One-pot Hydrothermal Synthesis Research Articles

Facile one-pot hydrothermal synthesis of reticulated porous tobermorite for fast phosphorus recovery

Phosphorus, a depletable resource in nature, has been constantly consumed. Its recovery still remains difficult to be solved. Tobermorite (Ca5Si6O16(OH)2) with chemical stability is an efficient adsorbent for phosphorus. Herein, the reticulated porous tobermorite (CSH) was successfully synthesized through a facile one-step hydrothermal process and its adsorption performance for phosphorus was evaluated. The adsorption reached the equilibrium within 5 min. The kinetic study demonstrated that the adsorption followed the pseudo-second-order model, indicating the adsorption involved the chemisorption. The adsorption perfectly fitted the Langmuir isotherm. The calculated maximum adsorption capacity is 152.46 mg·g−1 at room temperature. Its excellent adsorption performance for phosphorus is attributed to its reticulated porous structure and larger specific surface area. The adsorption is mainly affected by the electrostatic interaction and the releasing ability of OH- and Ca2+ from the CSH. Reticulated porous CSH is a potential efficient adsorbent for phosphorus recovery owing to its facile synthesis, fast adsorption rate, high adsorption capacity and excellent reusability, which provide a feasible alternative for phosphorus recovery.

Activated Carbon Supported Ni-Co Layered Double Hydroxides Nanowires: An Effective and Low-Cost Electrocatalyst for Ethanol Electro-Oxidation in Alkaline Media

Developing nanostructured electrocatalysts by utilizing low-cost, non-noble metals with good activity and stability to replace noble metals such as Pt and Pd has gained significant interest in the area of sustainable energy production technologies. To that effect, we adopted a facile synthesis route to synthesize NiCo-LDH (layered double hydroxides) nanowires with activated carbon (AC) as support using a one-pot hydrothermal synthesis method. The role of AC on the activity of NiCo-LDH catalyst was studied. The activity of the electrocatalysts was characterized using Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), and Chronoamperometry (CA) techniques. The NiCo-LDH/AC, with Ni:Co molar ratio of 1:2, exhibited a good electrocatalytic activity of 12.5 mA cm−2 at 1.1 V vs SCE (saturated calomel electrode) at a scan rate of 50 mV s−1 and retained a remarkable cyclic stability of 74.4% even after 200 cycles in 0.1 M NaOH and 1 M EtOH. The better electrocatalytic activity of NiCo-LDH/AC catalyst can be ascribed to the presence of extremely active sites and porous structures as well as a good electron transfer conductivity of AC. The facile synthesis of NiCo-LDH/AC and its attractive performance highlights its potential application as an anodic electrocatalyst in direct ethanol fuel cells (DEFCs).

Functionalized MoS2: circular economy SERS substrate for label-free detection of bilirubin in clinical diagnosis.

A one-pot hydrothermal synthesis of Fe-doped MoS2 nanoflowers (Fe-MoS2 NFs) has been developed as a surface-enhanced Raman spectroscopy (SERS) substrate. The Fe-MoS2 NFs display high reproducibility, stability, and recyclability, which is beneficial for the development of the sustainable ecological environment. The SERS substrate provides a high enhancement factor of 105, which can be ascribed to the inducing defects by doping Fe that can improve the charge transfer between probe molecules and MoS2. TheFe-MoS2 NFshave beenused to detect bilirubin in serum. The Fe-MoS2 NF SERS substrate exhibits a linear detection range from 10-3 to 10-9M with a low limit of detection (LOD) of 10-8M. Thesubstrate displays an excellent selectivity to bilirubin in the presence of other potentiallyinterfering molecules (dextrose and phosphate). These results providea novel concept to synthesize ultra-sensitive SERS substrates and open up a wide range of possibilities for new applications of MoS2 in clinical diagnosis.

Orange Peel Biomass-derived Carbon Supported Cu Electrocatalysts Active in the CO2 -Reduction to Formic Acid.

We report a green, wet chemistry approach towards the production of C-supported Cu electrocatalysts active in the CO2 reduction to formic acid. We use citrus peels as a C support precursor and as a source of reducing agents for the Cu cations. We show that orange peel is a suitable starting material compared to lemon peel for the one-pot hydrothermal synthesis of Cu nanostructures affording better Cu dispersion as well as productivity and selectivity towards formic acid. We rationalize this finding in terms of the beneficial chemical composition of the orange peel, which favors both the reduction of the Cu precursor as well as the carbon matrix. This work demonstrates new viable opportunities for the reuse of citrus waste on a rational basis.

