Surface Of Nanospheres Research Articles

A small-period long-period fiber grating biosensor based on immobilization of concanavalin A on polydopamine nanospheres for simultaneous detection of D-glucose and temperature

The accurate and sensitive monitoring of glucose levels plays a crucial role in diagnosing diabetes in clinical settings. In this work, a novel small-period long-period fiber grating (SP-LPG) biosensor was first developed for D-glucose detection based on the immobilization of concanavalin A (Con A) on polydopamine (PDA) nanospheres. SP-LPG was fabricated by using femtosecond laser direct writing technology and the obtained grating region was only 2.4 mm. The recognition element of D-glucose, Con A, was attached to the surface of PDA nanospheres. Due to the high specific surface area of PDA nanospheres, a large number of binding sites were available for Con A. The as-prepared sensor showed selective and sensitive to D-glucose measurement in the range of 10 nM to 10 mM and a low detection limit of 1.95 nM (S/N = 3) was achieved. Moreover, the small grating period of SP-LPG allows for the observation of Bragg reflection, which can be utilized for temperature sensing. This property eliminates the issue of temperature cross-sensitivity present in refractive index sensing. And the sensor exhibited a thermal sensitivity of 10 pm/°C within the range of 30 ∼ 100 °C. The developed sensor offers a convenient and efficient platform of simultaneously measuring multiple parameters, including target molecules and temperature, for real-time medical monitoring applications.

Pd@CuInP2S6 Core-Shell Nanospheres with Exceptional Hydrogen Evolution Capability and Stability in Both Alkaline and Acidic Media under Large Current Density Exceeding 1000mAcm-2.

By combining Pd with 2D layered crystal CuInP2S6 (CIPS) via laser irradiation in liquids, low-loading Pd@CIPS core-shell nanospheres are fabricated as an efficient and robust electrocatalysts for HER in both alkaline and acidic media under large current density (⩾1000mAcm-2). Pd@CIPS core-shell nanosphere has two structural features, i) the out-shell is the nanocomposite of PdHx and PdInHx, and ii) there is a kind of dendritic structure on the surface of nanospheres, while the dendritic structure porvides good gas desorption pathway and cause the Pd@CIPS system to maintain higher HER activity and stability than that of commercial Pt/C under large current densities. Pd@CIPS exhibits very low overpotentials of -218 and -313mV for the large current density of 1000mAcm-2, and has a small Tafel slope of 29 and 63mVdec-1 in 0.5mH2SO4 and 1mKOH condition, respectively. Meanwhile, Pd@CIPS has an excellent stability under -10 and -500mAcm-2 current densities and 50000 cycles cyclic voltammetry tests in 0.5mH2SO4 and 1mKOH, respectively, which being much superior to that of commercial Pt/C. Density functional theory (DFT) reveals that engineering electronic structure of PdHx and PdInHx nanostructure can strongly weaken the Pd─H bonding.

Ingenious entropy-driven DNA circuit intercommunicating with DNAzyme-powered DNA walker for dual-mode biosensing

Conventional DNA motor-based cascaded amplification methods have relative low DNA utilization efficiency and lack of self-feedback. Herein, a novel dual-mode biosensor of miRNA-155 was constructed based on a waste-free entropy-driven DNA circuit (EDC) cascaded with a self-feedback DNAzyme-powered DNA walker (DNAzyme Walker). The target (T)-triggered EDC generates two same single-stranded DNA (ssDNA) labelled with CdTe QDs as the signal probes (CdTe-O) and one double-stranded DNA (dsDNA) S/F to unlock the downstream blocked DNAzyme (D), which could then be activated in the presence of Mn2+ ions cofactor, and stochastically walk on the surfaces of SiO2 nanospheres, producing a lot of target analogue (T*) for self-feedback. With the assistance of Fe3O4@SiO2-capture DNA, the released CdTe-O can be rapidly extracted for the following self-validating dual-mode biosensing. The autocatalytic EDC module possesses a high operation efficiency and atomic economy, since it is not only hairpin- and leak-free, but also enzyme- and waste-free. The interactive EDC-DNAzyme Walker network-based fluorescent and colorimetric biosensor has a limit of detection low to 0.35 amol L−1 and 1.87 fmol L−1 at 3σ/S, respectively. The as-designed biosensor not only enables reliable and robust detection of miRNA expression levels, but also provides a remarkable signal cascaded amplification platform with self-feedback and high atom economy.

