UV Vis Diffuse Reflectance Spectra Research Articles

Influence of Synthesis Conditions on Physicochemical and Photocatalytic Properties of Ag Containing Nanomaterials

Silver (Ag) containing nanomaterials were successfully prepared by varying synthesis conditions to understand the influence of preparation conditions on the physicochemical and photocatalytic properties of these materials. Different analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Diffuse reflectance UV-vis spectra (DR UV-vis), X-ray photoelectron spectroscopy (XPS) measurements, and N2-physisorption were used to investigate the physicochemical properties of synthesized Ag containing nanomaterials. The samples (Ag-1 and Ag-2) prepared using AgNO3, NaHCO3, and polyvinylpyrrolidone (PVP) template exhibited pure Ag metal nanorods and nanoparticles; the morphology of Ag metal is influenced by the hydrothermal treatment. The Ag-3 sample prepared without PVP template and calcined at 250 °C showed the presence of a pure Ag2O phase. However, the same sample dried at 50 °C (Ag-4) showed the presence of a pure Ag2CO3 phase. Interestingly, subjecting the sample to hydrothermal treatment (Ag-5) has not resulted in any change in crystal structure, but particle size was increased. All the synthesized Ag containing nanomaterials were used as photocatalysts for p-nitrophenol (p-NP) degradation under visible light irradiation. The Ag-4 sample (pure Ag2CO3 with small crystallite size) exhibited high photocatalytic activity (86% efficiency at pH 10, p-NP concentration of 16 mg L−1, 120 min and catalyst mass of 100 mg) compared to the other synthesized Ag containing nanomaterials. The high photocatalytic activity of the Ag-4 sample is possibly due to the presence of a pure Ag2CO3 crystal structure with nanorod morphology with a low band gap energy of 1.96 eV and relative high surface area.

A naphthalenediimide-based Cd-MOF as solvatochromic sensor to detect organic amines

A novel naphthalenediimide-based metal-organic framework, {[Cd(DPNDI)(2,6-NDC)]·2DMF}n (1), has been constructed from mixed ligands of N,N′-Di(4-pyridyl)-1,4,5,8-naphthalene -tetracarboxydiimide (DPNDI) and naphthalene-2,6-dicarboxylic acid (2,6-NDC). 1 displays a two-fold interpenetrated 3D framework related to the 6-c connected pcu topology, which exhibits solvatochromic behavior in the presence of organic amines (electron rich). This solvatochromic behavior was investigated by solid state UV–Vis diffuse reflectance spectra and photo-luminescent spectra, which was arise from the inter-molecular electron-transfer transition from the different solvents to the DPNDI ligand depending on the electron-donating ability of the guest solvents. This work shows that the naphthalenediimide-based MOFs could be used as solvatochromic sensor to detect organic amines.

Surface modification of Cu2O-CuO photocatalyst on Cu wire through decorating with TiO2 nanoparticles for enhanced visible light photocatalytic activity

In this paper, the fabrication of Cu2O-CuO/TiO2 nanocomposite photocatalysts on Cu wire was performed successfully via chemical-thermal oxidation and sol-gel process. The chemical-thermal oxidations were applied for Cu2O-CuO nanostructure fabrication on the Cu wire surface. The sol-gel process was utilized for TiO2 nanoparticles decoration as a surface modification process for photocatalytic activity improvement. The X-ray diffraction analysis (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) showed the coexistence of multiple components including Cu2O, CuO, Cu, and TiO2 in the nanocomposite. Field emission electron scanning microscopy (FESEM) results demonstrated remarkable changes in morphology by applying different preparation conditions. The calculated band gap energies from UV–vis diffuse reflectance spectra (DRS) were in the range of 1.72–1.96 eV demonstrating their activity under visible light illumination. Photoluminescence (PL) data indicated delayed recombination of electrons - holes with surface modification due to the formation of heterostructure in the nanocomposite. The investigation of the photocatalytic performance was performed by methylene blue (MB) and methylene orange (MO) dye degradation under visible light illumination and 87 % degradation efficiency was obtained after 120 min. The active species trapping tests involving scavengers demonstrated that the superoxide radicals and holes play more noticeable roles compared to hydroxyl radicals in photocatalytic degradation. The ability to easily separate photocatalyst wires from aqueous solution along with good stability after several cycles of use in degradation is a unique feature of the prepared photocatalysts.

