formed, which leads to their safe disposal. Based on the identified transformed products, the possible degradation pathway was proposed. Batch studies demonstrated that BaFe2O4/rGO is highly photoactive based on reaction rate constant (R2 = 0.984), where the kinetics data were well-fitted using the pseudo-first order. Moreover, efficiency of catalysts was examined under solar light to achieve the sustainability.

Photocatalytic hydrogen generation using colloidal covalent organic polymers decorated bimetallic Au-Pd nanoalloy (COPs/Pd-Au)

Photocatalytic H2 generation has been considered as an effective method for H2 generation, in which the cocatalysts play a critical role. Here, we report highly reactive nanocomposites composed of two-dimensional triazine-based covalent organic Polymers (COPs), Pd and Au nanocomponents which is designed to benefit from the alloying and visible light illumination effects as well as LSPR effect. Photocatalytic hydrogen production was achieved under low-cost visible light-driven. The COP/Pd-Au exhibited higher photocatalytic outstanding turnover frequency of 260.5 h − 1, which was 1.47 times of that under no light (177.3 h − 1). Additionally, it exhibits much advanced catalytic performance, which is 2.83-fold that of COP/Pd (91.98 h − 1) and 434.17-fold that of COP/Au (0.60 h − 1), under the similar reaction conditions. The great photocatalytic activity for COP/Pd-Au was also ascribed to the strong interface between Pd-Au NPs and COPs, and the preparation of single hollow construction of Pd-Au alloy with porous nature that presented active sites for hydrogen production.

Enhanced the photocatalytic degradation of titanium dioxide nanoparticles synthesized by different plant extracts for wastewater treatment

Biological synthesis pathway was used to successfully prepare titanium dioxide nanoparticles (TiO2 NPs) as a simple synthetic process, employing three distinct aqueous extracts: pomegranate (Pom), Beta vulgaris (V.B), and Seder. In addition, typical TiO2 NPs were made using a simple wet chemical approach for comparison. Different characterization techniques, such as UV–Vis spectroscopy, XRD, FT-IR, and TEM, were used to examine all of the TiO2 NPs that were generated either through the biologically or chemically route. For all the synthesized samples, the observed XRD results reveal a tetragonal structure with two phases, rutile and anatase. The particle sizes of the materials developed range from 15.2 to 20.6 nm. The obtained results suggested that the nature of plant extract predisposes the altered aspects of the manufactured particles, such as photocatalytic, particle size, and the ratio between two phases. FT-IR spectroscopy validated the biomolecules elaborated in the biosynthetic method. In the presence of UV irradiation, the photocatalytic activities of NPs were studied using Methyl Orange (MO) organic dye as an example of water pollutant. As a result of the lower mass fraction of rutile phase, the green generated TiO2 NPs had greater photocatalytic activity and efficiency in the photodegradation of MO compared to the chemically synthesized TiO2 NPs samples. The photocatalytic destruction of the assembled NPs was discovered to follow pseudo-first order kinetics trend, with efficiency exceeding that of ultraviolet light. Moreover, the obtained results confirmed that the prepared TiO2 NPs based on biological sources are considered as a promising candidate aimed at removal of organic pollutants from water and can be applied in waste water treatment applications.

Glucose-tailored SnO2/TiO2/RGO ternary composite for degradation of organic pollutants

A glucose-tailored SnO2/TiO2/reduced graphene oxide ternary composite is developed for a high-performance photocatalyst. First, SnO2 nanoparticles are deposited on graphene oxide nanosheets through a hydrolysis method. In the presence of glucose, TiO2 nanoparticles are synthesized on SnO2/graphene oxide via a hydrothermal reaction. The influence of glucose dose and Sn/Ti ratio on the photocatalytic performance is studied. When used for degradation of rhodamine B and methylene blue, the optimized composite exhibits much greater photocatalytic activity than commercial P25, and degrades 97.6% of rhodamine B and 99.5% of methylene blue in 40 min. The superior performance is attributed to the tailored microstructure and SnO2/TiO2 heterojunction. Glucose prevents the stacking of graphene nanosheets, adjusts the pore structure, and results in the formation of a composite with a large specific surface area and hydrophilicity, which facilitates dispersion of the catalyst powder in water and improves the physical adsorption to dye molecules. Furthermore, the SnO2/TiO2 heterojunction formed on conductive reduced graphene oxide reduces the band gap and broadens the light absorption range, reduces the charge transfer resistance, and promotes the separation and transfer of carriers. Moreover, ·O2− and ·OH radicals are both generated for degradation of organic pollutants through a redox reaction. Finally, a possible photodegradation mechanism is proposed as a Z-scheme transfer mode.