Ultrasonic-assisted synthesis of porous S-doped carbon nitride ribbons for photocatalytic reduction of CO2.

A series of porous S-doped carbon nitride ribbons (PSCN) were prepared by one-pot hydrothermal and sonochemical synthesis techniques. The morphologies and nanostructures of the catalysts were characterized by SEM, XRD and IR, which confirmed the pristine graphitic structures of carbon nitrides retained in the products. Due to sonication treatment, PSCN has porous structures in the thin ribbon and larger specific surface areas (PSCN 43.5 m2/g, SCN 26.6 m2/g and GCN 6.5 m2/g). XPS and elemental mappings verified that sulfur atoms were successfully introduced into the carbon nitride framework. Diffuse reflectance spectroscopy (DRS) results showed S-doping in the carbon nitride reduced the bandgap energy and enhanced their capability of the utilization of visible light, which contributed to higher photo-generated current. Photoluminescence (PL) analysis indicates the recombination of photogenerated carriers was suppressed in PSCN. Moreover, the photocatalytic performance showed that S-doping and porous and thin ribbon nanostructures may effectively boost the CO2 reduction rate (to as much as 5.8 times of GCN) when illuminated byvisible light (>420 nm) without the need of sacrificial materials. The preliminary mechanisms of the formation of PSCN and its applications in photocatalytic CO2 reduction are proposed. It highlights the potential of the current technique to produce effective, nonmetal-doped carbon nitride photocatalysts.

Facile one-pot hydrothermal synthesis of a zinc oxide/curcumin nanocomposite with enhanced toxic activity against breast cancer cells.

Zinc oxide/Curcumin (Zn(CUR)O) nanocomposites were prepared via hydrothermal treatment of Zn(NO3)2 in the presence of hexamethylenetetramine as a stabilizing agent and CUR as a bioactive element. Three ZnO : CUR ratios were investigated, namely 57 : 43 (Zn(CUR)O-A), 60 : 40 (Zn(CUR)O-B) and 81 : 19 (Zn(CUR)O-C), as assessed by thermogravimetric analyses, with an average hydrodynamic diameter of nanoaggregates in the range of 223 to 361 nm. The interaction of CUR with ZnO via hydroxyl and ketoenol groups (as proved by X-ray photoelectron spectroscopy analyses) was found to significantly modify the key properties of ZnO nanoparticles with the obtainment of a bilobed shape (as shown by scanning electron microscopy), and influenced the growth process of the composite nanoparticles as indicated by the varying particle sizes determined by powder X-ray diffraction. The efficacy of Zn(CUR)O as anticancer agents was evaluated on MCF-7 and MDA-MB-231 cancer cells, obtaining a synergistic activity with a cell viability depending on the CUR amount within the nanocomposite. Finally, the determination of reactive oxygen species production in the presence of Zn(CUR)O was used as a preliminary evaluation of the mechanism of action of the nanocomposites.

One-pot hydrothermal synthesis of orientated delafossite CuFeO2 films from a mildly acidic solution on substrates

The hydrothermal deposition of delafossite CuFeO2 films on substrates is achieved by using a mildly acidic solution. The CuFeO2 obtained has a well-faceted surface morphology and a [110] preferred growth orientation.

Urethane functions can reduce metal salts under hydrothermal conditions: synthesis of noble metal nanoparticles on flexible sponges applied in semi-automated organic reduction.

We report an additive-free one-pot hydrothermal synthesis of Au, Ag, Pd, and alloy AuPd nanoparticles (NPs) anchored on commercial polyurethane (PU) foams. While unable to reduce the precursor metal salts at room temperature, PU is able to serve as a reducing agent under hydrothermal conditions. The resulting NP@PU sponge materials perform comparably to reported state-of-the-art reduction catalysts, and are additionally very well suited for use in semi-automated synthesis: the NP anchoring is strong enough and the support flexible enough to be used as a 'catalytic sponge' that can be manipulated with a robotic arm, i.e., be repeatedly dipped into and drawn out of solutions, wrung out, and re-soaked.

One-pot hydrothermal synthesis of metal-doped carbon dot nanozymes using protein cages as precursors.

