One-pot Hydrothermal Route Research Articles

Dual-Signal Triple-Mode Optical Sensing Platform for Assisting in the Diagnosis of Kidney Disorders.

As known biomarkers of kidney diseases, N-acetyl-β-d-glucosaminidase (NAG) and β-galactosidase (β-GAL) are of great importance for the diagnosis and treatment of diseases. The feasibility of using multiplex sensing methods to simultaneously report the outcome of the two enzymes in the same sample is even more alluring. Herein, we establish a simple sensing platform for the concurrent detection of NAG and β-GAL using silicon nanoparticles (SiNPs) as a fluorescent indicator synthesized by a one-pot hydrothermal route. p-Nitrophenol (PNP), as a common enzymatic hydrolysis product of the two enzymes, led to the attenuation of fluorometric signal caused by the inner filter effect on SiNPs, the enhancement of colorimetric signal due to the increase of intensity of the characteristic absorption peak at around 400 nm with increasing reaction time, and the changes of RGB values of images obtained through a color recognition application on a smartphone. The fluorometric/colorimetric approach combined with the smartphone-assisted RGB mode was able to detect NAG and β-GAL with good linear response. Applying this optical sensing platform to clinical urine samples, we found that the two indicators in healthy individuals and patients (glomerulonephritis) with kidney diseases were significantly different. By expanding to other renal lesion-related specimens, this tool may show great potentials in clinical diagnosis and visual inspection.

Direct decoration of commercial cotton fabrics by binary nickel-cobalt metal-organic frameworks for flexible glucose sensing in next-generation wearable sensors

Having a prime significance in diagonsing and predicting the dangerous symptoms of chronic diseases in the early stages, special attention has been drawn by wearable glucose-sensing platforms in recent years. Herein, modified commercial cotton fabrics, decorated with binary Ni–Co metal-organic frameworks (NC-MOFs) through a one-pot scalable hydrothermal route, were directly utilized as flexible electrodes for non-enzymatic glucose amperometric sensing. Glucose sensitivities of 105.2 μA mM−1 cm−2 and 23 μA mM−1 cm−2 were acheived within two distinct linear dynamic ranges of 0.04–3.13 mM and 3.63–8.28 mM, respectively. Receiving benefits from a remarkable glucose sensitivity behavior in co-existence of iso-structures and interferences, rapid response (4.2 s), and remarkable reproducibility and repeatability, NC-MOF-modified cotton fabric electrodes are imensilly promising for developing high-performance wearable glucose sensing platfroms. The sensing performance of fabricated electrodes was further investigated in human blood serum and saliva.

Flower-like and nanorods ZnO deposited on rGO as efficient photocatalysts for removal of polychlorinated biphenyls (PCBs)

PCBs were used for several decades as coolants, lubricants in transformers, plasticizers, and dielectric fluids, being highly carcinogenic and representing a severe environmental problem in soil and water. Pure and modified TiO2 has been the most studied photocatalyst looking to degrade PCBs into less toxic products. Lately, ZnO-graphene composites have played an essential role in the photocatalytic degradation of various toxic organic compounds. In this work, ZnO nanostructures were coupled with reduced graphene oxide (ZnO-rGO) via a one-pot microwave-assisted hydrothermal route. As a result, the composites exhibited improved photocatalytic performance for PCBs degradation compared to ZnO nanoparticles. Thus, this research provides an in-situ method to grow different morphologies of ZnO on rGO.

