Spherical Nanostructures Research Articles

Nanosphere Lithography-Based Fabrication of Spherical Nanostructures and Verification of Their Hexagonal Symmetries by Image Analysis

Nanosphere lithography (NSL) is a cost- and time-effective technique for the fabrication of well-ordered large-area arrays of nanostructures. This paper reviews technological challenges in NSL mask preparation, its modification, and quality control. Spin coating with various process parameters (substrate wettability, solution properties, spin coating operating parameters) are discussed to create a uniform monolayer from monodisperse polystyrene (PS) nanospheres with a diameter of 0.2–1.5 μm. Scanning electron microscopy images show that the PS nanospheres are ordered into a hexagonal close-packed monolayer. Verification of sphere ordering and symmetry is obtained using our open-source software HEXI, which can recognize and detect circles, and distinguish between hexagonal ordering and defect configurations. The created template is used to obtain a wide variety of tailor-made periodic structures by applying additional treatments, such as plasma etching (isotropic and anisotropic), deposition, evaporation, and lift-off. The prepared highly ordered nanopatterned arrays (from circular, triangular, pillar-shaped structures) are applicable in many different fields (plasmonics, photonics, sensorics, biomimetic surfaces, life science, etc.).

How β-cyclodextrin- loaded mesoporous SiO2 nanospheres ensure efficient adsorption of rifampicin.

In this study, β-CD@mesoporous SiO2 nanospheres (β-CD@mSi) were prepared by loading β-cyclodextrin (β-CD) onto mesoporous silica nanospheres through an in situ synthesis. This not only solved the defect of β-CD being easily soluble in water, but also changed the physical structure of the mesoporous silica nanospheres. FTIR and XPS results showed that β-CD was successfully loaded onto mesoporous silica nanospheres (mSi), while enhancing the adsorption effect. β-CD@mSi with a monomer diameter of about 150nm were prepared. At a temperature of 298k, the removal efficiency of a 100mg/L solution of rifampicin can reach 90% in 4h and the adsorption capacity was 275.42mgg-1at high concentration. Through the calculation and analysis of adsorption kinetics, adsorption isotherms and adsorption thermodynamics based on the experimental data, the reaction is a spontaneous endothermic reaction dominated by chemical adsorption. The electron transfer pathway, structure-activity relationship and energy between β-CD@mSi and rifampicin were investigated by quantum chemical calculations. The accuracy of the characterization test results to judge the adsorption mechanism was verified, to show the process of rifampicin removal by β-CD@mSi more clearly and convincingly. The simulation results show that π-π interaction plays a major interaction in the reaction process, followed by intermolecular hydrogen bonding and electrostatic interactions.

Residue-Specific Insights into the Intermolecular Protein-Protein Interfaces Driving Amelogenin Self-Assembly in Solution.

Amelogenin, the dominant organic component (>90%) in the early stages of amelogenesis, orchestrates the mineralization of apatite crystals into enamel. The self-association properties of amelogenin as a function of pH and protein concentration have been suggested to play a central role in this process; however, the large molecular weight of the self-assembled quaternary structures has largely prevented structural studies of the protein in solution under physiological conditions using conventional approaches. Here, using perdeuterated murine amelogenin (0.25 mM, 5 mg/mL) and TROSY-based NMR experiments to improve spectral resolution, we assigned the 1H-15N spectra of murine amelogenin over a pH range (5.5 to 8.0) where amelogenin is reported to exist as oligomers (pH ≤∼6.8) and nanospheres (pH ≥∼7.2). The disappearance or intensity reduction of amide resonances in the 1H-15N HSQC spectra was interpreted to reflect changes in dynamics (intermediate millisecond-to-microsecond motion) and/or heterogenous interfaces of amide nuclei at protein-protein interfaces. The intermolecular interfaces were concentrated toward the N-terminus of amelogenin (L3-G8, V19-G38, L46-Q49, and Q57-L70) at pH 6.6 (oligomers) and at pH 7.2 (nanospheres) including the entire N-terminus up to Q76 and regions distributed through the central hydrophobic region (Q82-Q101, S125-Q139, and F151-Q154). At all pH levels, the C-terminus appeared disordered, highly mobile, and not involved in self-assembly, suggesting nanosphere structures with solvent-exposed C-termini. These findings present unique, residue-specific insights into the intermolecular protein-protein interfaces driving amelogenin quaternary structure formation and suggest that nanospheres in solution predominantly contain disordered, solvent-exposed C-termini.