Metal-doped carbon dots represent a new class of promising nanomaterials with enzyme-like activity, whose properties such as fluorescence properties and enzyme-like activity are determined by the precursors and the conditions used to prepare them. Nowadays, the synthesis of carbon dots using naturally occurring precursors has attracted increasing attention. Here, using metal-loaded horse spleen ferritin as a precursor, we report a facile one-pot hydrothermal strategy to synthesise metal-doped fluorescent carbon dots with enzyme-like activity. The as-prepared metal-doped carbon dots exhibit high water solubility, uniform size distribution, and good fluorescence. In particular, the Fe-doped carbon dots exhibit prominent oxidoreductase catalytic activities, including peroxidase-like, oxidase-like, catalase-like, and superoxide dismutase-like activities. This study provides a green synthetic strategy for developing metal-doped carbon dots with enzymatic catalytic activity.

CuCoO2/CuO heterostructure: understanding the role of band alignment in selective catalysis for overall water splitting

Employing a facile one-pot hydrothermal synthesis approach, in this work, we achieved the successful synthesis of a CuCoO2/CuO heterostructure, which was characterized by an atomic-scale intimately bonded interface.

One-pot hydrothermal synthesis of a carbon quantum dot/CaFe2O4 hybrid nanocomposite for carcinogenic Congo red dye degradation.

Semiconductor materials show a restricted degradation response to organic pollutants due to limited photocatalytic activity under visible light. Therefore, researchers have devoted much attention to novel and effective nanocomposite materials. For the first time, herein, a novel nano-sized semiconductor calcium ferrite modified by carbon quantum dots (CaFe2O4/CQDs) photocatalyst is fabricated via simple hydrothermal treatment for the degradation of aromatic dye using a visible light source. The crystalline nature, structure, morphology, and optical parameters of each of the synthesized materials were investigated using X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV-visible spectroscopy. The nanocomposite exhibits excellent photocatalytic performance (90% degradation) against Congo red (CR) dye. In addition, a mechanism for CaFe2O4/CQDs improving photocatalytic performance has been proposed. The CQDs in the CaFe2O4/CQD nanocomposite are considered to act as an electron pool and transporter, as well as a strong energy transfer material, during photocatalysis. CaFe2O4/CQDs appear to be a promising and cost-effective nanocomposite for dye-contaminated water purification, according to the findings of this study.

A novel removable template method for the preparation of persistent luminescence nanoparticles with biocompatible size and high intensity.

NIR persistent luminescence nanoparticles (PLNPs) are appealing for bio-imaging because of the properties of extremely low autofluorescence interference and deep tissue penetrating ability. However, current preparation methods can hardly simultaneously endow PLNPs with nano-scale size, long persistent luminescence (PersL) life, and high luminescence intensity, which can hardly meet the requirements of bio-imaging. Herein, we report a new synthetic route to nano-sized chromium-doped zinc gallate (ZGC) via a removable MOF template, i.e., one-pot hydrothermal synthesis of an intermediate followed by its calcination at 1100 °C in air. By exploiting the regulatory effect of the intermediate on Zn and Ga, the depth of traps in 170 nm-sized ZGC nanoparticles was enhanced to above 0.8 eV, and the PersL duration to more than 24 h, with an average lifetime of up to 216 s. An in vivo experiment shows that tumors can be accurately delineated for more than 3 hours. This strategy largely resolves the conflict between the particle size and PersL properties of PLNPs, and expands the application of PLNPs in bio-imaging.

One-Pot Synthesis of Nanostructured Ni@Ni(OH)2 and Co-Doped Ni@Ni(OH)2 via Chemical Reduction Method for Supercapacitor Applications.

Crystalline Ni@Ni(OH)2 (cNNH) and Co-doped cNNH were obtained via a simple one-pot hydrothermal synthesis using a modified chemical reduction method. The effect of each reagent on the synthesis of the nanostructures was investigated concerning the presence or absence of each reagent. The detailed morphology shows that both nanostructures consist of a Ni core and Ni(OH)2 shell layer (~5 nm). Co-doping influences the morphology and suppresses the particle agglomeration of cNNH. Co-doped cNNH showed a specific capacitance of 1238 F g-1 at 1 A g-1 and a capacitance retention of 76%, which are significantly higher than those of cNNH. The enhanced performance of the co-doped cNNH is attributed to the reduced path length of the electrons caused by the decrease in the size of the nanostructure and the increased conductivity due to Co ions substituting Ni ions. The reported synthesis method and electrochemical behaviors of cNNH and Co-doped cNNH affirm their potential as electrochemically active materials for supercapacitor applications.