Self-promoted Nickel-chalcogenide Nanostructures: A Novel Electrochemical Supercapacitor Device-design Strategy

Self-grown nickel-chalcogenides viz ., sulphide (NiS), selenide (NiSe), and sulfoselenide (NiSSe) nanostructures of the aligned nanorod, nanosheet, and nanobud-type morphologies are successfully synthesized through one-pot hydrothermal synthesis route on 3-D nickel-foam (NiF). The precursors of sulfur and selenium break down into S 2− and Se 2− ions, which then react with oxidized Ni 2+ ions on the surface of pure NiF to make NiS, NiSe, and NiSSe superstructures. The structural, morphological, and chemical states of as-grown Ni-based electrodes are monitored through various measurement tools. The as-obtained Ni-based NiS, NiSe and NiSSe electrode materials of various morphologies endow specific capacitances and specific capacities, at a current density of 3 A g −1 , of 1683.5 F g −1 , 1563.6 F g −1 , and 3314.9 Fg −1 and 187.05, 173.86, and 368.32 mAh g −1 respectively, in a three-electrode system containing 1.0 M KOH electrolyte solution. The NiSSe demonstrating the highest specific capacitance and outstanding chemical stability compared to other electrode materials might be due to the synergistic effect to improve overall electrochemical activity. In addition, the NiSSe electrode is chemically stable and mechanically robust as it doesn't detach from the conductive NiF substrate even at a high current density. Consequently, the as-designed NiSSe//NiSSe symmetric supercapacitor assembly divulges1658.6 Wkg −1 power density and 19.21 Whkg −1 energy density with the cycling stability of 93.48%. Connecting two cells in a series a panel “CNED” composed of nearly forty-two LEDs is ignited with high light intensity, adducing the practical importance of mixed metal chalcogenide electrode material in the energy storage sector.

Efficient and controllable synthesis of zeolite Beta nanospheres and hollow-boxes using a temperature-sensitive bifunctional additive

Zeolite Beta nanospheres and hollow-boxes are successfully obtained through a simple one-pot hydrothermal crystallization route, using tetraethylammonium hydroxide (TEAOH) as the structure-directing agent (SDA) assisted with a temperature-sensitive bifunctional additive N-methyl-2-pyrrolidone (NMP). The influences of crystallization temperature, Si/Al ratio, and TEAOH content on the synthesis and physicochemical properties of zeolite Beta as well as the formation of hollow structure are investigated in detail. It reveals that the role of NMP changes from “crystallization promoter” (CP) to “hollow-directing agent” (HDA). And the acceleration effect of NMP decreases upon the crystallization temperature (120–160 °C) due to the decomposition of TEAOH. Meanwhile, high synthesis temperature (≥180 °C), high Si/Al ratio (≥30), and low TEAOH content (TEAOH/SiO2 ≤ 0.2) may lead to the formation of undesired zeolites ZSM-5 and/or ZSM-12. The obtained Beta nanosphere and hollow-box catalysts exhibit excellent catalytic activity in the degradation of low-density polyethylene (LDPE) due to their high external surface area and acid density.

Electropositive far-ultraviolet carbon nanoparticles-based photoluminescent photoinduced-electron transfer sensor for sodium dodecyl sulfate and sodium lauryl sulfonate detection

Unrestrained use of sodium dodecyl sulfate (SDS) and sodium lauryl sulfonate (SLS) in industry, agriculture and household are causing its subsequent accumulation in waterways, which can cause the adverse effect on various living organisms, especially aquatic organisms. Therefore, an efficient and rapid technique to detect SDS and SLS in the environment is urgently demanded. Herein, a novel far-ultraviolet emission carbon nanoparticles (FCNPs, quantum yield of ∼15.47%) with positive charges was synthesized by one-pot simple hydrothermal route using 5-hydroxytryptamine as the precursor, and applied to the detection of SDS and SLS. When the exposure to SDS and SLS, the FCNPs displayed anionic detergent-sensitive fluorescent quenching. The mechanism was proved to be that enrichment-positive charge of –NH3+ groups can strongly combine with negatively charged SDS/SLS molecules through electrostatic adsorption, resulting in luminescent quenching of FCNPs via photoinduced-electron transfer mechanism. By using this sensing platform, there are two good linear relationships between the quenching degree of the FCNPs and the concentrations of SDS and SLS in the range of 5.0 nM–50 μM and 2.5 nM to 50 μM with almost the same LOD of ∼2.5 nM, respectively. Moreover, this sensing platform has been successfully applied to detect the SDS and SLS in real domestic wastewater samples. Therefore, the electropositive luminescent FCNPs might possess enormously potential utilization in the detection of anionic detergent for environmental protection.