Upcycling sugar beet waste into sustainable organo-nanocatalysis for carbon dioxide fixation and cyclic carbonate synthesis: a research design study

Environmental pollution is a major global issue due to the increase of various pollutants all over the world. Enhancing pollutant remediation strategies for environmental sustainability necessitates increasing the efficiency of conventional methods or introducing innovative approaches. Nanotechnology, particularly carbon-based nanomaterials, offers substantial promise due to their high surface area and absorption potential. Concurrently, organocatalysts have emerged as sustainable and versatile alternatives to traditional metal-based catalysts in modern chemical research. This study highlights the synthesis and application of organo-nanocatalysts derived from biomass, specifically a spherical carbon nanocatalyst synthesized from sugar beet pulp. This novel green catalyst, characterized by high selectivity and efficiency, successfully converts epoxides and CO2 into valuable cyclic carbonates under solvent-free conditions. The hydroxyl groups on the Sugar Beet-derived Carbon NanoSphere (SCNS) surface act as Bronsted acid sites, facilitating epoxide activation via hydrogen bonding. The integration of carbon-based nanomaterials and organocatalysis represents a promising, sustainable solution for pollutant remediation and green chemistry advancements.Graphical

Dual-modal lateral flow immunoassay based on cauliflower-like ReS2@Pt core-shell nanospheres mediated ultra-sensitive detection of deoxynivalenol in food samples

Deoxynivalenol (DON) is a highly toxic secondary metabolite that poses a substantial threat to global human and animal health. However, existing detection technologies are often constrained by limited sensitivity, poor selectivity, or the high costs associated with instrumentation. Consequently, the development of rapid, low-cost, and highly sensitive biosensors for the detection of DON is of paramount importance for ensuring food safety. In this study, we synthesized the precursor of ReS₂ nanospheres using a relatively simple one-step hydrothermal method. Subsequently, Platinum (Pt) was grown in situ on the surface of the ReS₂ nanospheres via hydrothermal reduction, resulting in the formation of cauliflower-like ReS₂@Pt nanospheres. These spheres offer notable advantages, including strong colorimetric signal brightness and high anti-body loading efficiency. Surface modification with platinum significantly enhances peroxidase-like activity, broadening the detection range and improving sensitivity. Leveraging this innovation, we developed Colorimetric-LFIA (CR-LFIA) and Catalytic-LFIA (CL-LFIA) assays. Under optimized conditions, the limit of detection (LOD) for DON was determined to be 0.018 ng/mL for CR-LFIA and 6.5 pg/mL for CL-LFIA, representing 5 times and 16 times improvement over AuNPs-based LFIA (0.111 ng/mL), respectively. Moreover, the detection linear range of CL-LFIA is expanded by 2.5 times compared to CR-LFIA. Validation with real samples demonstrated recovery rates between 90.33% and 110.64%, affirming method stability and repeatability. The developed dual-modal LFIA detection system (D-LFIA) employing ReS2@Pt NPs holds promise for ultra-sensitive detection, with potential applications in expanding the detection range of various substances.

Gold nanoclusters and amino-modified mesoporous silica-encapsulated carbon dot fluorescence nanosensors combined with LightGBM algorithm for ultra-fast detection of Co2+