Facile One-Pot Hydrothermal Synthesis of Hierarchical MoS2/α-MnS Nanocomposites with Good Cycling Performance as Anode Materials for Lithium-Ion Batteries

The design of nanoscale composites with a hierarchical structure can improve the poor cycling performances of transition metal sulfides such as anode materials. The hierarchical MoS2/α-MnS nanocomposites were synthesized by a facile one-pot hydrothermal method in this study, aiming to improve the cycling performance. As an anode material, hierarchical MoS2/α-MnS nanocomposites deliver a high reversible capacity, of 1498 mAh g−1 at a current density of 50 mA g−1; a capacity of ~800 mAh g−1 is maintained over 100 cycles at 300 mA g−1, and a capacity of 907 mAh g−1 is obtained at 1200 mA g−1. Moreover, these capacities increase with the number of cycles, which is mainly owed to the occurring metallic nanoparticles that catalyze the developing polymeric film and enhance the conductivity of the active materials during the electrochemical reactions. The good cycling performances are attributed to the synergistic effects between MoS2 and α-MnS.

CTAB-assisted one-pot hydrothermal synthesis of Co0.85Se as a promising cathode material for magnesium ion battery

• Co 0.85 Se-CTAB was successfully prepared through one-pot hydrothermal method. • Co 0.85 Se-CTAB as magnesium-ion battery cathode material showed a high capacity and fast activation rate. • Two-step magnesium storage mechanism of Co 0.85 Se-CTAB as cathode in MIBs was revealed. Co 0.85 Se with Cetyl-trimethylammonium bromide (CTAB) prepared by the one-pot hydrothermal method is used as a cathode material for magnesium ion battery (MIB) for the first time. It exhibits higher initial capacity (348 mAh g -1 ) and reversible capacity (127 mAh g -1 ) than that of the untreated Co 0.85 Se. The obvious improvement can be ascribed to the enhanced conductivity and the lowered charge-transfer resistance (R ct ) when CTAB is introduced. Moreover, the two-step magnesium storage mechanism of Co 0.85 Se-CTAB in MIB is investigated. This work provides a novel method to enhance the electrochemical properties of metal selenides as electrodes for magnesium ion batteries by adding CTAB cationic surfactants.

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.

Nitrogen, sulfur, and phosphorus Co-doped carbon dots-based ratiometric chemosensor for highly selective sequential detection of Al3+ and Fe3+ ions in logic gate, cell imaging, and real sample analysis

Heteroatom-doped photoluminescent (PL) carbon dots (CDs) have recently gained attention as optical sensors due to their excellent tunable properties. In this work, we propose a one-pot hydrothermal synthesis of PL nitrogen (N), sulfur (S), and phosphorus (P) co-doped carbon dots (NSP-CDs) using glutathione and phosphoric acid (H3PO4) as precursors. The synthesized NSP-CDs were characterized using different spectroscopic and microscopic techniques, including ultraviolet–visible (UV–Vis) spectroscopy, fluorescence spectroscopy, Fourier-transform infrared (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analysis. The NSP-CDs exhibited excellent PL properties with green emission at 492 nm upon excitation at 417 nm, a high quantum yield of 26.7%, and dependent emission behavior. The as-prepared NSP-CDs were spherical with a well-monodispersed average particle size of 5.2 nm. Moreover, NSP-CDs demonstrate high PL stability toward a wider pH, high salt ionic strength, and various solvents. Furthermore, the NSP-CDs showed a three-state “off–on–off” PL response upon the sequential addition of Al3+ and Fe3+ ions, with a low limit of detection (LOD) of 10.8 nM for Al3+ and 50.7 nM for Fe3+. The NSP-CD sensor can construct an INHIBIT logic gate with Al3+ and Fe3+ ions as the chemical inputs and emissions as the output mode. Owing to an excellent tunable PL property and biocompatibility, the NSP-CDs were applied for sensing Al3+ and Fe3+ ions as well as live cell imaging. Furthermore, NSP-CDs were designed as PL sensors for detecting Al3+ and Fe3+ ions in real water show their potential application.