Yersinia enterocolitica-Derived Outer Membrane Vesicles Inhibit Initial Stage of Biofilm Formation.

Yersinia enterocolitica (Y. enterocolitica) is an important food-borne and zoonotic pathogen. It can form biofilm on the surface of food, increasing the risk to food safety. Generally, outer membrane vesicles (OMVs) are spherical nanostructures secreted by Gram-negative bacteria during growth. They play a role in biological processes because they contain biologically active molecules. Several studies have reported that OMVs secreted by various bacteria are associated with the formation of biofilms. However, the interactions between Y. enterocolitica OMVs and biofilm are unknown. This study aims to investigate the effect of Y. enterocolitica OMVs on biofilm formation. Firstly, OMVs were extracted from Y. enterocolitica Y1083, which has a strong biofilm-forming ability, at 15 °C, 28 °C and 37 °C and then characterized. The characterization results showed differences in the yield and protein content of three types of OMVs. Next, by co-culturing the OMVs with Y. enterocolitica, it was observed that the OMVs inhibited the initial stage of Y. enterocolitica biofilm formation but did not affect the growth of Y. enterocolitica. Furthermore, biofilm formation by Salmonella enteritidis and Staphylococcus aureus were also inhibited by OMVs. Subsequently, it was proved that lipopolysaccharides (LPS) in OMVs inhibited biofilm formation., The proteins, DNA or RNA in OMVs could not inhibit biofilm formation. Bacterial motility and the expression of the biofilm-related genes pgaABC, motB and flhBD were inhibited by LPS. LPS demonstrated good anti-biofilm activity against various bacteria. This study provides a new approach to the prevention and control of pathogenic bacterial biofilm.

Evaluation of the Datura peels derived biochar-based Anode for enhancing power output in microbial fuel cell application

Activated biochar utilizing Datura metel peel was synthesized using pyrolysis at 800oC and activated using KOH. The resulting biochar was investigated as an anode material in a Pseudomonas aeruginosa powered microbial fuel cell (MFC) utilizing acetate as the substrate for the first time. The average chemical oxygen demand (COD) elimination was 85.4% in closed circuit mode. The maximum power production was observed in MFC containing 1 mg/cm2 biochar impregnated anode with a peak power density measured at 584.2 mW/m2. The results of biochar characterization using Field Emission Scanning Electron Microscope (FE-SEM) illustrates the presence of spherical globular texture which indicates the nano spherical structure of carbon nanoparticles in the biochar. The porous texture and interlinked characteristics of carbon nano-spheres can significantly enhance the diffusion of electrolyte ions. The confocal laser scanning microscopy (CLSM) results show a high number of cell biomass on 1 mg/cm2 biochar impregnated anode, indicating that 1 mg/cm2 biochar promotes enhanced biofilm formation. These results emphasize the utilization of biochar as electrodes in MFCs to allow for simultaneous wastewater treatment and electricity generation .

