UV Vis Diffuse Reflectance Spectra Research Articles

Construction of Bi2WO6/g-C3N4/Cu foam as 3D Z-scheme photocatalyst for photocatalytic CO2 reduction

Photocatalytic CO2 reduction to hydrocarbon fuels represents a promising solution to CO2 emission challenges. However, photocatalytic CO2 reduction systems face hurdles in practical utilization for the low efficiency of photocatalysts and challenge in catalyst immobilization. Therefore, a novel monolithic three-dimensional Z-scheme photocatalyst was synthesized by fabricating Bi2WO6/g-C3N4 heterojunction on Cu foam substrate (Bi2WO6/g-C3N4/Cu foam) via thermal polymerization and electrophoresis deposition. A series of characterization results, including X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and N2 adsorption–desorption, illustrate the crystalline properties, pore structure, and morphology of the composite photocatalyst. Consequently, Bi2WO6/g-C3N4/Cu foam achieved CO production yield of 33.84 μmol/g cat under visible light illumination for 6 h and retained 96.2 % of initial photocatalytic activity after 30 h of reaction. UV–Vis diffuse reflection spectra, photoluminescence spectra and photoelectrochemical analysis was involved to reveal the mechanism of the photocatalytic activity of composite photocatalyst.The synergistic effect of the Z-scheme mechanism and the hierarchical macroporous structure improves the light absorption, light-induced electron-hole pair separation, and charge transmission. This catalyst construction strategy provides a viable approach for facilitating practical photocatalytic CO2 reduction.

A novel iron metal organic framework-based nanocomposite for the synergistic degradation and adsorption of organic pollutants and Cr (Ⅵ) under visible light

In this work, a novel nitrogenous Fe-TPPE metal-organic-framework (MOF) with excellent visible light catalytic activity was successfully prepared, and a magnetic composite (Fe3O4@Fe-TPPE) with Z-type heterojunction structure was designed to synergistically treat organic pollutants and Cr(Ⅵ). The materials were carefully characterized by powder X-ray diffractometry, scanning electron microscope, Fourier transform infrared analysis, UV–visible diffuse reflectance spectra, X-ray photoelectron spectroscopy, thermogravimetric analysis, etc. The characterizations of photoelectric properties showed that the novel Fe-TPPE MOF exhibited strong response to visible light and Fe3O4@Fe-TPPE had even stronger response. Furthermore, the adsorption and photocatalytic degradation capabilities of Fe-TPPE and Fe3O4@Fe-TPPE, and the versatility as photocatalysts for aqueous pollutants were assessed through removal studies of the model pollutants tetracycline, rhodamine, methyl blue and Cr (VI). Additionally, the removal mechanism of the Fe3O4@Fe-TPPE for the above pollutants was explored. The high removal efficiency, fast magnetic separation, great recycling stability and minimal leak during application all demonstrate the good potential of Fe3O4@Fe-TPPE for practical and sustainable treatment of aqueous pollutants.

Construction of Zn0.5Cd0.5S/Bi4O5Br2 Heterojunction for Enhanced Photocatalytic Degradation of Tetracycline Hydrochloride

The development of efficient catalysts with visible light response for the removal of pollutants in an aqueous environment has been a hotspot in the field of photocatalysis research. A Zn0.5Cd0.5S (ZCS) nanoparticle/Bi4O5Br2 ultra-thin nanosheet heterojunction was constructed by ultrasound-assisted solvothermal method. The morphology, structure, and optoelectronic properties of the composite were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV–vis diffuse reflectance spectra. Under simulated visible light illumination, the photocatalytic performance was evaluated through degradation of tetracycline hydrochloride. Results show that the degradation effect by the optimum ZCS/Bi4O5Br2 catalyst is superior to pure materials with the kinetic constant that is 1.7 and 9.6 times higher than those of Bi4O5Br2 and ZCS, and also has better stability and reusability. Trapping experiments and electron paramagnetic resonance tests find that free radicals in the photocatalytic system are superoxide radicals and holes. This work provides a referable idea for the development of more efficient and recyclable photocatalysts.

