One-pot Hydrothermal Method Research Articles

Facile synthesis and first principles calculations of Li-MoS2/rGO nanocomposite for high-performance supercapacitor applications

Two-dimensional (2D) nanostructured materials such as graphene oxide nanosheets and molybdenum disulfide (MoS2) are potential candidates for electrochemical energy storage applications. The layered structure of MoS2 makes it a promising active electrode material for supercapacitors. Lithium (Li) interacted with MoS2/reduced graphene oxide (Li-MoS2/rGO) nanocomposite has been synthesized in two steps using a sonochemical dispersion method, and a one-pot hydrothermal method resulting in few-layered MoS2/rGO nanosheets of 2D heterointerfaces. The Li-MoS2/rGO nanocomposite exhibits a high specific capacitance of 173.3 F g−1 at a current density of 1 A g−1. Furthermore, an asymmetric supercapacitor device fabricated with Li-MoS2/rGO achieves a good energy density of 10.6 Wh kg−1 at a power density of 686.3 W kg−1 and outstanding cycling stability with 81.2 % capacity retention over 10,000 cycles. The dispersion of 2D-MoS2 in water is due to the strong electrostatic interface. The structural and electronic properties are theoretically calculated for pristine and Li-interacted MoS2/rGO heterostructure using density functional theory. A comparison of the density of states plots of the two heterostructures and the difference charge density plot of Li-MoS2/rGO heterostructure clearly brings out the importance of the presence of Li. A value of 64 μF cm−2 for the quantum capacitance for pristine MoS2/graphene heterostructure increases to a value 99 μF cm−2 corroborating the experimental observations and we assign this change to the transfer of charge from the Li atom to the outer S atoms in the MoS2/graphene heterostructure. This comprehensive approach, combining experimental synthesis with computational modelling, significantly advances the development and optimization of high-performance supercapacitor materials in the energy storage field. The Li-MoS2/rGO nanocomposite has excellent electrochemical specific capacitance and long-term cyclic stability and has been effectively used for supercapacitor applications with high electrochemical performance.

Ultrabright silicon nanoparticles combined with o-phenylenediamine for ratiometric fluorescence and smartphone imaging dual-mode detection of nitrite

Nitrite (NO2−) is widely present in the natural environment and human daily life. Excessive NO2− can cause harm to the environment and human health. Herein, silicon nanoparticles (SiNPs) with a fluorescence quantum yield of up to 70 % were synthesised using a one-pot hydrothermal method and combined with the common and inexpensive o-phenylenediamine (OPD) to achieve the detection of NO2−. Upon the addition of NO2−, the blue fluorescence of the SiNPs was quenched due to static quenching and Förster resonance energy transfer (FRET), while the yellow fluorescence of benzotriazole, the reaction product of OPD and NO2−, was enhanced, resulting in the fluorescence color change from blue to yellow. Based on these phenomena, a ratiometric fluorescence sensor integrated with smartphone imaging technology was developed. This sensor is notable for its portability, cost-effectiveness, and satisfactory detection limits (0.016 μM for ratiometric fluorescence and 1.64 μM for smartphone imaging). Importantly, it demonstrates high reliability and practicability in detecting NO2− in real water and food samples. This broadens the application of SiNPs in the sensing field and introduces new possibilities for NO2− detection in complex sample matrices.

Fluorescent Determination of Uric Acid Based on Porphyrin and ZnCo2O4 Nanocomposite.

Advances in porphyrin chemistry have provided exciting technologies in the field of optical biosensing. Herein, we have synthesized 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and porous Zn0.1Co2O4 nanorods using a simple one-pot hydrothermal method. The obtained TCPP- Zn0.1Co2O4 composite was then used for the development of a novel optical sensor for the determination of uric acid (UA), which is an important biomarker in human urine, serum or saliva for the clinical diagnosis of hyperuricemia and hypouricemia, etc. TCPP-Zn0.1Co2O4 composite was characterized using SEM, TEM, EDAX, PXRD, FT-IR, UV-Visible, and NMR spectroscopic techniques. The fluorescence emission spectral analysis of TCPP-Zn0.1Co2O4 was then investigated for potential applications in the detection of uric acid via the fluorescence quenching mechanism. The designed sensor showed a linear response towards the uric acid in the concentration range of 0.99 to 5.2 nM. The optical sensor exhibits a sensitive response to uric acid with a detection limit of 0.015 nM. The sensor was employed to quantify UA in spiked human urine samples and artificial urine with satisfactory results.

Iron Single-Atom Nanozyme with Inflammation-Suppressing for Inhibiting Multidrug-Resistant Bacterial Infection and Facilitating Wound Healing.

