ESR Techniques Research Articles

Tailoring of silica nanoarchitecture to optimize Cu(2−x)S based image-guided chemodynamic therapy agent

The present work introduces various synthetic and post-synthetic modes of co-doping of oleate-oleylamine-stabilized Cu(2−x)S cores with red emitting [Ru(dipy)3]2+ into amino-modified silica nanoparticles (SNs) with the aim to combine chemodynamic therapy (CDT) with cellular uptake and imaging functions. Thereto, the ROS generation by the Cu(2−x)S embedded into the SNs was manifested by the spin trap facilitated ESR technique and correlated with such parameters as size of the embedded cores, content and oxidation extent of copper ions. The parameters were varied through the different extent of an oxidative degradation of the embedded Cu(2−x)S cores by their post-treating with histidine, polyethylenimine and citrate-stabilized carbon dots (CDs). The treating by CDs was chosen as the optimal post-synthetic modification of the composite SNs due to combination of CDT with high stability to aggregation. The green or dual green-red emission of the CD-treated composite SNs visualizes their cell internalization and intracellular localization by means of fluorescence and confocal microscopy methods. Correlation of cytotoxicity data of the differently treated composite SNs with their ability to ROS generation and the intracellular localization highlight the enhanced cell internalization and nuclear confinement of the CD-treated composite SNs as the factor enhancing their cytotoxicity in greater extent than the CDT function.

Anticancer potential of hexamolybdenum clusters [{Mo6I8}(L)6]2− (L = CF3COO− and C6F5COO−) incorporated into different nanoparticulate forms

The work for the first time highlights the specific nanoparticulate form of hexamolybdenum cluster complexes [{Mo6I8}(L)6]2− with L = CF3COO− and C6F5COO− (Mo6) exhibiting high anticancer potential in the irradiation-free conditions. The diverse nanoparticulate forms developed from the Mo6-units include self-aggregated (Bu4N)2[{Mo6I8}(L)6 (Mo6-aggregates) and those deposited onto the specifically decorated silica nanoparticles (SNs). The chemical and colloid stabilities of the as prepared nanoparticles reveal both Mo6-aggregates and those deposited onto the preliminary hydrophilized by polyethyleneimine (PEI) SNs (Mo6-PEI-SNs) as optimal candidates for biomedical applications. High photodynamic activities of Mo6-aggregates and Mo6-PEI-SNs revealed by the spin trap facilitated ESR technique along with the efficient irradiation-induced cytotoxic effects of both nanoparticulate forms indicate their great potential in photodynamic therapy. However, “dark” cytotoxicity measurements for M−HeLa cancer and Chang Liver normal cell lines revealed significant specific anticancer effect of Mo6-aggregates, but the insignificant one of Mo6-PEI-SNs. Quantitative LysoTracker-facilitated colocalization analysis in lysosomal compartments highlighted the highest lysosomal localization of Mo6-aggregates for L = CF3COO−, to a lesser degree for L = C6F5COO−, for Mo6-PEI-SNs being the lowest. The great anticancer effect of the Mo6-aggregates correlates with their highest localization in lysosomal compartment followed by the enhanced aggregation, in turn, derived from the hydrophobic apical ligands.

(α-Fe2O3)1-x(V2O5)x catalysts with enhanced acid-base property for the highly active and ortho-selective methylation of phenol