2D Cadmium(II) Coordination Polymer Based on 2,5-Furandicarboxylate and 1,4-Bis(1H-imidazol-1-yl)butane Linkers: Synthesis, Characterization and DFT Studies

AbstractAs a result of hydrothermal synthesis of 2,5-furandicarboxylate (fdc2−), Cd(II) ion and bis(imidazole) derivative 1,4-bis(1H-imidazole-1-yl)butane (bib) ligand, a novel two-dimensional Cd(II) coordination polymer {[Cd(µ-fdc)(H2O)(µ-bib)]·H2O}n (1) was synthesized. According to the results of single crystal X-ray diffraction analysis, the complex was crystallized in the monoclinic system and in the P21/n space group. In addition, the thermal, luminescence and optical properties of the complex were investigated. The complex emits a maximum at 509 nm and also shows semi-conductor properties according to the solid-state UV–Vis diffuse reflection spectra results. To determine chemical structure, vibrational properties and some chemical properties of complex, theoretical calculations were carried out. All theoretical computations were performed using the DFT method at the B3LYP/LanL2DZ level of theory. The obtained experimental results were in good agreement with theoretical results. To calculate HOMO–LUMO energy values, which provided insights into the material's electronic properties, DFT calculations were used. Detailed information about the local and global chemical activity, as well as the electrophilic and nucleophilic nature of the complex, were also obtained.

Crystal structure, optical properties, Hirshfeld surface analysis and antibacterial activity of a new organic-inorganic metal halide: 4-nitrobenzyl-4-methylpyridinium tetrachlorocobaltate(II)

This paper presented the synthesis, composition analysis, and structural characterization of a new organo-inorganic metal halide, 4-nitrobenzyl-4-methylpyridinium tetrachlorocobaltate(II) [4NO2Bz-4-MePy]2[CoCl4](1). The single-crystal X-ray diffraction analysis displayed that the compound crystallized in the monoclinic space group P21/c, consisting of two [4NO2Bz-4-MePy]+ cations and a [CoCl4]2− anion. The energy gap between the HOMO and LUMO orbitals, the polarizability, and the first hyperpolarizability were carried out based on the DFT calculation. The HOMO-LUMO energy gap and UV-visible diffuse reflectance spectrum illustrated the charge transfer interactions between the [CoCl4]2− anions and the [4NO2Bz-4-MePy]+ cations. In addition, the low band gap values (1.64 eV for the Tauc formula, 1.62 eV for the truncated line method, and 2.73 eV for the calculated value) indicated that the crystal was appropriate for optical applications. The first hyperpolarizability (βtot) was 342 times higher than that of standard KDP crystal (βKDP = 6.85 × 10−31 esu), suggesting that crystal 1 was a premium material for NLO applications. The scanning electron microscopy and energy dispersive spectrometer determined the morphology and elemental distribution of the crystal. Hirshfeld surface analysis was performed to quantify the contributions of the different intermolecular interactions. The result of antimicrobial experiments displayed that the compound had excellent antimicrobial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Crystal structure, electronic structure and thermal stability of new phosphate Sr2In(PO4)(P2O7)

Searching for new phosphates is of special significance to enrich the basic database of the structure and properties for developing inorganic materials. Here, we present a new phosphate Sr2In(PO4)(P2O7) which crystallizes to a monoclinic cell (S.G. P21/c), with the lattice parameters of a = 6.5832(3) Å, b = 6.8984(3) Å, c = 19.813(1) Å, β=99.562(1)°, V = 887.3(1) Å3, and Z = 2. The three-dimensional frame of this structure is made of InO6, PO4, P2O7, SrO8, and SrO9 units. The co-existence of P2O7 and PO4 was confirmed by IR spectra assignment. The VB maximum and CB minimum of Sr2In(PO4)(P2O7) are dominated by In-s and O-p state, respectively. Combining the calculated electronic structure with measured UV–Vis diffuse reflectance spectrum, this phosphate shows a wide indirect energy band-gap. DTA indicates that its melt point is about 1245 °C. The large band gap and high thermal stability would be catering for the material requirement in futural optical or other functional application fields.