Synthesis and characterization of Ni-doped TiO2 activated carbon nanocomposite for the photocatalytic degradation of anthracene

Nickel-doped titanium dioxide nanoparticles (NDT) deposited on pine cone activated carbon (PAC) have been successfully synthesized by a hydrothermal method. The as synthesized nanocomposite was characterized by X-ray diffraction pattern (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron (XPS), Fourier transform infrared (FT-IR), UV–visible diffuse reflectance spectra (UV–vis DRS), Photoluminescence (PL), BET surface area, and pHzpc. The characterization results of the prepared nanocomposite revealed that Ni-TiO2 was loaded on the surface of PAC, and had a higher surface area and narrower bandgap than TiO2 nanoparticles. The visible-light photocatalytic activity of the Ni-TiO2@C nanocomposite towards anthracene degradation was found to be 99.9% in 50 mins leading to end products of (1E, 3Z)-hexa-1,3,5-trien-1-ol (1a; m/z = 96), and (1E, 3E)-penta-1,3-dien-1-ol. The synthesized Ni-TiO2@C nanocomposite exhibited a better photocatalytic activity towards the photocatalytic degradation of anthracene as compared to the TiO2 nanomaterial (22.5%) and TiO2/activated carbon nanocomposite (31%) under similar conditions. The photodegradation of anthracene followed the pseudo first-order rate kinetics. The Ni-TiO2@C nanocomposite had excellent regeneration properties till the fifth cycle of use during which it degraded around 73% anthracene.

SnO2 Nanoparticles: Green Synthesis, Characterization, and Water Treatment

The green synthesis approach was utilized to synthesize tin dioxide (SnO2) nanoparticles (NPs) using Ocimum Basilicum leaves extract with different concentrations (10, 15, 20 ml) and different reaction temperatures (30, 60, 90 °C). The green synthesis method is considered economical, environmentally friendly, and non-toxic. X-ray diffraction patterns of the synthesized SnO2 NPs have displayed a tetragonal crystalline structure. The crystallite size of SnO2 NPs increased from 15.12 to 17.9 nm with increasing reaction temperature while decreasing from 20.68 to 17.9 nm with increasing extract concentrations. The morphology of the synthesized SnO2 NPs was investigated using high-energy transmission electron microscopy (HR-TEM). The optical energy gap was determined using the diffuse reflectance UV–vis spectra range (300–1200) nm of SnO2 NPs at different reaction temperatures and different extract concentrations. UV/Visible Spectrophotometer was used for studying the photodegradation of methylene blue dye (MB) dye. The photocatalytic degradation of MB revealed that SnO2 NPs at reaction temperature 90 °C degraded 69% of MB solution when exposed to UV illumination for 90 min while the degradation reaches 90% for 180 min of exposure. It was obvious that the degradation rate of MB was increased with the increase of reaction temperature, and the extract concentration.

Photooxidation and Virus Inactivation using TiO2(P25)–SiO2 Coated PET Film

This study chemically modified PET film surface with P25 using silicate as a binder. Different P25–binder ratios were optimized for the catalyst performance. The modified samples were analyzed by scanning electron microscopy-energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Diffuse reflectance UV-vis spectra revealed significant reductions in the band gaps of the P25 solid precursor (3.20 eV) and the surface-modified PET–1.0Si–P25 (2.77 eV) with visible light. Accordingly, under visible light conditions, catalyst activity on the film will occur. Additionally, the film’s performance was evaluated using methylene blue (MB) degradation. Pseudo-first-order-rate constants (min−1), conversion percentages, and rates (µg.mL−1.gcat−1.h−1) were determined. The coated films were evaluated for viral Phi–X 174 inactivation and tested with fluorescence and UV-C light illumination, then log (N/N0) versus t plots (N = [virus] in plaque-forming units [PFUs]/mL) were obtained. The presence of nanosilica in PET showed a high adsorption ability in both MB and Phi–X 174, whereas the best performances with fluorescent light were obtained from PET–1.0Si–P25 and PET–P25–1.0Si–SiO2 equally. A 0.2-log virus reduction was obtained after 3 h at a rate of 4×106 PFU.mL−1.gcat−1.min−1. Additionally, the use of this film for preventing transmission by direct contact with surfaces and via indoor air was considered. Using UV light, the PET–1.0Si–P25 and PET–1.0Si–P25–SiO2 samples produced a 2.5-log inactivation after 6.5 min at a rate of 9.6×106 and 8.9×106 PFU.mL−1.gcat−1.min−1, respectively. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