In this study, we develop a novel ratiometric fluorescent nanosensor for the detection excess Co2+ in soil. This fluorescent nanosensor is fabricated using mesoporous silica-encapsulated nitrogen-doped carbon dots (N-CDs@mSiO2) and gold nanoclusters stabilized by bovine serum albumin (BSA-AuNCs). The green fluorescence of the carbon dots within the mesoporous silica spheres (mSiO2) serves as an internal reference signal. The red fluoresence BSA-AuNCs are covalently connected onto the surface of amino-functionalized nanospheres (N-CDs@mSiO2-NH2), providing the response signal. This nanosensor has dual emission peaks at 520 nm and 650 nm under excitation wavelength of 380 nm. The addition of Co2+ to this nanosensor causes the fluorescence quenching at 650 nm while the green fluorescence at 520 nm remains unchanged, resulting in fluorescence color change from yellow to green. The developed ratiometric fluorescence nanosensor exhibits excellent selectivity to Co2+ with a range of 2.00–200.00 μM and a detection limit as low as 0.74 μM. In addition, a Co2+ prediction model is developed using the Light Gradient Boosting Machine (LightGBM) algorithm. The entire detection process is within 10 s and the model prediction value is as high as 0.991 on average. This shows that the proposed fluorescent nanosensor, optimized with the LightGBM algorithm, provides an efficient, environmentally friendly and potentially practical solution for Co2+ detection.

Inorganic/organic hybrid interfacial internal electric field modulated charge separation of resorcinol-formaldehyde resin for boosting photocatalytic H2O2 production

The strategy of inorganic/organic semiconductor material hybridization is of great significance for the development of highly active photocatalysts. Resorcinol-formaldehyde (RF) resin with a special donor-acceptor (D-A) structure shows excellent performance in the photocatalytic production of H2O2. However, the lack of an internal driving force for the separation and transfer of photogenerated electrons and holes in RF resin greatly limits the performance of H2O2 production. Herein, an inorganic/organic hybrid core-shell structure ZnS@RF photocatalyst was prepared by directionally induced coating of RF resin shells of different thicknesses on the surface of monodisperse ZnS nanospheres. Consequently, the photocatalytic H2O2 performance of ZnS@RF with the optimal RF resin shell thickness reaches 367.9 μmol L−1, which is 69 and 2 times that of ZnS and HRF, respectively. Density functional theory (DFT) calculations and related characterization results collectively demonstrate that the excellent photocatalytic H2O2 production performance of ZnS@RF photocatalyst is mainly attributed to the internal electric field (IEF) formed at the hybrid interface of ZnS and RF heterojunction and the optimization of RF shell thickness, which significantly enhances the separation and transfer of photogenerated carriers and modulates the interfacial catalytic reaction kinetics. This work opens up an avenue for designing inorganic/organic hybrid heterojunction photocatalyst materials with excellent photocatalytic activity.

Ppb-level H2 gas-sensor based on porous Ni-MOF derived NiO@CuO nanoflowers for superior sensing performance

Nickel oxide (NiO) is an optimal material for precise detection of hydrogen (H2) gas due to its high catalytic activity and low resistivity. However, the solid structure of NiO imposes limitations on the gas response kinetics of H2 gas molecules, resulting in a slower electron–hole transit and reduced gas response value. Herein, a unique NiO@CuO NFs with porous sharp-tip and nanospheres morphology was successfully synthesized by using a metal–organic framework (MOF) as a precursor. The fabricated porous 2 wt% NiO@CuO NFs describes outstanding selectivity towards H2 gas, including a high sensitivity of response value (170–20 ppm at 150 °C), is almost 28.3 % higher than that of porous Ni-MOF, low detection limit (300 ppb) with a notable response (21), short response and recovery times at (300 ppb, 40/63 s and 20 ppm, 100/167 s), exceptional long-term stability and repeatability. The study also explored the impact of relative humidity to evaluate the sensor performance under real-world conditions. The boosted hydrogen dioxide sensing properties may be attributed to synergistic effects of numerous factors including p-p heterojunction at the interface between NiO and CuO nanoflowers, especially a porous sharp-tip MOF structure and rough surface of nanospheres as well as the chemical sensitization effect of NiO. This research offers a viable method for creating unique MOS heterostructures from Ni-MOF and CuO that have unique morphologies and compositions that could be used for H2 gas sensing applications.