Sol-Gel technique, characterization and photocatalytic degradation activity of Manganese doped ZnO nanoparticles

Photocatalysis using semiconductor metal oxide stands out as a highly effective and efficient method for eliminating organic pollutants from wastewater. This study aims to assess the photocatalytic capabilities of Mn doped ZnO nanocomposites in degrading methylene blue (MB) dye under ultra-violet light exposure. This study details the synthesis of ZnO photocatalysts through a straightforward one-step sol-gel method, incorporating varying levels of Mn-doping (0%, 2% & 4%). The structural and optical attributes were examined using techniques such as powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and UV-Vis diffuse reflectance spectra. X-ray diffraction analyses verified the presence of a hexagonal wurtzite crystal structure in all synthesized samples, exhibiting a high degree of crystallinity. In addition, an investigation into the impact of Mn impurities on the photocatalytic performance of ZnO catalysts was conducted in the context of methylene blue (MB) degradation. The experimental findings revealed that the Mn doped ZnO nanoparticles produced exhibited significantly superior photocatalytic performance compared to pure ZnO when used in breaking down methylene blue under UV-light exposure. This study proposes that these Mn doped ZnO could serve as a highly effective photocatalyst for treating water contaminated with certain chemically persistent synthetic organic dyes. The improved photocatalytic capabilities of ZnO nanostructures doped with Mn were ascribed to the synergistic impact of increased surface area in ZnO nanosphere and enhanced efficiency in charge separation resulting from optimized Mn doping. A potential explanation for the heightened photocatalytic performance of Mn-doped ZnO nanostructures is proposed tentatively.

Facile construction of MoS2 decorated CdS hybrid heterojunction with enhanced hydrogen generation performance

Promoting the charge separation to improve photocatalytic performance of semiconductor photocatalysts is very important in the field of artificial photosynthesis. Here, a novel MoS2/CdS 2D–2D ultrathin nanosheet heterostructure was fabricated via a one-pot solvothermal route. The obtained 2D–2D MoS2/CdS nanojunction has not only provided large contact areas, but also shortened the charge transport distance, resulting in significantly enhanced photocatalytic H2 evolution property. The composites that were synthesized were examined using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), UV-vis diffuse reflectance spectra (DRS), Photoluminescence (PL) and X-ray photoelectron spectra (XPS) analysis. By optimizing the 2D MoS2 amounts in the heterojunction, the 5 wt.% 2D/2D MoS2/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 4449 μmolh−1g−1 under visible light irradiation in the presence of lactic acid as the sacrificial reagent, which was 6 times higher than that of pristine 2D CdS. Based on the photoelectrochemical and photoluminescence spectra tests, it could be deduced that the charge separation and transfer of 2D/2D MoS2/CdS heterojunction was tremendously improved, and the recombination of photoinduced electron-hole pairs was effectively impeded. Moreover, the 2D MoS2 was used as a cocatalyst to provide the abundant active sites and lower the overpotential for H2 generation reaction. The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H2O into H2.

Photocatalytic oxidation degradability of ammonia–nitrogen and Ni/Co ammonia complexes in ternary precursor wastewater by constructing MoS2/g-C3N4 heterojunction: Performance and mechanism

In this study, MoS2/g-C3N4 heterojunction photocatalysts were fabricated in order to treat ammonia–nitrogen wastewater resulting from the production of ternary cathode material precursors used in the manufacture of lithium-ion batteries. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption–desorption test, UV–Vis diffuse reflectance spectra (UV–Vis DRS), Fourier-transform infrared spectroscopy (FT-IR Nicolet 6700), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The catalytic efficiency of the catalysts on ammonia–nitrogen and Ni/Co ammonia complexes in the wastewater was investigated by varying MoS2 doping, catalyst dose, adsorption duration, and photocatalysis duration. The results showed 2.0 g/L of MoS2/g-C3N4-1 wt% (photocatalyst with a content of 1 wt% MoS2) has the best photocatalytic efficiency. A degradation efficiency of 87.52 % for ammonia–nitrogen, 98.34 % for nickel and 97.80 % for cobalt was reached after one hour of dark adsorption and four hours of illumination. EDS and XPS analysis revealed that Ni2+/Ni3+ and Co2+/Co3+ were adsorbed from the solution onto the catalyst surface, and that NH4+/NH3 was converted into NO3− and N2.