In-situ construction of CdS@ZIS Z-scheme heterojunction with core-shell structure: Defect engineering, enhance photocatalytic hydrogen evolution and inhibit photo-corrosion

Designing the core-shell structure and controlling defect engineering are desirable for improving the performance and stability of semiconductor photocatalysts. Herein, CdS nanorods covered with ultra-thin ZnIn2S4 nanosheets, named as CdS@ZnIn2S4-SV (CdS@ZIS-SV), was synthesized through the strategy of constructing core-shell structure and regulating vacancies. The core-shell structure can confine Cd2+ and S2− locally around CdS instead of rapidly diffusing into the solution, thereby inhibiting photo-corrosion. The abundant S vacancies can capture photogenerated electrons and promote the separation of electron-hole pairs, thereby preventing the oxidation of S2− by the holes. In addition, Z-Scheme heterojunction structure helps the effective separation of electron-hole pairs. Notably, the hydrogen production rate of CdS@ZIS-SV reached 18.06 mmol g−1 h−1, which was 16.9 and 19.6 times than pristine CdS (1.16 mmol g−1 h−1) and ZIS (0.92 mmol g−1 h−1), respectively. Photoelectric Characterization (PEC), Scanning Kelvin Probe (SKP), UV–vis diffuse reflectance spectra (UV–Vis DRS), Finite-Difference Time-Domain (FDTD) explain the electron transfer mechanism and the reason for the enhanced photocatalytic activity. This work has guiding significance for the preparation of photo-catalysts with high activity and inhibiting photo-corrosion by adjusting S vacancies.

An S-scheme heterojunction of Bi2WO6/AgIO3 nanocomposites that enhances photocatalytic degradation of Rhodamine B and antifouling properties

Bi 2 WO 6 /AgIO 3 (BWO/AIO) nanosheet composites were constructed by a two-step hydrothermal method. The structure, morphology and photoelectrochemical properties of the composites were characterized by X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (UV-DRS), transmission electron microscopy (TEM), impedance, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The constructed photocatalyst composites exhibited the best photocatalytic performance at a molar ratio of BWO/AIO-0.8. In addition, there was complete degradation of RhB by the BWO/AIO-0.8 in 180 min under illumination, and the bactericidal rates were 99.10%, 97.32% and 96.3% for P. aeruginosa , S. aureus and E. coli, respectively, in 60 min. Based on the energy band structure of the semiconductor and radical trapping experiments, the S-scheme heterojunction was associated with the enhanced photocatalytic properties.

Preparation of Ag3PO4/CoWO4 S-scheme heterojunction and study on sonocatalytic degradation of tetracycline

In this study, 0.6Ag3PO4/CoWO4 composites were synthesized by hydrothermal method. The prepared materials were systematically characterized by techniques of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption, and UV–vis diffuse reflectance spectrum (DRS). Furthermore, the sonocatalytic degradation performance of 0.6Ag3PO4/CoWO4 composites towards tetracycline (TC) was investigated under ultrasonic radiation. The results showed that, combined with potassium persulfate (K2S2O8), the 0.6Ag3PO4/CoWO4 composites achieved a high sonocatalytic degradation efficiency of 97.89 % within 10 min, which was much better than bare Ag3PO4 or CoWO4. By measuring the electrochemical properties, it was proposed that the degradation mechanism of 0.6Ag3PO4/CoWO4 is the formation of S-scheme heterojunction, which increases the separation efficiency of electron-hole pairs (e--h+) and generates more electrons and holes, thereby enhancing the degradation activity. The scavenger experiments confirmed that hole (h+) was the primary active substance in degrading TC, and free radicals (OH) and superoxide anion radical (O2–) were auxiliary active substances. The results indicated that 0.6Ag3PO4/CoWO4 nanocomposites could be used as an efficient and reliable sonocatalyst for wastewater treatment.