A series of highly active and ortho-position selective catalysts based on (α-Fe2O3)1-x(V2O5)x catalysts were proposed for the C-methylation of phenol with methanol. The (α-Fe2O3)1-x(V2O5)x catalysts were synthesized by coprecipitation method of Fe and V elements and microwave drying. The chemical composition, material structure, acid-base properties, and structure-activity relationship of (α-Fe2O3)1-x(V2O5)x catalysts were systematically analyzed by the techniques of XRD, XPS, TEM, N2 adsorption-desorption, Raman, UV-Vis, ESR, NH3/CO2-TPD and Pyridine-IR. The (α-Fe2O3)1-x(V2O5)x catalysts have the double advantages of high activity and high stability for the methylation of phenol due to the high BET surface area, large total pore volume, dispersive active sites and enhanced acid-base property. o-cresol and 2,6-xylenol were the main products, and nearly 100% selectivity to the ortho-position of phenol and 90% selectivity to o-cresol were obtained. Furthermore, the (α-Fe2O3)1-x(V2O5)x catalysts possess long lifetime over 2500 h and high activity at a weight hourly space velocity of 1.6 h−1 compared with the microwave-dried α-Fe2O3 catalyst. The doping of vanadium improves the activity and stability of α-Fe2O3 catalyst, which attributes to the modification of catalyst structure, especially the improvement of acid-base centers and oxygen vacancy. Recently the (α-Fe2O3)1-x(V2O5)x catalysts have been stably and efficiently applied in industry for the methylation of phenol.

Direct dual-Z-scheme PANI/Ag2O/Cu2O heterojunction with broad absorption range for photocatalytic degradation of methylene blue

The PANI/Ag2O/Cu2O (PAC) direct dual-Z-scheme heterojunction was synthesized by ultrasonic-assisted wet impregnation method. The heterojunction utilizes broad spectrum form UV, visible to NIR region. The structural characterization and chemical composition was explored by series of instrumental techniques. A significant photodegradation rate of 275 × 10−4 min−1 against methylene blue (MB) were observed on addition of H2O2 at pH 8. H2O2 addition intensify the •OH radicals generation that photodegraded nearly 98% of MB in 40 min. Further, trapping experiment and ESR technique validate the active role of •OH, •O2− radicals and holes during photocatalytic process. Several critical factors governing the rate of photodegradation such as pH, concentration H2O2, MB and photocatalyst were also analysed. The degradation mechanism and the intermediate formed were established by performing HPLC and LCMS analysis. Lastly, the direction of charge migration, slower rate of recombination, and effective separation of charge carrier were explicit by XPS analysis and electrochemical study. Based on the obtained results, work function of independent photocatalysts and the alignment of energy bands, a plausible direct dual-Z-scheme charge migration were proposed.

Mixed ligand transition metal(II) complexes: Characterization, spectral, electrochemical studies, molecular docking and bacteriological application

Mixed ligand complexes of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) with N,N'-1,4-phenylene (2-hyboxynaphthaliden imine) (H2L) as primary ligand and 4-aminoantipyrine (4-AAp) as secondary ligand have been prepared. The newly formed complexes were characterized using elemental analysis, magnetic susceptibility, molar conductance, 1H NMR, UV–Vis., FTIR, X-ray diffraction, mass, thermal analysis and ESR techniques. The elemental analysis, data reveal the formation of [2:1:2] [M: H2L: 4-AAP] complexes. The mode of bonding between Cu(II), Ni(II), Co(Il), Mn(II) and Cd(II) and ligands has been studied by IR spectrophotometry. Electronic absorption spectra and magnetic moment measurements of the mixed-ligand complexes suggest a distorted octahedral geometry around the central metal ion and the anions X− are in the axial positions, for all compounds. The ligands are found to behave in a neutral bidentate manner, through nitrogen atom and oxygen atom of carbonyl group (secondary ligand), whereas H2L (primary ligand) coordinated through nitrogen and OH group as a neutral ligand. FT-IR spectral data shows that the ligand acted as bis-bidentate coordination through ON–NO donor system. The XRD patterns of the ligand and its mixed ligand complexes showed the polycrystalline natures. The ligand and its mixed complexes were studied for their microbial activity against some bacteria and fungi. The ligand in comparison to its mixed ligand complexes (1-5) was screened for their antibacterial activity against Klebsiella pneumoniae, Escherichia coli, Pseudomonas sp., Staphylococcus aureus and Bacillus cereus. Antifungal activities of ligand in comparison to its mixed ligand complexes (1-5) were determined against Fusarium oxysporum, Aspergillus niger and Candida albicans. It was found that the mixed ligand complex (5) is more active than other mixed ligand complexes and penicillin G against Bacillus cereus, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas sp. The mixed ligand complex (5) is more active than the ligand and other mixed ligand complexes and miconazole against Aspergillus niger. The inhibition efficiency of the prepared ligand (H2L) against the corrosion of P355 carbon steel in HCl (2 M) solution was determined by various electrochemical methods are found to be in reasonable agreement. The morphology of protected P355 carbon steel was test by energy dispersive X-ray and scanning electron microscope (EDX–SEM).