Fe3O4/AM-PAA/Ni nanomagnetic spheres: A breakthrough in in-situ catalytic reduction of heavy oil viscosity

In-situ catalytic technology for heavy oil reservoirs is widely regarded as one of the most promising methods for heavy oil extraction. However, its large-scale application faces significant challenges due to the lack of efficient stable catalysts, and issues related to the dispersion of catalysts during the injection process. This study introduces a modified nanomagnetic sphere, Fe3O4/AM-PAA/Ni, with catalytic and surface-active properties. With a 1 % mass fraction of Fe3O4/AM-PAA/Ni and 1 % tetrahydronaphthalene (hydrogen donor) at 180°C, heavy oil viscosity dropped by 94.21 %, and asphaltenes and resin reduced by approximately 20 %. Core flooding and alternating magnetic field experiments demonstrated superior dispersion and heating effects for Fe3O4/AM-PAA/Ni nanoparticles compared to traditional Fe3O4. Mechanism analysis revealed that the unpaired electrons and d-orbitals on Fe3O4/AM-PAA/Ni’s transition metals facilitated hydrocarbon chain breakdown and interaction with heteroatoms, while nanoscale nickel enhanced catalytic activity for C-S bond cleavage, further reducing oil viscosity. The amphiphilic polymers on the surface of magnetic nanospheres significantly enhanced the dispersion of the catalyst in heavy oil, increasing the reaction contact area and thereby improving the catalytic performance. This research not only offers vital theoretical insights and practical strategies for efficient heavy oil extraction but also paves the way for advancements in reservoir in-situ modification technologies, showcasing significant application potential and academic value.

Synthetic opal decorated by Co and Ce oxides as a nanoreactor for the catalytic CO oxidation

Macroporous synthetic opal grown from non-porous silica nanoparticles and decorated by Co and Ce oxides was applied for the catalytic CO oxidation in the inert (TOX) and H2-rich (PROX) gas mixtures. Prepared materials were studied by methods of SEM, TEM, EDX, XRD, XPS and FTIR spectroscopy. The relationship between synthesis conditions, structure, and catalytic behavior of composites is discussed. The best Co-O-Ce interaction and the highest activity in the CO-TOX and PROX are achieved when cerium oxide was added prior to the addition of cobalt oxide. In this case highly dispersed particles of Co3O4 and CeO2 are located in close proximity on the silica surface and anchored between the opal spheres. The use of Co/Ce decorated synthetic opal as a nanoreactor for the catalytic oxidation of CO in the H2 excess makes it possible to achieve 99.5 % conversion of CO at 150°C, the high efficiency and selectivity of the process are maintained in multiple cyclic tests in heating and cooling modes. The synergistic activity of Co and Ce oxides was observed when they both were located together on the outer surface of non-porous SiO2 nanospheres. These results are superior to known data for other catalysts based on Co and Ce oxides.

KOH-activated hollow carbon spheres with surface functionalization for high-capacity and long-cycle-life lithium-selenium batteries

Lithium-selenium (Li-Se) batteries are considered promising alternatives to lithium-ion batteries due to their higher volumetric capacity and energy density. However, they still face limitations in efficiently utilizing the active selenium. Here, we develop surface-functionalized mesoporous hollow carbon nanospheres as the selenium host. By using KOH activation, the surface of the carbon nanospheres is functionalized with hydroxyl groups, which greatly improve the utilization of selenium and facilitate the conversion of lithium selenides, leading to much higher capacities compared to ZnCl2 activation and untreated carbon nanospheres. Theory and experimental evidence suggest that surface hydroxyl groups can enhance the reduction conversion of polyselenides to selenides and facilitate the oxidation reaction of selenides to elemental selenium. In-situ and ex-situ characterization techniques provided additional confirmation of the hydroxyl groups electrochemical durability in catalyzing selenium conversion. The meticulously engineered Se cathode demonstrates a high specific capacity of 594 mA h g−1 at 0.5C, excellent rate capability of 464 mA h g−1 at 2C, and a stable cycling performance of 500 cycles at 2C with a capacity retention of 84.8 %, corresponding to an ultra-low-capacity decay rate of 0.0144 % per cycle, surpassing many reported lithium-selenium battery technologies.