High-Efficiency Utilization of Waste Tobacco Stems to Synthesize Novel Biomass-Based Carbon Dots for Precise Detection of Tetracycline Antibiotic Residues.

Recycling waste biomass into valuable products (e.g., nanomaterials) is of considerable theoretical and practical significance to achieve future sustainable development. Here, we propose a one-pot hydrothermal synthesis route to convert waste tobacco stems into biomass-based N, S-codoped carbon dots (C−dots) with the assistance of carbon black. Unlike most of the previously reported luminescent C−dots, these biomass-based C−dots showed a satisfactory stability, as well as an excitation-independent fluorescence emission at ~520 nm. Furthermore, they demonstrated a pH-dependent fluorescence emission ability, offering a scaffold to design pH-responsive assays. Moreover, these as-synthesized biomass-based C−dots exhibited a fluorescence response ability toward tetracycline antibiotics (TCs, e.g., TC, CTC, and OTC) through the inner filter effect (IFE), thereby allowing for the establishment a smart analytical platform to sensitively and selectively monitor residual TCs in real environmental water samples. In this study, we explored the conversion of waste tobacco stems into sustainable biomass-based C−dots to develop simple, efficient, label-free, reliable, low-cost, and eco-friendly analytical platforms for environmental pollution traceability analysis, which might provide a novel insight to resolve the ecological and environmental issues derived from waste tobacco stems.

Tailorable Formation of Hierarchical Structure Silica (HMS) and Its Application in Hydrogen Production

Relentless endeavors have been committed to seeking simple structure-directing agents for synthesizing hierarchical mesoporous silica (HMS) materials but remaining challenges. In this contribution, we offered an improved one-pot hydrothermal route to prepare HMS materials using a single non-ionic triblock copolymer (F127) structure-directing agent under a mild polycarboxylic (citric acid) mediated condition. Via studies of key synthetic parameters including acid concentration, crystallization temperature and aging time, it was found that citric acid medium presents an important bridging effect under the optimal concentration from 0.018 M (pH = 2.57) to 1.82 M (pH = 1.09), contributing to the self-assemblage of partially protonated non-ionic triblock copolymer and tetraethyl orthosilicate (TEOS) into a high-quality multistage structure of silica materials. The specific surface area (SSA) of HMS shows a volcanic trend and is closely associated with the concentration of citric acid while the highest SSA of 739.9 m2/g can be achieved at the citric concentration of 0.28 M. Moreover, the as-synthesized HMS-CTA supported Ni/CeO2 catalysts indicate an excellent production of hydrogen through dry reforming of methane (DRM) reaction over 172 h stability. The improved, facile synthesis strategy under polycarboxylic medium displays an expanded perspective for synthesizing other mesoporous materials in a wide range of applications such as catalytic material carriers and drug inhibitors.

Fabrication of rectangular zirconium dioxide nanoparticles decorated reduced graphene oxide nanocomposites as thin and high-efficiency electromagnetic wave absorbers

The design and development of graphene-based composites with strong absorption, wide bandwidth and thin thickness remain a great challenge in the field of electromagnetic (EM) absorption. In this work, reduced graphene oxide/zirconium dioxide (RGO/ZrO2) nanocomposites were synthesized by a one-pot hydrothermal route. Results of micromorphology analysis showed that the attained nanocomposites had a good dispersion of particles, and a large number of rectangular ZrO2 nanoparticles were almost uniformly distributed on the crumpled surfaces of thinly flake-like RGO. Moreover, the EM absorbing properties of as-prepared binary nanocomposites could be regulated by adjusting the contents of RGO and matching thicknesses. It was noteworthy that the attained RGO/ZrO2 nanocomposite with the content of RGO of 22.3 wt% and a filler loading ratio of 45 wt% presented the best EM absorption performance, i.e. the minimum reflection loss reached up to −56.9 dB at the frequency of 13.4 GHz with a matching thickness of 2.02 mm, and the broadest effective absorption bandwidth achieved 5.5 GHz under a very thin thickness of 1.85 mm. Furthermore, the possible EM loss mechanism had been proposed. These results could provide a reference for the fabrication of RGO-based composites as thin and high-efficient EM wave absorbers.