A one-dimensional linear samarium-containing Dawson-type phosphotungstate with photochromic behavior

A one-dimensional linear chainlike phosphotungstate based on Dawson-type [P 2 W 17 O 61 ] 10- building unit was synthesized, which exhibits reversible photochromic behavior. • A one-dimensional linear chainlike phosphotungstate was synthesized. • Constructed by monolacunary Dawson-type [α 2 -P 2 W 17 O 61 ] 10- unit. • Shows reversible photochromic property. A one-dimensional linear chainlike phosphotungstate based on Dawson-type [P 2 W 17 O 61 ] 10- building unit [H 2 N(CH 3 ) 2 ]{Sm 2 (H 2 O) 15 [Sm(H 2 O) 3 (α 2 -P 2 W 17 O 61 )]}⋅21H 2 O ( 1 ) was prepared under routine aqueous condition, which was further characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and UV–vis diffuse reflectance spectra. Single-crystal X-ray diffraction result illustrated that compound 1 displays a one-dimensional infinite chainlike architecture constructed by monolacunary Dawson-type [α 2 -P 2 W 17 O 61 ] 10- building unit and Sm 3+ connectors. The reversible photochromic property of 1 was tested under UV radiation, which was able to change from white to visible saturated blue in 2 min and recover the natural state after dark treatment for about 10 h.

Structural and optical investigations on LaGaO3 synthesis by sol–gel method along with a blue luminescence property

• LaGaO 3 perovoskite material has been successfully synthesized by a simple rout called sol gel method. • The efficiency of sol–gel methods to obtain pure phase of LaGaO3 was proved. • Raman reveals 9 bands that correspond to active optical-vibrational modes of orthorhombic symmetry that is in good agreement with XRD results. • A special emphasis is put on the photoluminescence properties of this material. Temperature-dependent PL, low-temperature analysis has been carried out. This work presents the preparation of Lanthanum Gallate peroveskite (LaGaO3) by sol–gel based Pechini method at low temperatures. The structural and optical properties of the elaborated material were investigated, by means of X-ray diffraction (XRD), Raman, UV–visible and Photoluminescence (PL) Spectroscopies. The XRD pattern showed a pure orthorhombic phase of LaGaO3 annealed at 600 °C. The orthorhombic symmetry was confirmed by Raman study. The band gap energy was estimated from UV–visible diffuse reflectance spectra to be 3.64 eV. Photoluminescence spectra of LaGaO3 showed two bands in blue region. For a complete understanding of the luminescence properties, a temperature-dependent PL analysis was studied. The temperature dependence for LaGaO3 sample revealed an S-shape behavior. The S-shape phenomenon and the variation of the FWHM values as a function of temperature were discussed. Finally, the thermal activation energy was calculated from the integrated PL intensity as a function of inverse temperature in orders to determinate the thermal stability of material.

Synthesis and Characterization of Zinc Vanadate Nanostructures for Supercapacitor Applications