Boosting zinc storage in potassium-birnessite via organic-inorganic electrolyte strategy with slight N-methyl-2-pyrrolidone additive

The environmental-friendly and inexpensive birnessite is deemed as a potential cathode material for aqueous Zn-ion batteries (AZIBs). However, its electrochemical property is mainly enslaved to the unstable interlayer structure and side reaction aggravated by aqueous solvation. Herein, a potassium-birnessite (K0.14MnO1.96) cathode is prepared with a convenient one-pot hydrothermal synthesis, and a genuine insight into strengthening Zn2+energy storage efficiency via desolvation strategy with a low concentration of N-methyl-2-pyrrolidone (NMP) additive is proposed, which is also supported by the density functional theory (DFT) calculation. According to the result, the N-6 sample with enhanced kinetics and pseudocapacitance characteristics exhibits an optimum performance including terrific coulombic efficiency (CE) of ∼ 99.9%, impressive specific energy of 425.66 Wh kg−1, and long cyclic stability of 95.96% at 1 A g−1 after 2000 charge-discharge cycles, and specifically the cathodic by-product Zn4SO4(OH)6·4H2O as a major factor leading to properties deterioration for AZIBs is barely visible in the N-6 sample. Hence, this work opens up a simple but novel perspective of solvation barrier remission via organic-inorganic electrolyte strategy to promote aqueous zinc storage in birnessite.

Nitrogen-doped reduced graphene oxide/MoS2 ‘nanoflower’ composites for high-performance supercapacitors

Mixed-phase (MP) metal disulfides have interesting electrochemical properties which originate from the generation of the abundance of electrochemically active sites and a higher structural stability as compared with crystalline materials. However, there is less exploration in the design and performance of the MP materials for supercapacitors application. Herein, nitrogen-doped reduced graphene oxide (N-rGO) with MP molybdenum disulfide (MoS2) nanoflower (NGM) nanocomposite was self-assembled in a one-pot hydrothermal synthesis. The NGM nanocomposites featured a high surface area and electrical conductivity governed by the uniform growth of nanoflowers on the conductive N-rGO sheets. Coupled with an interconnected network of charge transport channels, the robust ion transport and lowered charge transfer resistance at the electrode-electrolyte interphase significantly boost the electrochemical activity enabling the electrodes to deliver a high specific capacitance (539.5 F g−1), exceptional energy and power densities (Pmax = 25.4 kW kg−1, and Emax = 71.5 Wh kg−1) and excellent capacitance retention of 95.3 % during long-term cycling.

Synthesis of active-site rich molybdenum-doped manganese tungstate nanocubes for effective electrochemical sensing of the antiviral drug (COVID-19) nitazoxanide

Nitazoxanide (NTZ), a promising antiviral agent, is currently being tested in clinical trials as a potential treatment for novel coronavirus disease 2019 (COVID -19). This paper describes a one-pot hydrothermal synthesis to prepare molybdenum (Mo)-doped manganese tungstate nanocubes (Mo–MnWO4 NCs) for the electrochemical sensing of NTZ. The as-prepared Mo–MnWO4 NCs were characterized using various techniques such as XRD, Raman, FE-SEM, FE-TEM, and XPS to confirm the crystal structure, morphology, and elemental composition. The obtained results demonstrate that Mo doping on MnWO4 generates many vacancy sites, exhibiting remarkable electrochemical activity. The kinetic parameters of the electrode modified with Mo–MnWO4 NCs were calculated to be (Ks) 1.1 × 10−2 cm2 s−1 and (α) 0.97, respectively. Moreover, a novel electrochemical sensor using Mo–MnWO4 NCs was fabricated to detect NTZ, which is used as a primary antibiotic to control COVID-19. Under optimal conditions, the electrochemical reduction of NTZ was determined with a low detection limit of 3.7 nM for a linear range of 0.014–170.2 μM with a high sensitivity of 0.78 μA μM−1 cm−2 and negligible interference with other nitro group-containing drugs, cations, and anions. The electrochemical sensor was successfully used to detect NTZ in the blood serum and urine samples and achieved high recoveries in the range of 94–99.2% and 95.3–99.6%, respectively. This work opens a way to develop high-performance sensing materials by exploring the introduction of defect engineering on metal tungstates to detect drug molecules for practical applications.