Effect of heat treatment on the photocatalytic activity of α-Fe2O3 nanoparticles: towards diclofenac elimination.

α-Fe2O3 nanoparticles were synthesized via a straightforward method. XRD, FTIR, SEM, ESR, and DRS techniques investigated the influence of various calcination temperatures on the crystal structure, optical, and photocatalytic properties of the samples. The obtained results demonstrated that the average crystallite size increased with the increase in the calcination temperature. Measured and computed optical properties were in accordance and the bandgap energy decreased with the increase in the calcination temperature. The highest photocatalytic degradation efficiency for diclofenac (DCF) was obtained with the sample calcinated at 300 °C (96%). The photocatalytic process occurs because of the presence of OH• radicals. The addition of H2O2 led to the inhibition of OH• radicals that H2O2 scavenged.

Micro-structural, dielectrical and magnetic properties of Cu2+ substituted Ni0.7Mn0.3-xCuxFe2O4 (x = 0.0, 0.05, 0.1, 0.15 and 0.2) nano-ferrites

The nano-ferrites with chemical formula Ni0.7Mn0.3-xCuxFe2O4 having × between 0.0 and 0.2 were prepared by sol-gel auto-combustion process. The XRD pattern presents quite a good evidence for the formation of ferrite spinel phase in all the prepared samples. The broad lines indicate that the particles are of nano-size. The SEM studies reveal about the uniformity and crystallinity of the materials and also the spherical shape of the grains. Rise in copper density leads to fall in dielectric constant (εr) due to the relocation of Fe3+ from B-position to A-position. The dielectric loss (tan δ) maxima location swings towards the lower frequency as composition of dopant rises. The saturation magnetization and net magnetic moment decline with rise in Cu composition. The ESR technique ropes the subsistence of non collinear magnetic structure as predicted by VSM measurements.

Molecular Optimization for Nuclear Spin State Control via a Single Electron Spin Qubit by Optimal Microwave Pulses: Quantum Control of Molecular Spin Qubits

Quantum state control is one of the most important concepts in advanced quantum technology, emerging quantum cybernetics and related fields. Molecular open shell entities can be a testing ground for implementing quantum control technology enabling us to manipulate molecular spin quantum bits (molecular spin qubits). In well-designed molecular spins consisting of unpaired electron and nuclear spins, the electrons and nuclear spins can be bus and client qubits, respectively. Full control of molecular spin qubits, in which client spins interact via hyperfine coupling, is a key issue for implementing quantum computers (QCs). In solid-state QCs, there are two approaches to the control of nuclear client qubits, namely, direct control of nuclear spins by radio-wave (RF) pulses and indirect control via hyperfine interactions by microwave pulses applied to electron spin qubits. Although the latter is less popular in the literature, the indirectness has advantage of greatly reducing unnecessary interactions between a qubit system and its environment. In this work, we investigate molecular spin optimization to find optimal experimental conditions which can afford to achieve the high fidelity of quantum gates by the indirect control scheme. In the present quantum systems, one electron is directly controlled by pulsed ESR techniques without manipulating individual hyperfine resonance, but the states of two nuclear client spins are indirectly steered via hyperfine interactions. Single crystals of potassium hydrogen maleate (KHM) radical and 13C-labeled malonyl radical are chosen as typical molecular spin qubits which exemplify the importance of the symmetry of hyperfine tensors and their collinear properties. We have found that both the non-collinearity of the principal axes of hyperfine coupling tensors and the non-distinguishability/non-equivalency between nuclear spins are key issues which extremely reduce the gate fidelity.