Controllable synthesis of nano-spherical and spinel structure hausmannite for asymmetric supercapacitor electrode application with long-term cyclic stability and its photocatalytic activity

Spinel structured materials have been developed as a potential candidate for energy storage applications due to their tunable electronic and structural properties. The nano spherical Mn3O4 spinel structure was synthesized using a polyvinylpyrrolidone (PVP) assisted hydrothermal approach. Owing to the smaller nano spherical architecture, and the impressive surface properties, the Mn3O4 shows outstanding surface characteristics to provide more reaction centers and shorten the ion transport path. Here, the addition of PVP reduces the battery-like diffusive behavior of the Mn3O4 electrode, induces capacitive behavior, and improves both high energy density and power density in a single material and cycling stability. In three-electrode configurations, Mn3O4 exhibits specific capacitance (628.7 Fg−1 at 1 Ag−1) and long-term cyclic stability (94% at 100 mV s−1 for 5000 cycles) in 1 M Na2SO4 electrolyte. The asymmetric device offers a high energy density of 35.41 Wh kg−1 with a power density of 850 W kg−1 and cyclic stability of 96.5% after 10000 charge/discharge cycles at 12 Ag−1. Density functional theory (DFT) is explained by electronic structural features and further investigated the photocatalytic activity of Mn3O4 samples on the model dye of Methylene Blue degradation.

Adhesive AuNP tape-mediated hierarchical assembly of multicenter DNA nanocomplexes for tumor cell nucleus-targeted staged drug delivery in vivo

Developing DNA nanostructures as delivery vectors into organelles is a key technical barrier because of their innate poor pharmacokinetic properties. Herein, we propose a unique concept for high precision cancer therapy by using small gold nanoparticles (AuNPs) as adhesive nano-tapes to fold a long string of aptamer-attached tetrahedral DNA pearls (Apt-Nano-Tetra) into a spherical multicenter DNA nanostructure that can serve as a nucleus-targeted drug delivery carrier (Apt-ADMC) with a 75～85 times enhanced doxorubicin (Dox)-loading capacity. After specifically entering target tumor cells, Dox-Apt-ADMC is disassembled into individual AuNPs surrounded by short Apt-Nano-Tetra, finally reaching cell nucleus and causing cell apoptosis. Even if Dox-Apt-ADMC is treated with fetal bovine serum for 12 h, the drug delivery ability is not compromised, contributing to high functional stability in circulation system. As such, the systemically-administrated Dox-Apt-ADMC shows 7 times enhanced tumor accumulation and almost 100% inhibits tumor growth without detectable systemic toxicity.

Mimicking the structure of Morpho butterfly wing surface: a highly reflective nanostructure assembled by nanospheres

Inspired by the surface structure of Morpho butterfly wings, we theoretically propose a biomimetic nanosphere structure with high optical reflectivity. By adjusting the geometric parameters and material parameters of the nanostructure, we obtain reflectivity >99 % in a certain band; the high-reflection bandwidth depends on the period width, filling factor, and number of nanospheres. Its high-reflectivity bandwidth is less dependent on the incidental light angle compared with general single-layer or multilayer coatings for reflection enhancement. Unlike the biomimetic structures that are completely the same as the Morpho butterfly surface, this simplified structure can be assembled in ways other than photolithography and electron-beam lithography. We also analyzed several deviations of the structure, and the results show that our design allowed these deviations, which is helpful to achieving the effect of the structure in the preparation process. At the same time, the equivalent medium theory was used to analyze the nanostructure. The nanosphere structure has excellent potential applications in optical devices that require high reflectivity, such as laser resonant cavity and optical filters.

Reduced graphene oxide loaded with rich defects CoO/Co3O4 for broadband microwave absorption

Graphene-based microwave absorbing (MA) materials have been extensively studied due to their excellent physical properties. However, very few research has successfully achieved broader frequency MA materials while ensuring good wave absorption properties. In this work, we obtained reduced graphene oxide (RGO) modified with magnetic CoxOy nanoparticles by assembling Co nanoparticles onto graphene with a simple hydrothermal method followed by pyrolysis at different temperatures, possessing wideband broad bandwidth microwave absorbing capability. The electromagnetic parameters, attenuation constants, and impedance matching of the CoxOy/RGO composites pyrolyzed at different temperatures were analyzed to determine the optimum pyrolysis temperature for the CoxOy/RGO composites. After heat treatment at 500 °C, a large number of CoO/Co3O4 interfaces appeared. The minimum reflection loss of the sample reaches −67.2 dB and the effective absorbing bandwidth (EAB) (RL < −10 dB) is 9.1 GHz, covering the whole X, Ku, and K bands. It is worth noting that such a good microwave absorption performance is attributed to the fact that the structure of cobalt nanospheres can adjust the effective dielectric constant of the material, and the existence of CoO can promote dipole polarization and interfacial polarization process to improve impedance matching, so as to obtain a wider absorption effect.