Facile construction of three-dimensional porous netlike reduced graphene oxide/zinc oxide composite aerogels as the lightweight, flame retardant, compression resilience and high-performance electromagnetic wave absorbers

In this work, reduced graphene oxide/zinc oxide (RGO/ZnO) composite aerogels were constructed through a one-pot hydrothermal route. Results manifested that the composite aerogels had the extremely low density and a unique three-dimensional porous network structure, and lots of ZnO particles were almost homogeneously loaded on the rippled surfaces of lamellar RGO. Moreover, the micromorphology and electromagnetic absorbing properties of composite aerogels were facilely regulated by changing the additive amounts of sodium citrate. Notably, the optimal minimum reflection loss reached −79.1 dB at a matching thickness of 2.49 mm and maximum effective absorption bandwidth achieved 7.7 GHz under a thickness of 1.97 mm and filling ratio of 20.0 wt%. Furthermore, the attained composite aerogels presented excellent flame retardant and compression resilience properties. Additionally, the possible electromagnetic dissipation mechanism was proposed. This work provided a reference for the design and preparation of RGO-based dielectric composites as the multifunctional electromagnetic wave absorbers.

One-pot hydrothermal synthesis of a double Z-scheme g-C3N4/AgI/β-AgVO3 ternary nanocomposite for efficient degradation of organic pollutants and DPC-Cr(VI) complex under visible-light irradiation.

The Z-scheme photocatalytic system provides a promising way to achieve significant photodegradation efficiency. The work embodied here describes the synthesis of highly efficient double Z-scheme g-C3N4/AgI/β-AgVO3 (g-CNAB) ternary nanocomposite using a one-pot hydrothermal route. The optical properties, phase structure, and morphology of the synthesized samples were investigated using UV-visible diffuse-reflectance spectroscopy (UV-Vis DRS), X-ray diffraction, and scanning electron microscopy, respectively. The transmission electron microscopy investigation revealed that synthesized composite material represents close interfacial interactions. X-ray photoelectron spectroscopy analysis confirms the presence of all the elements in the synthesized ternary nanocomposite materials. The photocatalytic performance of as-prepared photocatalysts has been systematically investigated using the photodegradation of a variety of pollutants, including Rhodamine B, Ciprofloxacin, and 1,5-diphenylcarbazide-Cr(VI) [DPC-Cr(VI)] complex under visible-light irradiation. Among all synthesized materials, such as g-C3N4, AgI, β-AgVO3, and ternary nanocomposites with varying loading of β-AgVO3 [g-CNAB(0.5, 1.0, 1.5, 2.0)], the photocatalyst g-CNAB(1.5) nanocomposite achieved a remarkably high photocatalytic efficiency. The quenching impact of several scavengers revealed that reactive species such as superoxide anion radical (O2·-) and hydroxyl radical (·OH) are significant in the degradation of various contaminants. Based on the characterization and application, a plausible photocatalytic mechanism has been sketched out to determine the reaction pathways involved in the degradation of pollutants present in the aqueous medium.

Hydrothermal Synthesis of Spinel-Perovskite Li-Mn-Fe-Si Nanocomposites for Electrochemical Hydrogen Storage.