A simple hydrothermal approach was used to successfully produce nanostructured Zinc vanadate (Zn3V2O8), which was calcined at 450 ℃. The structural, optical and surface morphological features of calcined Zn3V2O8 nanoparticles were investigated using a variety of analytical techniques. The produced Zn3V2O8 nanoparticles had an orthorhombic crystalline structure, with an average crystallite size of 35.14 nm, according to the X-ray diffraction pattern (XRD). Transmission electron microscopy (TEM) analysis evaluated the spherical shaped Zn3V2O8 nanoparticles. The calcined catalyst was characterized by Fourier Transform-Infrared spectroscopy (FT-IR) analysis to analyse bonding interactions between the metal fragments within the composites. The nanoparticles obtained from hydrothermal synthesis were of size 37.2 nm, and the zeta-potential of nanoparticles was found to be −25.4 mV, indicating excellent dispersion and stability. The spectrophotometer was used to analyse the UV-Vis diffuse reflectance spectra (DRS). Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the electrochemical behavior of Zn3V2O8 nanostructures. The specific capacitance value of the synthesized nanoparticles was 248.5 Fg−1. The active composite material was exploited as an electrode for the Supercapacitor application, and it revealed that synthesized Zn3V2O8 nanoparticles might lead to a possible application for future energy storage technologies.
 HIGHLIGHTS
 
 Zinc vanadate nanostructures have been prepared using easy and economical hydrothermal technique and are explored for supercapacitor application
 Electrochemical behaviour of zinc vanadate nanostructures were investigated by cyclic voltammetry, electrochemical impedance spectroscopic analysis and galvano static charge discharge analysis
 This zinc vanadate nanostructures exhibited a maximum specific capacitance of 248.5 F g−1 in the HCl electrolyte
 It clearly revealed that synthesized nanoparticles may lead to potential application for forthcoming energy storage devices
 
 GRAPHICAL ABSTRACT

Synthesis and characterization of a nanocomposite zeolite Y@metal–organic framework as photocatalyst

Zeolite Y was synthesized by hydrothermal method and then modified with carboxylic acid. Succinic anhydride was used for producing functional group on the surface of the zeolite Y. MIL-53(Al) metal–organic framework as a shell was grown over zeolite Y as a core at room temperature. The Y@MIL-53 core@shell was applied to develop a UV light active photocatalyst for degradation of Eriochrome Black-T. The materials were characterized using a range of techniques. Characterizations of samples were carried out by X-ray powder diffraction, scanning electron microscopy, Fourier transform infrared spectrometry, transmission electron microscopy, UV–Vis diffused reflectance spectra (UV–Vis DRS) and zeta potential. The highest photocatalytic activity was related to Y@MIL-53 core@shell. Degradation mechanism was attributed to electrons and holes generated in the organic ligand. Moreover, the Y@MIL-53 photocatalyst was extremely stable during five cycle test and did not demonstrate any explicit loss of photocatalytic activity during five cycle tests. The used adsorbent can be reused for adsorptive removal through simply washing. According to the experimental phenomenon, the possible mechanism of adsorption was proposed.

Facile preparation of porous g-C3N4/MoS2 heterojunction for hydrogen production under simulated sunlight

The limited surface areas and the high recombination rate of photogenerated carriers have always been two sticky problems of graphite-like carbon nitride (g-C3N4) for the application of solar hydrogen production. In this article, the porous g-C3N4 was prepared by the improved thermal polymerization method to enlarge its specific surface areas and to facilitate the transfer of internal electric charges. Then, heterojunction formed by MoS2 deposited on the g-C3N4 was built to extend the recombination time of photoproduction electrons and holes. Several techniques were used to research their structures as well as the physical and chemistry properties, such as the specific surface area analysis (BET), Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectra, transmission electron microscopy, X-ray photoelectron spectroscopy, and so on. Finally, their performance of photocatalytic hydrogen evolution was studied under simulated sunlight irradiation. As a result, the optimal ratio of melamine to urea is 1:3 for preparing the porous g-C3N4, and the g-C3N4/MoS2 has a high efficiency of photocatalytic hydrogen evolution, ca. 1913 μmol·g–1·h–1. The results showed that the composites had higher hydrogen evolution than the pure ones, which the activity increasing first, then decreasing as the contents of MoS2 growing in quantity. Furthermore, the synergy effects are elaborated by electrochemical impedance spectroscopy and Mott-Schottky analyses.