Mechanisms for Cr(VI) reduction by alcohols over clay edges: Reactive differences between ethanol and ethanediol, and selective conversions to Cr(IV), Cr(III) and Cr(II) species

Catalytic reduction by alcohols over clay minerals works efficiently under a wide range of pH and represents an emerging approach to control Cr(VI) contamination. Herein, mechanisms for Cr(VI) adsorption and reduction at clay edges are addressed by dispersion-corrected periodic DFT calculations, considering different active sites, and types (monohydric and polyhydric) and coverage of alcohols. Cr(VI) adsorbs favorably at clay edges, forming direct bonds and strong H-bonds. Mechanisms for Cr(VI) reduction by alcohols are largely determined by π-conjugation development, and efficient conversion conduces to Cr(VI) removal. Cr(II), Cr(III) and Cr(IV) are useful for different purposes, and high selectivity towards these products is realized through rational catalysts design: 1) Cr(IV) dominates at Al3+ site with all ethanol coverage, Al3+ site with high-coverage ethanediol, and Mg2+ site with low-coverage ethanol; 2) Cr(III) dominates at Al3+ and Mg2+ sites with low-coverage ethanediol; 3) Cr(II) dominates at Mg2+ site with high-coverage ethanol or ethanediol. Results agree finely with experimental observations available, and significant new insights have been provided for Cr management and recycling. Detailed electronic structure and vibrational analyses, which can also guide future experimental studies, manifest that Cr(VI) reduction progresses are effectively monitored by ESR and FT-IR techniques.

Innovative hydrogen release from sodium borohydride hydrolysis using biocatalyst-like Fe2O3 nanoparticles impregnated on Bacillus simplex bacteria

For the first time in this innovative study, microorganisms such as Bacillus simplex bacteria, mostly used in biological activity studies, are used as a bio-supporter agent of iron to release hydrogen from sodium borohydride hydrolysis at 25.0 ± 0.1 °C. The goal is to investigate thoroughly sodium borohydride hydrolysis catalyzed by Fe2O3 nanoparticles impregnated on microorganism such as Bacillus simplex (BS) bacteria (Fe2O3@BS NPs) known with strong antibacterial properties, which makes innovative them a candidate for hydrolysis reaction. This study was focused on the preparation, identification, and catalytic use of biocatalyst-like Fe2O3@BS NPs for hydrogen release from the sodium borohydride hydrolysis at 25.0 ± 0.1 °C. The characterization results made after and before hydrolysis reaction using by SEM/SEM-EDX, FT-IR, XRD, UV–vis, XPS, DLS, ELS Zeta potential, ESR, and TEM techniques reveal the formation of highly active, stable, durable, and long-lived biocatalysts-like Fe2O3@BS NPs.

PH-controlled mechanism of photocatalytic RhB degradation over g-C3N4 under sunlight irradiation.

Photocatalysis of dye degradation is one of green and cheap technologies for solving environmental pollution. Whereas it is rarely concerned that the degradation process varied with the change of solution condition, this work studied the influence of hydrion in the solution on the photodegradation process of Rhodamine B (RhB) over g-C3N4. The photocatalytic activity of RhB degradation was enhanced gradually with increased hydrion content in the system. The efficiency for RhB degradation over g-C3N4 in weak acidic system with interference of multiple metal-ions still reached near 95% after 30min of natural sunlight irradiation. A large amount of oxidation species and the hydroxylation mineralization process were induced by increasing the hydrion concentration. Two degradation processes for deethylation of four ethyl groups and the direct chromophoric degradation were discovered and proved by multifarious intermediates in different systems using the ESR technique, LC/MS and GC/MS analysis. In addition, the photosensitization played a critical role in the RhB degradation. A feasible degradation mechanism was proposed for the RhB degradation based on the experimental results.