Synthesis, crystal structure, spectroscopic properties, thermal behavior and DFT studies of a new organic-inorganic hybrid [4FBzTPP]2[CoBr4]

A new organic-inorganic hybrid [4FBzTPP]2[CoBr4](1) (4FBzTPP = 4-fluorobenzyltriphenylphosphonium) was synthesized and characterized by X-ray diffraction, DTA-TG measurement, FT-IR and Raman spectroscopies, Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and UV–vis diffuse reflectance spectrum. [4FBzTPP]2[CoBr4] crystallized in monoclinic system with P21/c space group, consisting of two [4FBzTPP]+ cations and one distorted tetrahedral [CoBr4]2− anion. Powder X-ray diffraction analysis confirmed the bulk phase purity and homogeneity of the material. The UV–vis-DRS result indicated that the energy gap value of the electron transition was 1.60 eV, which was quite distant from the calculated value of 1.64 eV. The material showed fluorescent emission at 389 nm, 414 nm, 448 nm, and 495 nm under the excitation of UV light at 380 nm. Theoretical calculations were performed using the density functional theory method to derive the dipole moment and first hyperpolarizability of the as-synthesized molecule. The first hyperpolarizability value (βtot) was more than 11,600 times higher than those of standard KDP crystals, indicating that [4FBzTPP]2[CoBr4] was an excellent material for applications.

Synthesis and Spectroscopic Investigations of Sm3+ Activated ZrO2 and Na2ZrO3 as Warm Light Phosphors.

In this work, we investigate how the structural and optical characteristics of ZrO2 and Na2ZrO3 are influenced by Sm3+ ion doping. Urea-assisted combustion approach is employed by varying the molar concentration of Sm3+ ions in both the host lattices. XRD pattern revealed the monoclinic crystal system for both samples. XPS investigation has been examined to acquire the chemical information of the samples. FESEM is used to identify the morphology of the samples. The optimum molar concentrations of Sm3+ doped ZrO2 and Na2ZrO3 phosphors, as per photoluminescence (PL) findings, are 1.5mol% and 2mol%, respectively. CIE coordinates of ZrO2:Sm3+ and Na2ZrO3:Sm3+ are found to be (x = 0.59, y = 0.41) and (x = 0.61, y = 0.39) that corresponds to the amber region of color gamut. The optical bandgap for the synthesized samples is estimated using the UV-Vis diffuse reflectance spectra and the obtained values for the optimal concentration of dopant (Sm3+) in the ZrO2 and Na2ZrO3 samples are 4.61 and 4.94eV, respectively. The findings of the study reveal that the synthesized phosphors may be utilized as warm light phosphors and be a promising candidate for amber light-emitting diodes (LEDs).

Enhanced photocatalytic reduction of Cr (VI) using Ag@AgCl/RGO/CuO nanocomposite under visible light

This study investigated the photocatalytic activity of three nanocomposites, namely Ag@AgCl, Ag@AgCl/RGO, and Ag@AgCl/RGO/CuO, by examining their ability to reduce Cr (VI) using visible light irradiation. The photocatalytic samples were characterized using various methods, including X-ray diffraction, Fourier transform infrared spectroscopy, field emission-scanning electron microscopy, Raman spectroscopy, UV–Vis diffuse reflectance spectra, and photoluminescence spectroscopy. Our findings showed that the incorporation of CuO and RGO co-catalysts significantly improved the photocatalytic reduction of Cr (VI) in the plasmonic Ag-AgCl sample. Among the three samples, the Ag@AgCl/RGO/CuO nanocomposite demonstrated the highest efficiency in reducing Cr (VI) to Cr (III) using visible light with a 98 % reduction of Cr(VI) within 45 min. The improved efficiency of the Ag@AgCl/RGO/CuO photocatalyst could be attributed to its superior ability to absorb visible light and reduce the rate of electron-hole recombination. The Ag@AgCl/RGO/CuO also showed a reaction rate constant of 0.086 min−1, which was approximately 17 times faster than that of Ag@AgCl.