Successional heterostructure MoS2-Ni3S2 nanospheres based on 3D nano-porous Ni: An efficient electrocatalyst for overall water splitting

A rich reserve, low-cost electrocatalyst with high-efficiency catalytic activity is supposed to be a promising substitute for Pt-based noble metal electrocatalysts. Herein, we produced a heterostructure MoS2-Ni3S2 nanosphere on 3D nano-porous Ni through a novel synthetic strategy. Benefiting from the unique nanospherical heterostructure MoS2-Ni3S2 catalyst exhibits relatively low overpotentials of η10 = 109 mV and Tafel slope of 81 mV dec−1 for HER, η10 = 130 mV and 91 mV dec−1 for OER. Using heterostructure MoS2-Ni3S2 as bifunctional electrocatalysts, a low cell voltage of 1.49 V was required to reach a current density of 10 mA cm−2. The outstanding performance of heterostructure MoS2-Ni3S2 is attributed to the fast charge transfer channel offered by the interface between MoS2 and Ni3S2 as well as the large surface area provided by the nanospherical structure. This work elaborates a feasible measure to realize the non-noble and high-efficiency electrocatalysts and is instructive for the design of interface engineering and nanostructures.

Biosynthesis, characterization and nonlinear optical response of spherical flake-shaped copper oxide nanostructures

The copper oxide nanoparticles (CuO NPs) were synthesized via solution combustion approach with Bengal gram powder as a fuel. The XRD analysis confirms the monoclinic structure of CuO NPs. FT-IR spectrum reveals the formation of CuO NPs. SEM studies show that the NPs are nearly spherical, and the elemental composition was confirmed by EDAX. The absorption spectra revealed a direct optical band gap of 1.50[Formula: see text]eV. DFT calculations were performed to determine the HOMO–LUMO energy bandgap and found to be 1.72[Formula: see text]eV, which is in good agreement with the experimental value. The Z-scan technique was used to investigate the third-order nonlinear optical (NLO) characteristics using DPSS continuous wave laser (532[Formula: see text]nm, 200[Formula: see text]mW). A high reverse saturation absorption and negative nonlinear refractions were observed. Third-order NLO parameters [Formula: see text], [Formula: see text] and [Formula: see text] were found to be [Formula: see text][Formula: see text]cm/W, [Formula: see text][Formula: see text]cm2/W and [Formula: see text][Formula: see text]esu, respectively. The CuO NPs also displayed strong optical limiting behavior with a limiting threshold of 2.11[Formula: see text]kW/cm2.

Effect of Calcination Temperature on Structural, Morphological and Optical Properties of Copper Oxide Nanostructures Derived from Garcinia mangostana L. Leaf Extract.

Synthesis of copper oxide (CuO) nanostructures via biological approach has gained attention to reduce the harmful effects of chemical synthesis. The CuO nanostructures were synthesized through a green approach using the Garcinia mangostana L. leaf extract and copper (II) nitrate trihydrate as a precursor at varying calcination temperatures (200–600 °C). The effect of calcination temperatures on the structural, morphological and optical properties of CuO nanostructures was studied. The red shifting of the green-synthesized CuO nanoparticles’ absorption peak was observed in UV-visible spectrum, and the optical energy bandgap was found to decrease from 3.41 eV to 3.19 eV as the calcination temperatures increased. The PL analysis shown that synthesized CuO NPs calcinated at 500 °C has the maximum charge carriers separation. A peak located at 504–536 cm−1 was shown in FTIR spectrum that indicated the presence of a copper-oxygen vibration band and become sharper and more intense when increasing the calcination temperature. The XRD studies revealed that the CuO nanoparticles’ crystalline size was found to increase from 12.78 nm to 28.17 nm, and dislocation density decreased from 61.26 × 1014 cm−1 to 12.60 × 1014 cm−1, while micro strain decreased from 3.40 × 10−4 to 1.26 × 10–4. From the XPS measurement, only CuO single phase without impurities was detected for the green-mediated NPs calcinated at 500 °C. The morphologies of CuO nanostructures were examined using FESEM and became more spherical in shape at elevated calcination temperature. More or less spherical nanostructure of green-mediated CuO calcinated at 500 °C were also observed using TEM. The purity of the green-synthesized CuO nanoparticles was evaluated by EDX analysis, and results showed that increasing calcination temperature increases the purity of CuO nanoparticles.