Owing to the extensive requirement for renewable energy sources such as hydrogen, great efforts are being devoted to optimizing the active ingredients for advanced hydrogen storage. In this regard, an ideal spinel-perovskite nanocomposite based on Li-Mn-Fe-Si materials was successfully fabricated via a one-pot hydrothermal route to store hydrogen electrochemically. To optimize both the phase composition and morphological features of nanostructures, the reaction was engineered under different conditions. Li-Mn-Fe-Si spinel-perovskite diphase structures were created with diverse shapes of polyhedral-shaped bulk particles, nanoparticles, nanoplates, and hierarchical structures. The alteration of multiple factors such as hydrothermal reaction time, temperature, polymeric surfactant type, and calcination temperature was surveyed to achieve the optimized size and morphology of the nanoproducts to be obtained. The morphological changes, structural regulations, porosity, and magnetic properties of the nanosized products were studied via field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray powder diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET), and vibrating sample magnetometer (VSM) analyses. In addition, the electrochemistry features of the Li0.66Mn1.85Fe0.43O4/Fe2.57Si0.43O4/FeSiO3 (LMFO/FSO) nanocomposites were introduced on the basis of discharge capacity, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry(CV) methods in an alkaline electrolyte. The discharge capacity of the LMFO/FSO nanostructures with a nanoplate-like morphology as an optimal sample was calculated to be 910 mAh/g after 15 cycles at a constant current of 1 mA. The electrochemistry results confirm that the hydrogen storage capability of nanoplate composites is higher than those of other morphologies due to their superior surface area and faster electron transfer. Besides, this proposed strategy could simultaneously manipulate the architectural and compositional complexities to generate a superior electrochemical behavior in energy storage devices.

Supercapacitive performance of Fe-doped nickel molybdate/rGO hybrids: The effect of rGO

Hydrated nickel molybdate (HNMO) is considered one of the fascinating materials for various applications due to its porous structure, low synthesis cost, good specific surface area, and abundant features. Nonetheless, the primal HNMO suffers from an inferior electrical conductivity, hence a poor supercapacitive property. For solving this drawback, we synthesize Fe-doped HNMO/rGO rod-like nanostructure hybrids (FNMG) using a one-pot hydrothermal route where our special emphasis is placed on investigating their supercapacitive performance. The powders with different rGO contents were studied and compared. Considering the data obtained from FTIR and Raman spectroscopy, XRD, FESEM, and HRTEM, rGO is firmly linked to Fe-doped HNMO via electrostatic interaction, exhibiting a preferable supercapacitive ability among the various compounds of the HNMO family. The supercapacitive properties of the electrodes were studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) tests. Among the mentioned electrodes, the one containing 15 mg mL−1 graphene oxide (GO) suspension (FNMG15) possesses the best electrochemical performance with a capacity of 1189 F g−1 at 1 A g−1 current density, and in a 2 M KOH electrolyte, notably higher than that with 20 mg mL−1 GO (around 19.5%), and 5 mg mL−1 GO (around 44%). Meanwhile, cyclic stability and rate performance of the FNMG15 sample were reached to 86% and 71%, respectively. Eventually, a two-electrode asymmetric energy storage device (FNMG15//AC) was fabricated. It shows a specific capacitance of 182.7 F g−1, a maximum energy density of 65.03 Wh kg−1 at a power density of 686.5 W kg−1, and cycling stability of 83.2% after 1000 cycles. The resulting data imply that the FNMG15 has an excellent capability for electrochemical energy storage devices.

A novel ratiometric fluorescent probe for detection of l-glutamic acid based on dual-emission carbon dots

In this article, we report for the first time the use of a dual-emission carbon dots (CDs) with orange-yellow fluorescence for the detection of l-glutamic acid (L-Glu). The CDs was synthesized through a facile strategy of one-pot hydrothermal route using o-phenylenediamine (oPD) and oxalic acid. The CDs exhibit two fluorescence emission peaks around 453 nm and 560 nm when the excitation wavelength is at 390 nm. In the existence of L-Glu the fluorescence at 560 nm was decreased, whereas the fluorescence at 453 nm was constant. The fluorescence intensity ratio at 560 nm and 453 nm (F560/F453) expressed two great linear relationships in the L-Glu concentration range from 0 to 200 μM and 200–400 μM, respectively, with a detection limit (LOD) of about 0.085 μM. In addition, it was used to analyze L-Glu in fetal bovine serum samples successfully, which recoveries were ranging from 97.07 to 103.7%. Those results demonstrate CDs can be further explored in biomedicine studies.