Parameter relationship and product characteristics analysis of heavy-metal hazardous wastes vitrification under the combination of data science and experiment

Heavy-metal hazardous wastes (HMHW) have a large emission, high toxicity and strong resource properties. Its proper disposal and resource utilization is a key challenge. High-temperature melt vitrification technology is an effective solution to realize the detoxification and resource utilization of HMHW. This paper summarizes and analyzes the control parameters of the existing vitrification treatment of HMHW. The phase transformation process of temperature, slag content, and CAS ratio (CaO-Al2O3-SiO2) in the vitrification treatment of zinc leaching residue (ZLR) was investigated around the vitreous content. The common evolution characteristics of the formed vitrification products in infrared spectrum, UV–vis diffuse reflection spectrum, and microstructures were revealed. The idea of using the maximum UV–vis absorption intensity to qualitatively determine the vitreous content of the products is proposed. Moreover, the correlation between experimental parameters and vitreous content was quantified by combining the data science method, and the mapping of the whole process of ZLR vitrification treatment was constructed. This work provides reliable parameter guidance and method induction for the vitrification treatment of HMHW, especially for wastes with less glassy matrix such as Ca and Si.

Characterization and the Effect of Different Parameters on Photocatalytic Activity of Montmorillonite/TiO2 Nanocomposite under UVC Irradiation

This study aimed to modify montmorillonite (MMT) with titanium dioxide (TiO2) by wet stirring method combined with ultrasonic to form MMT/TiO2 nanocomposite and used as a photocatalyst in the removal of organic dye rhodamine B (RhB). The characteristics of the synthesized samples were analyzed by methods such as energy-dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis diffuse reflectance spectra (UV-Vis DRS). The degradation of RhB was carried out for 210 min under UVC irradiation, and the decolorization efficiency of RhB was evaluated by UV-vis spectroscopy. The results show that the TiO2 anatase nanoparticles are randomly distributed on the surface or the space between the MMT sheets to form a house-of-card structure. After 210 min of exposure under a UVC light source, the decolorization efficiency reached 91.5% for the solution with pH = 6.8, photocatalyst content 0.1 g/L, initial concentration RhB 10 mg/L, and UVC power 15 W. Liquid chromatography–mass spectrometry (LCMS) identified the degradation intermediates that MMT/TiO2 successfully cleaved the chromophore structure and formed more minor broken-ring by-products. The influence of operating parameters on RhB removal efficiency, including solution pH, photocatalyst content, initial dye concentration, inorganic, and organic scavengers, was studied. In addition, the kinetic modeling study shows that the RhB photodegradation reaction is consistent with the Langmuir-Hinshelwood first-order kinetic model.

Degradation of 2,4-dinitrotoluene in aqueous solution by dielectric barrier discharge plasma combined with Fe–RGO–BiVO4 nanocomposite

2,4-Dinitrotoluene (2,4-DNT) as a priority and hazardous pollutant, is widely used in industrial and military activities. In this study the synergistic effect of Fe–RGO–BiVO4 nanocomposite in a non-thermal dielectric barrier discharge plasma reactor (NTP-DBD) for degrading 2,4-DNT was evaluated. Preparation of the Fe–RGO–BiVO4 nanocomposite was done by a stepwise chemical method depositing Fe and reduced graphene oxide (RGO) on BiVO4. Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), UV–vis diffuse reflectance spectra (DRS), and energy-dispersive X-ray spectroscopy mapping (EDS-mapping) validated the satisfactory synthesis of Fe–RGO–BiVO4. To find the optimal conditions and to determine the interaction of model parameters, a central composite design (RSM-CCD) had been employed. 2,4 DNT can be completely degraded at: initial 2,4-DNT concentration of 40 mg L−1, Fe–RGO–BiVO4 dosage of 0.75 g L−1, applied voltage of 21kV, reaction time of 30 min and pH equal to 7, while the single plasma process reached a degradation efficiency of 67%. The removal efficiency of chemical oxygen demand (COD) and total organic carbon (TOC) were 90.62% and 88.02% at 30 min contact time, respectively. Results also indicated that average oxidation state (AOS) and carbon oxidation state (COS) were enhanced in the catalytic NTP-DBD process, which demonstrate the effectiveness of proposed process for facilitating biodegradability of 2,4-DNT.