La, Zr co-doped Ag3PO4 for enhanced visible-light photocatalytic degradation of dyes and Cr(VI) photoreduction

Visible light-driven photocatalysts have attracted considerable attention as these photocatalysts can effectively utilize visible light and are cost-effective. This study reports the synthesis of silver phosphate (Ag3PO4) and 1, 3, and 5% La, Zr co-doped Ag3PO4 via precipitation method. The synthesized materials were characterized using powder X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), UV-Visible diffuse reflectance spectra (DRS), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). No impurities were observed in all the synthesized materials as shown by the XRD analysis. FTIR measurements of the synthesized materials displayed the presence of several functional groups in the synthesized materials. The band gap energy of Ag3PO4 decreases as more La and Zr were incorporated into the Ag3PO4 lattice. The SEM images of Ag3PO4 displayed tetrapod-shaped particles whereas La, Zr co-doped Ag3PO4 showed irregular particles. The photocatalytic activities of the synthesized materials were determined through photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes as well as photoreduction of Cr(VI). Results showed that 1% La, Zr co-doped Ag3PO4 exhibited superior photocatalytic properties in both photocatalytic processes when compared to Ag3PO4.

Fe doped g-C3N4 composited ZnIn2S4 promoting Cr(VI) photoreduction

30% FeCN/ZIS (30% Fe doped g-C3N4 composited ZnIn2S4) was synthesized by a simple water bath method, via in-situ growth of abundant well-dispersed ZnIn2S4 nanosheets on the Fe doped g-C3N4 surface. Experimental results showed the optimized 30% FeCN/ZIS achieved the best photoreduction of Cr(VI) performance within a wide pH range, which was 9.5 times and 700 times higher than that of pure ZnIn2S4 and 30% FeCN (Fe doped g-C3N4). This is due to the intense synergy between the Fe-Nx bond and close interface contact produces a high-speed charge transfer channel, thus significantly improving the efficiency of optical carrier separation and migration. Meanwhile, UV-vis diffuse reflection spectra and photoluminescence spectroscopy showed that iron doping significantly narrowed the bandgap of g-C3N4, preventing electron-hole pair recombination. Further, the microstructures and charge separation properties were analyzed by scanning electron microscope, Photoluminescence Spectroscopy and time-resolved photoluminescence, which revealed the structure-activity relationship of composite structure and the synergistic mechanism of each functional component. This research should provide a viable technique for creating composites with high photocatalytic activity for the treatment of chromium-containing wastewater.

Fabrication of UiO-66-NH2/Ce(HCOO)3 heterojunction with enhanced photocatalytic reduction of CO2 to CH4

The development of efficient and highly selective photocatalysts is a key point for the photocatalytic conversion of CO2. In this paper, a composite catalyst UiO-66-NH2/Ce(HCOO)3 (simplified to UNH/Ce(HCOO)3) was fabricated by one pot method with CeCO3OH as the precursor. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) characterizations results confirmed that UNH was dispersed on the surface of Ce(HCOO)3 and strongly interacted with it via Ce-N bond. The yield of CH4 on the optimal UNH/Ce(HCOO)3 catalyst reached 3 times of that on pristine UNH, up to 128.81 μmol g−1, with the CH4 selectivity of 71.9 %, and the Relectron reached 286.46 μmol g−1 h−1. The UV–vis diffuse reflection spectra and photoelectrochemical tests results confirmed that the improved photocatalytic CO2 reduction performance and high CH4 selectivity could be attributed to the formation of the type-Ⅱheterojunction of UNH/Ce(HCOO)3 with abundant Ce3+, which expanded the visible light absorption range, accelerated the separation and transfer rates of photogenerated charges, and thus efficiently promoted the multi-electron reduction reaction of CO2 to CH4. In addition, the reaction temperature affected profoundly the cycle performance of the catalyst. The results presented here illustrated the possibility for improving the stability of UNH/Ce(HCOO)3-1.80 by decreasing reaction temperature.