Perovskite Based Photocatalyst for Wastewater Treatment: Green Approach of Environmental Sustainability

Persistent organic substances in wastewater are creating serious problems to the living world as well as to the environment, thereby creating huge detrimental impact on the ecosystem. In view of the grave situation, removal of the persistent organic substances from wastewater effluent holds a great promise to balance the ecosystem and to sustain societal impact value. In this respect, perovskite based photocatalysts have achieved remarkable attention to the scientific community due to their unique structural features and flexibility of composition. Again, surface polarization and electric dipole-dipole interaction in the perovskite material make them attractive for photocatalytic application. This review paper summarized the photocatalytic activity of perovskite materials and their modification to enhance catalytic activity for wastewater treatment. The modification in perovskite has been done to reduce bandgap energy for enhanced visible light activity, separation of charge carriers for their long lifetime, and fast photocatalytic reaction. The recent investigation of ABO₃ type perovskite, layered perovskite, and halide type of perovskite photocatalysts have been discussed detailly. The modification of corresponding perovskites by doped and formation of heterojunction is investigated carefully. The formation and identification of reactive oxygen species (ROS) and their degradation mechanism by trapping experiment and ESR technique has been summarized here. Finally, large scale with energy and environmental related research should be processed for a permanent solution of wastewater problem.

Çanakkale Boğazı, Özbek Denizel Sekisi Oluşum Yaşı için ESR Tekniği ile bir Ön Değerlendirme

Çalışmamızda incelediğimiz Özbek denizel sekisi deniz kıyısından 4 km içeride olup Çanakkale boğazı civarında, tespit edilen diğer denizel sekilere nispetle en yüksekte olanıdır. Marmara kıyılarında da yaygın olarak görülen denizel sekilerin oluşmasına sebebiyet veren düşey hareketlerin Marmara bölgesinin tektoniğini ve ayrıca boğazla-rın oluşumunu anlamak açısından anahtar bilgiler barındırdığı düşünülmektedir. Sekide Geç Pleistosendeki Akde-niz koşullarını temsil eden bol miktarda Ostrea edulis kavkıları tanımlanmıştır. Seki ESR tarihlendirme tekniği ile 16.2 ± 1.8 ka olarak tarihlendirilmiştir. O devirdeki küresel deniz seviyesi dikkate alındığında sekinin günümüze kadar toplamda yaklaşık olarak 250 metre kadar yükseldiği anlaşılmaktadır. Çanakkale Boğazının Akdeniz ile Marmara bağlantısını sağladığından beri bölgenin jeodinamik olaylarla yükseldiği ve bu süreçte boğaz tabanının derine kazıldığı düşünülmektedir. Tarihlendirme sonucuna göre bölgenin çok geniş bir sahaya yayılan batı Anado-lu’nun yükselmesi olayı ile bağlantılı olarak yükselmiş olabileceği fikri öne çıkmıştır. Varlığı yeni verilerle artarak desteklenen yer kabuğunun altındaki astenosferin yukarı yönlü akımının etkileri, araştırma alanının içinde olduğu geniş bir bölgenin yükselmesine sebep olur. Bu yükselmenin deniz kıyısında oluşan denizel fosilli birimleri bölgeyle beraber yükseklere taşıyıp denizel sekilerin gelişimine sebebiyet verdiği düşünülmektedir. Diğer taraftan, seki birim-leri çok ileri derecede mangan’ca kirlenmiş olduğundan numunelerin analizinde sorunlar vardır. Tarihlendirmeye tâbi tutulan numune sayısının çokluğu güvenilirliğin denetlenmesi bakımından bir gerek-sinim olmakla beraber haklarında yok denecek kadar az bilgi bulunan bölgedeki yüksek sekilere dair edindiğimiz ön nitelikteki tarihlen-dirme sonuçları bölgenin geçmişindeki jeodinamik olaylar hakkında, bölgedeki diğer yer-bilimsel verilerle tutarlı bir model kurulabilmesini sağlamıştır

Preparation, spectral characterization, ESR measurements and DFT calculations of Schiff base copper(II) complex

The title compound ([CuClL(H2O)]·2H2O) were synthesized. The copper(II) complex in square planar geometry were identified by using elemental analysis, magnetic susceptibility, mass spectra, FT-IR, UV-Vis. and ESR techniques. DFT calculations at the UB3LYP/LANL2DZ level of theory were conducted to obtain vibrational and electronic properties of the copper(II) complex. Vibrational assignments of the observed infrared spectra of title compound were carried out based on the calculated potential energy distributions (PEDs). The sensitive measurement results indicated that the observed values were reasonable. The energy values were determined to describe electronic properties of the title molecules. Furthermore, NBO analysis was performed to analyze the hyper-conjugative stability of the molecule, molecular orbital interaction and charge delocalization.