Emerald eco-synthesis: harnessing oleander for green silver nanoparticle production and advancing photocatalytic MB degradation with TiO2&CuO nanocomposite

The tertiary composite of TiO2/CuO @ Ag (TCA) were synthesized by the solid state method using different ratios of TiO2/CuO NCs and Ag NPs. The structural, morphological, and optical properties of nanocomposites were analyzed by scanning electron microscope, Transmission electron microscope, X-ray diffraction, Fourier transform infrared spectra, UV–Vis diffuse reflectance spectra (UV–Vis/DRS) and photoluminescence spectrophotometry. The results showed enhanced activity of TCA hybrid nano crystals in oxidizing MB in water under visible light irradiation compared to pure TiO2. The photocatalytic performance TCA samples increased with suitable Ag content. The results show that the photo degradation efficiency of the TiO2 compound improved from 13 to 85% in the presence of TiO2–CuO and to 98.87% in the presence of Ag containing TiO2–CuO, which is 7.6 times higher than that of TiO2. Optical characterization results show enhanced nanocomposite absorption in the visible region with long lifetimes between e/h+ at optimal TiO2–CuO/Ag (TCA2) ratio. Reusable experiments indicated that the prepared TCA NC photo catalysts were stable during MB photo degradation and had practical applications for environmental remediation.

Microwave-assisted synthesis of SnO2:ZnO nanocomposites for photocatalytic, antimicrobial and electrochemical urea detection applications

In this work, we have synthesized SnO2:ZnO nanocomposites (0.25, 0.5, 0.75, and 1 M ZnO) by employing an efficient microwave-assisted synthesis method. The synthesized nanocomposite's structural, morphological, and optical characteristics are examined using different physicochemical techniques. The X-ray diffraction patterns revealed that the SnO2 and ZnO nanoparticles crystallize in tetragonal and hexagonal crystal systems, respectively. This observation is further substantiated by the results obtained in the Raman analysis. The Field Emission Scanning Electron Microscope study of SnO2:ZnO nanocomposites (NCs) reveals a few rod-shaped nanoparticles as well as big, irregularly shaped particles of reduced size. Additionally, the absorption edge of diffuse reflectance UV–visible spectra exhibits a red shift, and the band gap value of SnO2:ZnO NCs at equal proportion is determined to be 3.3 eV. In the presence of hydrogen peroxide (H2O2), the photocatalytic degradation efficiency of the synthesized nanocomposites is investigated for different dyes. With a degradation efficiency of 98 %, the nanocomposites tend to be more reactive towards crystal violet dye (20 ppm) than the other dyes while adding 20 mg of synthesized SnO2:ZnO NCs in equal proportions. The impact of pH and reactive oxygen species involved in the degradation process is also tested. SnO2:ZnO material showed nearly similar degradation efficiency even after six recycles. The study of electrochemical detection of urea employing SnO2:ZnO NCs showed a two-fold increase in peak current value with a detection limit between 0.05 and 4 mM urea. In addition, Escherichia coli and Bacillus subtilis strains were used to test the nanocomposite's antibacterial capabilities, which showed promise as potential antimicrobial agents.

Cobalt catalyzed ethane dehydrogenation to ethylene with CO2: Relationships between cobalt species and reaction pathways

TiO2, ZrO2 and a series of TiO2-ZrO2 (TxZ1, x means the atomic ratio of Ti/Zr = 10, 5, 1, 0.2 and 0.1) composite oxide supports were prepared through co-precipitation, and then 3 wt% Co was loaded through wetness impregnation methods. The obtained 3 wt% Co/TiO2 (3CT), 3 wt% Co/ZrO2 (3CZ) and 3 wt% Co/TxZ1 (3CTxZ1) catalysts were evaluated for the oxidative ethane dehydrogenation reaction with CO2 (CO2-ODHE) as a soft oxidant. 3CT1Z1 catalyst exhibits excellent catalytic properties, with C2H4 yield, C2H6 conversion and CO2 conversion about 24.5 %, 33.8 % and 18.0 % at 650 °C, respectively. X-Ray Diffraction (XRD), in-situ Raman, UV–vis diffuse reflectance spectra (UV–vis DRS), H2 temperature-programmed reduction (H2-TPR), Electron paramagnetic resonance (EPR) and quasi in-situ X-ray Photoelectron Spectroscopy (XPS) have been utilized to thoroughly characterize the investigated catalysts. The results revealed that 3CT1Z1 produced TiZrO4 solid solution with more metal defect sites and oxygen vacancies (Ov), promoting the formation of Co2+-TiZrO4 structure. Furthermore, the presence of Ov and Ti3+can facilitate the high dispersion and stabilization of Co2+, as well as suppressing the severe reduction of Co2+, leading to superior ethane oxidative dehydrogenation activity. Besides, less Co0 is beneficial to ODHE reaction, because of its promotion effects for reverse water gas shift reaction; however, more Co0 results in dry reforming reaction (DRE). This work will shed new lights for the design and preparation of highly efficient catalysts for ethylene production.