Bimetallic PtAu-Decorated SnO2 Nanospheres Exhibiting Enhanced Gas Sensitivity for Ppb-Level Acetone Detection.

Acetone is a biomarker found in the expired air of patients suffering from diabetes. Therefore, early and accurate detection of its concentration in the breath of such patients is extremely important. We prepared Tin(IV) oxide (SnO2) nanospheres via hydrothermal treatment and then decorated them with bimetallic PtAu nanoparticles (NPs) employing the approach of in situ reduction. The topology, elemental composition, as well as crystal structure of the prepared materials were studied via field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The findings revealed that bimetallic PtAu-decorated SnO2 nanospheres (PtAu/SnO2) were effectively synthesized as well as PtAu NPs evenly deposited onto the surface of the SnO2 nanospheres. Pure SnO2 nanospheres and PtAu/SnO2 sensors were prepared, and their acetone gas sensitivity was explored. The findings demonstrated that in comparison to pristine SnO2 nanosphere sensors, the sensors based on PtAu/SnO2 displayed superior sensitivity to acetone of 0.166-100 ppm at 300 °C, providing a low theoretical limit of detection equal to 158 ppm. Moreover, the PtAu/SnO2 sensors showed excellent gas response (Ra/Rg = 492.3 to 100 ppm), along with fast response and recovery (14 s/13 s to 10 ppm), good linearity of correlation, excellent repeatability, long-term stability, and satisfactory selectivity at 300 °C. This improved gas sensitivity was because of the electron sensitization of the Pt NPs, the chemical sensitization of the Au NPs, as well as the synergistic effects of bimetallic PtAu. The PtAu/SnO2 sensors have considerable potential for the early diagnosis and screening of diabetes.

Facile Synthesis and Characterization of Uniform Au Nanospheres Capped by Citrate for Biomedical Applications.

We report a simple and versatile method for effectively replacing the toxic ligands, such as cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC), on the surface of Au nanospheres with different sizes by citrate. The method involves the deposition of an ultrathin shell of fresh Au in the presence of sodium citrate at an adequate concentration. After the ligand exchange process, multiple techniques are used to confirm that the surface of the resultant Au nanospheres is covered by citrate while there is no sign of aggregation. We also demonstrate the mitigation of cell toxicity after exchanging the surface-bound CTAB/CTAC with citrate, opening the door to a range of biomedical applications.

Controlling the growth of uncapped silver nanoparticles on poly methacrylic acid nanospheres: The effect of polymer’s free surface on the antimicrobial properties

In this study, the control over the growth of uncapped silver nanoparticles on the surface of poly methacrylic acid nanospheres is presented. The pH of the growth medium and the size of the polymer nanospheres were studied as parameters in relation to the antimicrobial activity of the resulting structures against Escherichia coli and Staphylococcus aureus. Adjustment of the growth medium pH has a direct effect on the number of silver nanoparticles grown on the surface of the nanospheres, while the size of the nanospheres affects the resulting silver nanoparticle size distribution. The minimum bactericidal concentration was determined to 8 and 32 μg/mL against E. coli and S. aureus respectively, whereas the antimicrobial efficiency of the resulting nanospheres was enhanced in structures with increased free surface. Hence, the contribution of the as synthesized structures to the antimicrobial activity is attributed to the polymer’s ability to form stable suspensions in the aqueous bacterial growth medium, thus promoting the dissolution of silver nanoparticles to Ag cations with antimicrobial activity.