One Pot Synthesis of Lanthanum Doped Cobalt Selenate Electrocatalyst for Oxygen Evolution Reaction (OER)

There is a continuous demand and burning of limited fossil fuel prompted the urgent need to develop renewable, abundant, and clean energy source. There- fore, for solving the energy crisis, the production of green hydrogen by elec- trochemical water splitting plays a vital role in achieving this goal. But, this electrochemical energy production process is kinetically sluggish due to multi- electron transfer reactions Therefore, the development of an efficient inexpen- sive catalyst towards OER have been required to accelerate the rate of oxy- gen evolution. We effectively designed and synthesized sheet-like morphology of lanthanum doped cobalt selenate through the one-pot hydrothermal route. The synthesized material is confirmed by different techniques. Herein prepared sheet-like La doped CoSe2O5 material is employed as an efficient electrocata- lyst towards OER in alkaline medium. This electrocatalyst show the low Over- potential and the low the Tafel slop value. Also successfully doped with the rare earth metal it show the large exchange current density and the active sites.

TiO2 nanorods decorated on RGO sheet for an excellent energy storage performance

Herein, we report nanocomposite of titanium dioxide (TiO2) nanorods decorated reduced graphene oxide (TiO2/RGO) nanocomposite prepared using the simple, one-pot hydrothermal route for electrode material in supercapacitor applications. A systematic comparison study was carried out for the TiO2 nanorods coated on graphite foil in presence of alkaline media 3 M KOH, NaCl, and Na2SO4 using the three-electrode method. The TiO2/RGO composite shows an excellent specific capacitance (Csp) of 330 Fg-1 at the discharge current density 0.5 Ag-1 in presence of 3 M KOH electrolyte solution. The obtained highest specific capacitance values in order by various electrolytes are observed as KOH > NaCl > Na2SO4. The long-term cycle stability of charge and discharge cycle at current density 0.5 Ag-1 over 1000 cycles and only 8% decay in the specific capacitance of TiO2/RGO nanocomposite was observed in 3 M KOH electrolyte. The improved electrochemical performance TiO2/RGOcomposite in presence of KOH electrolyte is shown to be the most suitable electrode for the supercapacitors.

Enhanced α-Mn2O3 nanorods synthesized by one-pot hydrothermal route for supercapacitors

Enhanced α-Mn2O3 nanorods synthesized by one-pot hydrothermal route for supercapacitors

Synthesis and antimicrobial activity of vancomycin–conjugated zinc coordination polymer nanoparticles against methicillin-resistant staphylococcusaureus

Due to the overuse of antimicrobial drugs, Methicillin-resistant Staphylococcus aureus (MRSA) has caused a serious burden worldwide. Herein, we report a novel one-pot hydrothermal route to synthesize a vancomycin-encapsulated Zn-BTC-coordination polymer. FTIR and PXRD confirmed the composites and crystal structure of coordination polymer. The VAC-Zn-BTC-coordination polymer had a mean diameter, polydispersity index (PDI), zeta potential, and encapsulation efficiency of 59.6 ± 2.98 nm, 0.295 ± 0.0147, −11 ±-0.55 mV and 68.24 ± 3.412%, respectively at physiological pH. The safety of MTT in vitro in Human embryonic kidney 293 cells (HEK-293), adenocarcinomic human alveolar basal epithelial cells (A-549), and Michigan Cancer Foundation-7 (MCF-7) cell lines and the hemolytic assay of VAC-Zn-BTC-coordination polymer was evaluated. The in vitro results of the MTT assay were revealed to be safe in all three cell lines and non-hemolytic, thus indicating their biosafety. Molecular dynamics simulations (MDS) showed that higher binding and interaction energies were seen. The VAC release from the VAC-Zn-BTC-coordination polymer was slower than the powder VAC after 48 h. The VAC-Zn-BTC-coordination polymer revealed a lower MIC value of 1.02 μg/mL against MRSA with a 10-fold antimicrobial enhancement. The bactericidal time-kill kinetics assay showed that VAC-Zn-BTC-coordination polymer combinations showed good bactericidal effects over 24 h compared to bare VAC powder. These findings suggest that VAC-Zn-BTC-coordination polymer could be used as excellent potential for the improvement and management of bacterial contagions instigated by MRSA.