Impact of Sm2O3 onthe Morphological, Optical, Magnetic, and Pesticide Adsorption of Co3O4/PANI Hybrid Nanocomposites

Adsorption is one of the most favored procedures in advanced wastewater treatment. Magnetic hybrid materials have a great adsorption performance and excellent reusability in the industry. For this reason, the amazing roles of Sm2O3 doping on Co3O4/PANI hybrid nanocomposite materials were studied. Co3O4 nanoparticles were synthesized using the thermal decomposition technique where Sm2O3 doped Co3O4/ PANI hybrid nanocomposite materials were prepared via in situ oxidative polymerization. The X-ray analysis, technique results confirm the successful formation of neat Co3O4 nanoparticles with cubic phase and its presence in emeraldine phase of PANI matrix. X-ray reveals that the crystallinity of hybrid nanocomposite materials increases with increasing Sm2O3 doping ratio. HRTEM showed polycrystalline structure of Co3O4 nanoparticles and that the doped Sm2O3 was well incorporated and dispersed within the PANI matrix. The surfaces topography was studied by FESEM. UV–Vis diffuse reflectance spectrum revealed two characteristic bands of PANI that are shifted towards higher wavelengths with Sm2O3 doping ratio. The calculated indirect energy gaps were found to decrease from 2.83–2.56 eV which indicates a good response of the hybrid nanocomposite materials to the effect of the UV absorption. The magnetic properties of the investigated samples are measured by VSM. Ms was found to decrease with increasing Sm2O3, while Hc increase with Sm2O3 ratio which will hinder the domain walls motion. Adsorptive removal of chlorpyrifos could be ascribed as pseudo-second ordered and Langmuir model. The maximum adsorptive capacity was 36.9, 47.11, 63.8, and 83.03, 96.73 mg/g for PANI, Co3O4/PANI, Co3O4/PANI-2 wt% Sm2O3, Co3O4/PANI/−4 wt% Sm2O3, and Co3O4/PANI-6 wt% Sm2O3hybridnanocomposite materials, respectively.

In situ grown silver nanoparticles on tetrapod-like zinc oxide whisker for photocatalytic antibacterial in scaffolds

Tetrapod-like zinc oxide whisker (T-ZnOw) had aroused great interest in photocatalytic antibacterial due to its unique wurtzite structure and high excitonic restricting vitality. Nevertheless, the poor visible light absorption and rapid electron–hole recombination resulted in unsatisfactory reactive oxygen species (ROS) production efficiency. Herein, silver nanoparticles (AgNPs) were in situ grown on T-ZnOw to form Ag@T-ZnOw nanohybrids and then composited with poly-l-lactic acid (PLLA) powder to prepare Ag@T-ZnOw/PLLA scaffolds by selective laser sintering. On the one hand, AgNPs were expected to enhance the visible light absorption of Ag@T-ZnOw through surface plasmon resonance. On the other hand, AgNPs could act as electrons sink to accelerate photogenerated electrons transfer, thereby inhibiting electron–hole recombination. The UV–vis diffuse reflectance spectra revealed that the visible light absorption of T-ZnOw was enhanced with the introduction of AgNPs. Particularly, the band gap of Ag@T-ZnOw was decreased from 2.99 eV to 2.64 eV, implying that the electron–hole recombination time was prolonged and thereby facilitated to the generation of more ROS. Fluorescence probe measurements confirmed that ROS signal intensity of Ag@T-ZnOw/PLLA increased by 66.7% in comparison with that of T-ZnOw/PLLA, which resulted in the scaffolds exhibiting a robust antibacterial activity and thus offered a great promise for the treatment of implantation-associated infection.

Ultrasound-Assisted Hydrothermal Synthesis of SrSnO3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance for Ciprofloxacin under Visible Light

In this work, an SrSnO3/g-C3N4 heterojunction with different dosage of SrSnO3 was fabricated by an ultrasound-assisted hydrothermal approach and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectra (UV-Vis DRS), and photoluminescence spectroscopy (PL). Ciprofloxacin was adopted to assess the degradation performance, and the sample combined with 40% SrSnO3 eliminated 93% of ciprofloxacin (20 mg/L) within 3 h under visible light, which is 6.6 and 1.7 times greater than for SrSnO3 and g-C3N4, respectively. Furthermore, 85% CIP was extinguished after five cycles of a photocatalytic process. Ultimately, a possible photocatalytic mechanism was dissected.