Black phosphorus nanosheets and ZnAl-LDH nanocomposite as environmental-friendly photocatalysts for the degradation of Methylene blue under visible light irradiation

Environmental-friendly photocatalysts and high utilization of solar energy have attracted much attention; hence, it is important to develop highly efficient and non-toxic photocatalysts. As a novel two-dimensional semiconductor, black phosphorus nanosheets (BPNs) have gotten extensive solicitude due to their tunable bandgap and high carrier mobility. Here, we report a new kind of environmental-friendly nanocomposite consisting of ZnAl-layered double hydroxides (LDH) and BPNs, and is obtained by electrostatic self-assembly method. The acquired photocatalysts were studied by XRD, TEM, EDX, UV–Vis diffuse reflectance spectra, mott-schottky, EIS and ESR techniques so as to gain the information on morphology, structure and properties. Compared to pristine ZnAl-LDH and BPNs, the composite photocatalyst shows the best photocatalytic activity for methylene blue (MB) degradation under visible light irradiation, and the 99% of MB was degraded in 80 min. The improvement of photocatalytic performance is mainly because BPNs provide an additional transfer channel of electrons and holes. The nanocomposites have opened up a new idea to construct black phosphorus (BP) based photocatalysts for environmental remediation.

Synthesis and Characterization of Chemical Structures, Thermal Decomposition and Biological Properties of Novel Copper (II) Bio- Based Surfactants

Background: Thermal degradation has attracted the attention of scientific community throughout the world due to its multiple applications in environment, energy, waste water treatment, pollution control, green chemistry, etc. Objective: The present work deals with the study of synthesis and characterization of thermal and biological properties of novel copper complex. Methods: Chemical structures of copper (II) sesame 2-amino-6-ethoxy benzothiazole complex were confirmed by IR, NMR, and ESR techniques. Thermal and biological properties were analysed by Thermogravimetry (TGA) and antimicrobial activity determination against Staphylococcus aureus. Results: The TGA study reveals that copper (II) sesame 2-amino-6-ethoxy benzothiazole complex undergoes stepwise thermal degradation of ligand-soap bond of complex and unsaturated and saturated fatty acid components of edible oils. The complex exhibit significant antimicrobial activities against Staphylococcus aureus. Conclusion: This study provides relevant basic information on the thermal and antimicrobial properties of new copper (II) bio-based surfactants, as well as an explicit relationship structure-biological activity for their potential use as safe and green chemicals.

New insights into the mechanisms of tartaric acid enhancing homogeneous and heterogeneous copper-catalyzed Fenton-like systems

The specific roles of tartaric acid (TA), as an eco-friendly ligand, in homogeneous and heterogeneous copper-catalyzed systems were systematically revealed and new mechanisms of TA enhancing the three Fenton-like processes were proposed to provide a theoretical significance in overcoming the deficiency of conventional Fenton processes. The results identified hydroxyl radical (•OH) as the main species responsible for the simultaneous decomposition of TA and metronidazole (MNZ) according to TOC removal. The ESR technique was used to detect superoxide radicals (•O2−), carbon-centered radical (•R) and hydrogen radical (•H) in the Cu2+/TA/H2O2 system, which contributed to the acceleration of the Cu2+/Cu+ redox cycle. The enhancing effect of TA on the homogeneous process was ascribed to the formation of a soluble complex with Cu2+, which favored the pH range extension, Cu+ oxidation, and radical generation. Moreover, the adsorption of TA on the catalysts surface promoted the consumption of H2O2, inducing •OH generation. The formed surface complex (≡Cu2+-TA) also accelerated the regeneration of ≡Cu+, which was confirmed by density functional theory (DFT) calculation and surface characterization analysis (SEM, XRD, and XPS). The possible degradation pathways of MNZ in TA-modified Fenton-like system were also clarified.