Incorporating ZIF-8-derived ZnSe into hollow carbon nanospheres as anodes for lithium-ion batteries

Transition metal selenides (TMSs) show great potential as anode materials for lithium-ion batteries (LIBs), boasting a high theoretical capacity. Nevertheless, their practical utility faces challenges, mainly stemming from significant volume changes that lead to rapid capacity decay during charge and discharge cycles. To overcome this challenge, we present a systematic approach involving the growth of uniformly dispersed ultrafine ZnSe nanoparticles derived from ZIF-8 on the surface of hollow carbon nanospheres (ZnSe@N-HCS/700). When utilized as an anode material for LIBs, the ZnSe@N-HCS/700 electrode demonstrates exceptional electrochemical performance. Specifically, it achieves a capacity of 1299 mAh g−1 after 100 cycles at a current density of 100 mA g−1 and maintains a capacity of 614 mAh g−1 even after 1800 cycles at 2500 mA g−1. The hollow structure of the composite alleviates the volume variation of ZnSe nanoparticles during charge and discharge processes, and provides a large reactive surface area, thereby significantly enhancing lithium storage capacity. In conclusion, our strategy presents an innovative approach to synthesize negative electrode materials with unique structures for LIBs.

Fabrication of Rhenium Disulfide/Mesoporous Silica Core-Shell Nanoparticles for a pH-Responsive Drug Release and Combined Chemo-Photothermal Therapy.

A stimuli-responsive drug delivery nanocarrier with a core-shell structure combining photothermal therapy and chemotherapy for killing cancer cells was constructed in this study. The multifunctional nanocarrier ReS2@mSiO2-RhB entails an ReS2 hierarchical nanosphere coated with a fluorescent mesoporous silica shell. The three-dimensional hierarchical ReS2 nanostructure is capable of effectively absorbing near-infrared (NIR) light and converting it into heat. These ReS2 nanospheres were generated by a hydrothermal synthesis process leading to the self-assembly of few-layered ReS2 nanosheets. The mesoporous silica shell was further coated on the surface of the ReS2 nanospheres through a surfactant-templating sol-gel approach to provide accessible mesopores for drug uploading. A fluorescent dye (Rhodamine B) was covalently attached to silica precursors and incorporated during synthesis in the mesoporous silica walls toward conferring imaging capability to the nanocarrier. Doxorubicin (DOX), a known cancer drug, was used in a proof-of-concept study to assess the material's ability to function as a drug delivery carrier. While the silica pores are not capped, the drug molecule loading and release take advantage of the pH-governed electrostatic interactions between the drug and silica wall. The ReS2@mSiO2-RhB enabled a drug loading content as high as 19.83 mg/g doxorubicin. The ReS2@mSiO2-RhB-DOX nanocarrier's cumulative drug release rate at pH values that simulate physiological conditions showed significant pH responsiveness, reaching 59.8% at pH 6.8 and 98.5% and pH 5.5. The in vitro testing using HeLa cervical cancer cells proved that ReS2@mSiO2-RhB-DOX has a strong cancer eradication ability upon irradiation with an NIR laser owing to the combined drug delivery and photothermal effect. The results highlight the potential of ReS2@mSiO2-RhB nanoparticles for combined cancer therapy in the future.

Effect of silica nanospheres silanized by functional silanes on the physicochemical and mechanical properties of Bis-GMA/TEGDMA dental composite resin by photocuring synthesis

This investigation focused on the contribution of various silane blends, used as coupling agents, to the ultimate performance of dental nanocomposite dimethacrylate photocurable resins. Initially, the surface of silica nanospheres was silanized with three different silane coupling agents: γ-MPS, APTES, and OTMS, with the grafting rate serving as the index. Fourier Transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) verified the modification of nanosilica. Through orthogonal test experiments on the three silane coupling agents, the optimal modifier concentration, temperature, and time were determined. Subsequently, 15 wt% organomodified SiO2 nanospheres were incorporated into Bis-GMA/TEGDMA (70/30 by wt%) based resins via a photocuring process. Scanning electron microscopy (SEM) findings revealed a relatively vague interface between inorganic fillers and resins in the polymer composite, especially when reactive silanes like γ-MPS and their corresponding blends were used. The combination of SiO2 and γ-MPS functional silane blend provided the highest flexural properties and the lowest solubility after storing the nanocomposite in water for 1 week at 37 °C. With these methods, composite resins containing 15 wt% MPS-SiO2 nanospheres in a Bis-GMA/TEGDMA (70/30 by wt%) mixture exhibited the best comprehensive properties, making them a promising choice for achieving long-term durable restorations in clinical therapies.