Homogenous Cr and C Doped 3D Self-Supporting NiO Cellular Nanospheres for Hydrogen Evolution Reaction.

Hydrogen evolution reaction (HER) is one promising technique to obtain high-purity hydrogen, therefore, exploiting inexpensive and high-efficiency HER electrocatalysts is a matter of cardinal significance under the background of achieving carbon neutrality. In this paper, a hydrothermal method was used to prepare the Cr-NiC2O4/NF (Ni foam) precursor. Then, the NiO-Cr-C/NF self-supporting HER catalyst was obtained by heating the precursor at 400 °C. The catalyst presents a 3D cellular nanospheres structure which was composed of 2D nanosheets. Microstructure characterization shows that Cr and C elements were successfully doped into NiO. The results of electrochemical measurements and density functional theory (DFT) calculations show that under the synergy of Cr and C, the conductivity of NiO was improved, and the Gibbs free energy of H* (∆GH*) value is optimized. As a result, in 1.0 M KOH solution the NiO-Cr-C/NF-3 (Ni:Cr = 7:3) HER catalyst exhibits an overpotential of 69 mV and a Tafel slope of 45 mV/dec when the current density is 10 mA·cm−2. Besides, after 20 h of chronopotentiometry, the catalytic activity is basically unchanged. It is demonstrated that C and Cr co-doping on the lattice of NiO prepared by a simple hydrothermal method and subsequent heat treatment to improve the catalytic activity and stability of the non-precious metal HER catalysts in an alkaline medium is facile and efficient.

Nanostars Carrying Multifunctional Neurotrophic Dendrimers Protect Neurons in Preclinical In Vitro Models of Neurodegenerative Disorders.

A challenge in neurology is the lack of efficient brain-penetrable neuroprotectants targeting multiple disease mechanisms. Plasmonic gold nanostars are promising candidates to deliver standard-of-care drugs inside the brain but have not been trialed as carriers for neuroprotectants. Here, we conjugated custom-made peptide dendrimers (termed H3/H6), encompassing motifs of the neurotrophic S100A4-protein, onto star-shaped and spherical gold nanostructures (H3/H6-AuNS/AuNP) and evaluated their potential as neuroprotectants and interaction with neurons. The H3/H6 nanostructures crossed a model blood–brain barrier, bound to plasma membranes, and induced neuritogenesis with the AuNS, showing higher potency/efficacy than the AuNP. The H3-AuNS/NP protected neurons against oxidative stress, the H3-AuNS being more potent, and against Parkinson’s or Alzheimer’s disease (PD/AD)-related cytotoxicity. Unconjugated S100A4 motifs also decreased amyloid beta-induced neurodegeneration, introducing S100A4 as a player in AD. Using custom-made dendrimers coupled to star-shaped nanoparticles is a promising route to activate multiple neuroprotective pathways and increase drug potency to treat neurodegenerative disorders.