Insights into coke formation during thermal reaction of six different distillates from the same coal tar

The high yields of coke and tar pitch relating to volatile reactions can cause plug in the product lines during low temperature pyrolysis of low-rank coals. To study the potential transformation of volatile into coke during its migration in the pyrolysis process, six distillates and their blends from the same coal tar were heated at 400–600 °C. The composition, radicals of six distillates and coke structure were characterized by GC × GC–MS, ESR and Raman techniques, respectively. The results show that the coke yields increase with temperature during thermal reaction for all six distillates. When light oil and pitch are blended, the interaction between the two distillates compresses the transformation of volatile into coke above 500 °C. This can be ascribed to that the reactive hydrogen radicals generated from light oil may weaken the bonding between large molecules. By contrast, other distillates (phenolic oil, naphthalic oil, wash oil and anthracene oil) promote coke formation, resulting in higher coke yields than expected. It is also observed that the highest extent of interaction occurs between phenolic oil and pitch, which may be related to the high content of oxygen containing compounds in phenolic oil and the high electron density of the compounds in pitch.

Rational design of α-Fe2O3 nanocubes supported BiVO4 Z-scheme photocatalyst for photocatalytic degradation of antibiotic under visible light

The Z-scheme BiVO4/α-Fe2O3 photocatalyst was synthesized by a simple hydrothermal method. The photocatalyst is composed of α-Fe2O3 nanocubes with a regular cubic structure and the BiVO4 particles distributed on the surface of the α-Fe2O3 nanocubes. The photocatalytic performance of Z-scheme BiVO4/α-Fe2O3 photocatalyst was investigated in terms of its capacity for photodegradation of tetracycline hydrochloride. Improved photocatalytic activity was observed for Z-scheme BiVO4/α-Fe2O3 photocatalyst compared with pure BiVO4 and α-Fe2O3 nanocubes under visible light irradiation. Studies of its morphology, physicochemical properties and photoelectrochemical behaviors demonstrated that BiVO4 loading on the surface of α-Fe2O3 nanocubes forms a Z-scheme heterojunction, which increases the specific surface area and significantly promotes the separation of photoinduced carriers. The main active species were determined to be OH and h+ by ESR technique and trapping experiments. We propose a possible photocatalytic mechanism of Z-scheme BiVO4/α-Fe2O3 photocatalyst system. This study may also provide a novel and eco-friendly demonstration of a useful strategy for the design and preparation of special structure photocatalytic materials.

A Way for Derived Carbon Materials by Thermal Etching Hybrid Borate for Electrochemical CO2 Reduction

Two hybridized skeleton borates [Zn(en)2]·[B7O12(OH)] (1; en = ethylenediamine) and [Cd(1,3-dap)2]·[B5O8(OH)]·H2O (2; 1,3-dap = 1,3-diaminopropane) were solvothermally synthesized. The boron oxide clusters formed 2D planes, and these planes formed a 3D structure through co-oxygen links of metal complexes. Herein, a novel strategy has been developed, i.e., the derived guest carbon materials from semi-decomposed borate are incorporated into the void of host borate crystals in situ during the thermal etching process. Moreover, the effect of temperature on fluorescence of derived carbon materials was studied. By controlling the calcining temperature, carbon dots with obvious free radicals can be found via ESR technique. Carbon dots in the ethanol phase exhibited variable photoluminescence. Furthermore, it derived semi-decomposition carbon materials via thermal etching based on compounds 1 and 2. In an hydrogen cell reactor, carbon material Zn-based catalyst 1-200 catalyzes CO2 reduction to CO with a selectivity that reaches 50.8% at -1.4 V vs RHE.