Controllable doping of Fe atoms into MoS2 nanosheets towards peroxidase-like nanozyme with enhanced catalysis for colorimetric analysis of glucose

MoS2 nanosheets were doped with Fe elements simply via the one-pot hydrothermal route resulting in the peroxidase-like nanozymes with dramatically enhanced catalysis. It was discovered that the resulted Fe-MoS2 could display controllable catalysis activities depending on the Mo-to-Fe molar ratios, among which the highest one was achieved at 3/1 with catalysis efficiency over three folds higher than that of pristine MoS2. The greatly improved catalysis performances of Fe-MoS2 nanozyme are thought to be resulted from the synergistic effects of the doped Fe atom and Mo-S sites. On the one hand, herein, the Fe sites might serve as the electron transferring mediators to facilitate the peroxidase-like catalytic reactions, as confirmed by the cytochrome C-based electron transportation experiments. On the other hand, the Mo-S sites might conduct the catalytic behavior of Fenton-like reactions, as revealed by the hydroxyl radicals-capturing experiments. Furthermore, the feasibility of practical applications for the developed Fe-MoS2 nanozyme based colorimetric methods was demonstrated for glucose in blood sample. Importantly, an insight can be thereby obtained into the design of different nanozymes with enhanced catalysis designed by doping heteroatoms like Fe, promising for the catalysis-based applications in the biomedical analysis, food safety, and environmental monitoring fields.

Encapsulation of ultra-small Cu–Fe into ZSM-5 zeolites for NH3-SCR with broad reaction-temperature ranges

A direct hydrothermal synthesis strategy is developed to prepare the Cu–Fe-ZSM-5 zeolites by using the ethylenediaminetetraacetic acid disodium dihydrate (EDTA-2Na·2H2O) chelated Cu2+ and Fe3+ precursors as metal sources. During the crystallization, the metal chelates were spontaneously embedded into the ZSM-5 crystals and subsequently transformed to the zeolites encapsulated copper and iron species after removing the chelating agent via the high-temperature calcination. Rigorous characterizations indicate that the resulted Cu2+/Cu+ and Fe3+/Fe2+ species are formed ultra-small nano-composites with an average diameter of ∼2.2 nm and highly dispersed in the ZSM-5 zeolite crystals. The acidity of the ZSM-5 zeolites is subtly modulated by the encapsulated Cu–Fe nano-composite. As expected, the as-prepared Cu–Fe-ZSM-5 exhibits outstanding catalytic performance for the selective catalytic reduction of NOx with ammonia (NH3-SCR) in the broad reaction temperature ranges of 220–480 °C, which is much better than the Cu–Fe/ZSM-5 prepared with the conventional wetness impregnation method. Furthermore, the resultant zeolites show high stability and good tolerance to H2O and SO2, and it is very competitive for practical application to eliminate NOx. The developed one-pot hydrothermal synthesis route by using EDTA-2Na·2H2O as chelating agent is very convenient and easily reproducible, providing a general guideline to design and fabricate the superior transition metal modified zeolite catalysts for NH3-SCR and the related reactions.