Infection-activated lipopeptide nanotherapeutics with adaptable geometrical morphology for in vivo bacterial ablation

The nonselective membrane disruption of antimicrobial peptides (AMPs) helps in combating the antibacterial resistance. But their overall positive charges lead to undesirable hemolysis and toxicity toward normal living cells, as well as the rapid clearance from blood circulation. In consequence, developing smart AMPs to optimize the antimicrobial outcomes is highly urgent. Relying on the local acidity of microbial infection sites, in this work, we designed an acidity-triggered charge reversal nanotherapeutics with adaptable geometrical morphology for bacterial targeting and optimized therapy. C16-A3K4-CONH2 was proposed and the ε-amino groups in lysine residues were acylated by dimethylmaleic amide (DMA), enabling the generated C16-A3K4(DMA)-CONH2 to self-assemble into negatively charged spherical nanostructure, which relieved the protein adsorption and prolonged blood circulation in vivo. After the access of C16-A3K4(DMA)-CONH2 into the microbial infection sites, acid-sensitive β-carboxylic amide would hydrolyze to regenerate the positive C16-A3K4-CONH2 to destabilize the negatively charged bacterial membrane. In the meanwhile, attractively, the self-assembled spherical nanoparticle transformed to rod-like nanostructure, which was in favor of the efficient binding with bacterial membranes due to the larger contact area. Our results showed that the acid-activated AMP nanotherapeutics exhibited strong and broad-spectrum antimicrobial activities against Yeast, Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and methicillin-resistant Staphylococcus aureus (MRSA). Moreover, the biocompatible lipopeptide nanotherapeutics dramatically improved the dermapostasis caused by bacterial infection. The strategy of merging pathology-activated therapeutic function and morphological adaptation to augment therapeutic outcomes shows the great potential for bacterial inhibition. Statement of significanceThe overall positive charges of antimicrobial peptides (AMPs) lead to undesirable hemolysis and nonselective toxicity, as well as the rapid clearance from blood circulation. Infection-activated lipopeptide nanotherapeutics with adaptable geometrical morphology were developed to address these issues. The self-assembled lipopeptide was pre-decorated to reverse the positive charge to reduce the hemolysis and nonselective cytotoxicity. After accessing the acidic infection sites, the nanotherapeutics recovered the positive charge to destabilize negatively charged bacterial membranes. Meanwhile, the morphology of self-assembled nanotherapeutics transformed from spherical nanoparticles to rod-like nanostructures in the lesion site, facilitating the improved association with bacterial membranes to boost the therapeutic efficiency. These results provide new design rationale for AMPs developed for bacterial inhibition.

Effect of carboxymethyl konjac glucomannan coating on the stability and colon-targeted delivery performance of fucoxanthin-loaded gliadin nanoparticles

Fucoxanthin (FUC) is a hydrophobic carotenoid that has a protective effect on the colon. To exert the beneficial effects of FUC in the colon and expand its application in functional food, FUC was encapsulated in carboxymethyl konjac glucomannan (CMKGM)-coated gliadin nanoparticles (Gli-CMKGM NPs) in this paper. Gli-CMKGM NPs were prepared at pH 5.0 with Gli/CMKGM mass ratio of 1:1. The formation of Gli-CMKGM NPs was associated with hydrogen bonding, hydrophobic interactions and electrostatic attractions. Additionally, Gli-CMKGM NPs exhibited good stability to pH, salt, heating and storage. The results showed that FUC had been successfully encapsulated in Gli-CMKGM NPs, and the encapsulation efficiency of FUC-Gli-CMKGM NPs was significantly higher than that of uncoated FUC-Gli NPs. FUC-Gli-CMKGM NPs had a nano-spherical structure, and embedded FUC in Gli-CMKGM NPs improved their stabilities to photodegradation and thermal degradation. Furthermore, in vitro release and in vivo organ distribution studies showed that FUC-Gli-CMKGM NPs had an excellent colon targeting function. Overall, our findings illustrated the promise of CMKGM-coated Gli NPs for constructing targeted delivery systems for FUC.