Generalized Synthesis of Highly-Dispersed, Ultrafine Transition Metal Nanoparticles on Silica Spheres for Enhanced Optical Absorption.

Robust synthesis of ultrafine metal nanoparticles (ufMNPs) below 5nm with clean surfaces and strong optical absorption in the visible spectral range is challenging due to their instability originating from large surface-to-volume ratios. This work reports a general strategy involving two sequential steps: i) loading metal precursor ions onto the surface of silica nanospheres (SiOx NSs) by forming a uniform coating of metal oxyhydroxide [MOy(OH)z] through preferred surface acid-base reactions and ii) thermally reducing MOy(OH)z in forming gas at elevated temperatures to form ufMNPs evenly dispersed on the surface of SiOx NSs. The capability of this synthesis strategy is verified by loading ufMNPs of various transition metals and bimetallic combinations onto the SiOx NSs. The ufMNPs exhibit strong optical absorption enhanced by the optical scattering resonances in the SiOx NSs, which generate intense electric fields near the surface of the SiOx NSs. The SiOx NSs also support stabilizing the ufMNPs, which do not need additional organic capping reagents. The successful synthesis of SiOx-NS-supported ufMNPs with clean surfaces and enhanced optical absorption is promising for exploring the photocatalytic properties of ufMNPs.

Synthesis of the oleylamine coated mesoporous Fe3O4 nanospheres and their application towards the efficient chemical fixation of carbon dioxide

The present work reports the successful coating of Fe3O4 nanospheres with oleylamine utilizing a single-step solvothermal technique and its application to carbon dioxide's capture and chemical fixation. The existence of the pure cubic spinel phase of Fe3O4 was established by X-ray diffraction. Fourier transform infrared spectroscopy revealed vibrations corresponding to the oleylamine structure, affirming the coating of oleylamine on Fe3O4 nanospheres. X-ray photoelectron spectroscopy further confirmed the presence of oleylamine on the Fe3O4 surface, along with the constituent elements Fe and O. The nanospheres exhibited a spherical shape with an average diameter of ∼17 nm, shown by morphological investigations. Magnetic properties exhibited a Verwey transition at ∼114 K and a saturation magnetization of ∼60 emu/g. The surface area measurements revealed a pore volume of 0.0717 ccg−1 and surface area of 30.558 m2g-1. The existence of oleylamine on the surface of Fe3O4 nanospheres facilitated the capture of CO2 through chemisorption due to the amine group's high selectivity and the nanospheres' large surface area. In the presence of styrene oxide and tetra-n-hexyl ammonium bromide (THAB), the oleylamine-coated Fe3O4 nanospheres successfully converted CO2 to styrene carbonate. The magnetic core and high thermal stability of the material make it suitable for recyclability for the fixation of CO2 into products with added value. This work presents a promising approach for CO2 capture and utilization using Fe3O4 nanospheres coated with oleylamine, with potential applications in carbon capture and utilization technologies.

High-Q Tamm plasmon-like resonance in spherical Bragg microcavity resonators.

This work proposes what we believe to be a novel Tamm plasmon-like resonance supporting structure consisting of an Au/SiO2 core-shell metal nanosphere structure surrounded by a TiO2/SiO2 spherical Bragg resonator (SBR). The cavity formed between the core metal particle and the SBR supports a localized mode similar to Tamm plasmons in planar dielectric multilayers. Theoretical simulations reveal a sharp absorption peak in the SBR bandgap region, associated with this mode, together with strong local field enhancement. We studied the modification of a dipolar electric emitter's radiative and non-radiative decay rates in this resonant structure, resulting in a quantum efficiency of ∼90% for a dipole at a distance of r=60n m from the Au nanosphere surface. A 30-layer metal-SBR Tamm plasmon-like resonant supporting structure results in a Q up to ∼103. The Tamm plasmon-like mode is affected by the Bragg wavelength and the number of layers of the SBR, and the thickness of the spacer cavity layer. These results will open a new avenue for generating high-Q Tamm plasmon-like modes for switches, optical logic computing devices, and nonlinear applications.