Activation of Z-scheme heterojunction of peroxymonosulfate for augmented visible-light-induced photocatalytic decomposition of tetracycline and enhanced antimicrobial efficacy with O-doped g-C3N4@Co3O4

The widespread use of graphitic carbon nitride (CN) for environmental pollutant removal has been hampered by intrinsic limitations, notably facile electron-hole recombination and a limited surface area. This work successfully synthesized OCN/Co3O4 composite materials. Furthermore, the implementation of a peroxymonosulfate (PMS) reaction system remarkably enhanced the material’s capability to degrade Escherichia coli (E. coli) and tetracycline hydrochloride (TC). Compared with CN, the composite material possessed a notably larger specific surface area, affording it a profusion of reactive sites. Additionally, the replacement of carbon atoms with oxygen atoms in the original CN structure profoundly altered its electronic configuration. The characterization through UV–Vis diffuse reflectance spectra, photoluminescence, transient photocurrent responses, and electrochemical impedance spectroscopy also confirmed the excellent optical and electrochemical attributes of OCN/Co3O4. Experimental results illustrated OCN/Co3O4/Vis/PMS completely degraded E. coli at an initial concentration of 1 × 107 CFU mL−1 within 1 h and reduced TC with the adding concentration of 10 mg/L by 99.2% in only 20 min. An analysis was conducted on reactive oxygen species (ROS) using electron paramagnetic resonance spectroscopy and radical quenching experiments. The test results demonstrated the generation of ROS including •O2−, •OH, h+, and SO4•− within the reaction system. This work explored the degradation mechanism in the OCN/Co3O4/Vis/PMS system, providing innovative insights for the design of eco-friendly, efficient catalysts as well as the enhancement of TC and E. coli degradation through the synergistic activation of photocatalytic PMS.

Highly efficient ZnFe2O4 decorated g-C3N4/GO with biomedical and photocatalytic activities

In this work, a novel magnetic composite was synthesized using graphene oxide (GO), graphitic carbon nitride(g-C3N4), and zinc ferrite (ZnFe2O4) for photocatalytic and biomedical functions. The synthesized nanocomposite (g-C3N4/GO/ZnFe2O4) was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX), UV–Vis diffuse reflectance spectra (DRS), vibrating sample magnetometer (VSM), Brunner-Emmett-Teller theory (BET), and photoluminescence (PL) techniques. Decorating g-C3N4 and GO by ZnFe2O4 as a multi-component photocatalyst with a simple and cost-effective method in our work shows high efficiency, antibacterial, and anticancer activity. The outcome of using the nanocomposite as a novel heterojunction structure, in comparison to other individual photocatalysts, has shown great activity in degrading methylene blue (MB) due to the formation of electron-hole pairs. GO improved the photocatalyst adsorption capacity and life of charge carriers, facilitating the transfer of electrons. Also, ZnFe2O4 increased the separate charges and reusability process by making heterojunction structures. The dye degradation process attained 98 % promising efficiency in only 60 min and just 3.7 % degradation after 30 min in dark conditions. The Plausible mechanism shows the Z-scheme route. Also, practical factors such as pH, concentration, dosage, and scavenger were obtained, and the optimal values were 10, 20 mg/L, 0.3 g/L, and EDTA (Ethylenediamine tetraacetic acid), respectively. The reusability of nanocomposite was also analyzed in 6 cycles. Finally, the nanocomposite made the area of inhibition on Pseudomonas aeruginosa (Gram-negative bacteria) and Bacillus cereus (Gram-positive bacteria) about 18 ± 0.5 mm and 14 ± 0.2 mm, respectively. Also, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium assay was examined. The MTT assay for breast cancer cell lines showed the survival percentage of cells is between 99.2 % and 61.4 %, so it can be applied as a carrier.