Scavenger receptor-targeted plaque delivery of microRNA-coated nanoparticles for alleviating atherosclerosis

Atherosclerosis treatments by gene regulation are garnering attention, yet delivery of gene cargoes to atherosclerotic plaques remains inefficient. Here, we demonstrate that assembly of therapeutic oligonucleotides into a three-dimensional spherical nucleic acid nanostructure improves their systemic delivery to the plaque and the treatment of atherosclerosis. This noncationic nanoparticle contains a shell of microRNA-146a oligonucleotides, which regulate the NF-κB pathway, for achieving transfection-free cellular entry. Upon an intravenous injection into apolipoprotein E knockout mice fed with a high-cholesterol diet, this nanoparticle naturally targets class A scavenger receptor on plaque macrophages and endothelial cells, contributing to elevated delivery to the plaques (∼1.2% of the injected dose). Repeated injections of the nanoparticle modulate genes related to immune response and vascular inflammation, leading to reduced and stabilized plaques but without inducing severe toxicity. Our nanoparticle offers a safe and effective treatment of atherosclerosis and reveals the promise of nucleic acid nanotechnology for cardiovascular disease.

Hollow Mo2C nanospheres modified B-doped g-C3N4 for high efficient photocatalysts

Although graphitic carbon nitride (g-C3N4) is one of the most promising metal-free semiconductors in the field of photocatalytic hydrogen production, the preparation of efficient g-C3N4-based photocatalysts is still a challenge. Herein, the strategy of element doping and co-catalyst loading are employed to make an effective modification on g-C3N4. The Mo2C hollow nanospheres supported by porous B-C3N4 (B-doped g-C3N4) flakes, namely, B-C3N4/Mo2C photocatalysts are successfully constructed by the ultrasonic self-assembly-calcination approach. The unique Mo2C hollow nanospheres structures increases internal multiple visible light scattering, which facilitates light-harvesting, shortens the transport distance of carriers, and hence reduces the carriers recombination. Impressively, B-C3N4/Mo2C-35 exhibits excellent activity in photocatalytic hydrogen production, affording an H2 production rate up to 1696.4 µmol g−1 h−1, which is higher than B-C3N4/3 wt% Pt photocatalyst. Moreover, the apparent quantum efficiency of B-C3N4/Mo2C-35 at 420 nm is 2.12%. Mechanism studies suggest that this desired photocatalytic performance is attributed to a broader light absorption range, more reactive sites and faster carrier transfer rate than that of pure g-C3N4. This work develops a noble metal-free hollow nanosphere co-catalyst system and proposes new insight into the design of g-C3N4-based composite photocatalysts.

Effect of Organic Reagents on the Phase Structure of MnOx Porous Nanospheres: Catalytic Oxidation of Methanol at Low Temperatures

Effect of Organic Reagents on the Phase Structure of MnOx Porous Nanospheres: Catalytic Oxidation of Methanol at Low Temperatures

Structural, Morphological and Optical Study of Manganese Doped FeS (Mackinawite) Nanostructures by Chemical Bath Deposition (CBD) Technique

Abstract: Fe1-xMnxS thin films with concentration x=0.02, 0.04, 0.06, 0.08, 0.1 have been deposited on glass substrates by a simple Chemical Bath Deposition (CBD) method at 90 oC. The X-ray Diffraction analysis of deposited thin films revealed the growth of mono-phasic mackinawite (FeS) structure with crystallite size in the range from 4.06 to 5.95 nm as a function of manganese concentrations. The other structural parameters like stacking faults, dislocation density and lattice strain affirmed the improvement in crystal structure and phase stability in manganese doped FeS thin films. Scanning Electron Micrographs depicted the growth of nano-flakes and nano-flowers in case of pure FeS thin films while for manganese doped iron sulfide thin films, homogeneity of the deposited material was observed to improve with distinct boundaries of almost spherical nanostructures. The direct energy band gap of FeS mono-phasic thin films was observed to decrease from 2.23 to 1.89 eV as the concentration of manganese increases in host lattice. The prepared thin films with tunable optical properties would have potential applications in energy conversion and optoelectronic devices.