Infection with drug-resistant bacteria and the formation of biofilms are the main factors contributing to wound healing insufficiency. Antibacterial agents with enzyme-like properties have exhibited considerable potential for efficient eradication of drug-resistant microorganisms due to their superior sensitivities and minimal side effects. In this work, we prepared a kind of Fe-centered single-atom nanozyme (Fe-SAzyme) with high biocompatibility and stability via a facile one-pot hydrothermal method, which was suitable for the treatment of wounds infected with drug-resistant bacteria. The Fe-SAzyme exhibited remarkable peroxidase-like catalytic activities, catalyzing the conversion of hydrogen peroxide (H2O2) to highly toxic hydroxyl radicals (•OH), which could not only damage bacterial cells but also inhibit, disrupt, and eradicate the formation of bacterial biofilms. Thus, Fe-SAzyme demonstrated a broad-spectrum antibacterial performance capable of effectively eliminating multidrug-resistant bacteria. The coexistence of ferrous (Fe2+) and ferric (Fe3+) ions in Fe-SAzyme conferred the nanozyme with anti-inflammatory activity, effectively suppressing excessive inflammation. Meanwhile, Fe-SAzyme could significantly downregulate inflammatory cytokines tumor necrosis factor-α and interleukin-1β and upregulate growth factors VEGF and epidermal growth factor, which can prevent bacterial infection, mitigate inflammation, promote fibroblast proliferation, and improve wound closure. Thus, Fe-SAzyme had shown favorable therapeutic efficiency in promoting bacteria-infected wound healing. This study provides Fe-SAzyme as a promising candidate for the development of new strategies to treat multidrug-resistant bacterial infections.

Self-Assembled 8-Ti-Containing Polyoxomolybdate for the Photocatalytic Hydrogen Evolution.

An S-shaped 8-Ti-containing polyoxomolybdate (NH4)Cs2Na6H3[Ti8(GeMo9O34)2(GeMo5O23)2]·44H2O (1) has been prepared under the one-pot hydrothermal method and further characterized. According to single-crystal X-ray, compound 1 consists of two {GeMo9O34} and two {GeMo5O23} segments, which are linked with a {Ti8O34} cluster. Moreover, the {GeMo5O23} fragment is rare and the first discovery, which enriches the lacunary Keggin-type family and offers the possibility of obtaining new structures. Among all of the reported polyoxomolybdates, compound 1 has the highest nuclearity of Ti centers. From the photocatalytic hydrogen evolution studies, compound 1 can be used as the heterogeneous catalyst with an H2 evolution rate of 2392.6 μmol g-1 h-1 under minimally optimized conditions.

MoS2 nanosheet assisted poly vinyl alcohol cross-linked with carboxylated acryl-amido-2-methyl-1-propanesulfonic acid in medium temperature proton exchange membrane fuel cell application

ABSTRACT Initially, the carboxylated-acryl amido propane sulfonic acid (C-AMPSA) was synthesized through the thiol-ene reaction using 2-acrylamido-2-methylpropane sulfonic acid and 3-mercapto propane sulfonic acid monomers. The C-AMPSA was cross-linked with polyvinyl alcohol to create a non-perfluorinated membranes were of these acid group-containing monomers. Using a cross-linking technique, a poly vinyl alcohol cross-linked C-AMPSA (PVA-C-AMPSA) polymer was prepared. Following that, the MoS2 nanosheets (NSs) were synthesized through the one-pot hydrothermal method, and their phase purity, functionality, and morphology were evaluated by p-XRD, FT-IR, and FE-SEM analyses. These nanosheets were then incorporated into PVA-C-AMPSA polymer nanocomposite membranes at various concentrations (0%, 1%, 2%, 3%, and 5% by weight). In addition, the physicochemical properties of bare and MoS2 nanosheets incorporated PVA-C-AMPSA polymer nanocomposite membranes were assessed, including water uptake, swelling ratio, and ion-exchange capacity. Remarkably, the membrane with 5% of MoS2 NSs in PVA-C-AMPSA displayed an ion-exchange capacity of 1.13 mmol g−1 and a proton conduction of 1.8 × 10−3 S cm−1 at 110°C. The Arrhenius plot indicated that the proton transport was involved in both Grotthuss and vehicular mechanisms. In the fuel cell testing, the PVA-C-AMPSA polymer nanocomposite membrane containing MoS2 NSs demonstrated superior performance, achieving a peak power density (PD) exceeding 0.7 W cm−2 and an open-circuit voltage (OCV) surpassing 0.93 V at 110°C. In contrast, the pure PVA-C-AMPSA membrane exhibited a peak PD of over 0.4 W cm−2 and an OCV of around 0.6 V at the same temperature. Additionally, the 5% of MoS2 NSs incorporated PVA-C-AMPSA polymer nanocomposite membrane exhibited outstanding oxidative stability with 87.7% of degradation when exhibited to a Fenton reagent at 80°C for 8 h.

Controllable Synthesis and Ultrahigh Proton Conduction of a Hydrogen-Bond Network.

The functionalization of polyoxometalates with organic ligands provides a new-style strategy to accurately incorporate polyoxometalates with advanced functional organic moieties on their surfaces, the development of which has attracted increasing research interest due to the potential applications. A germanium tungstate Na2(H3O)6[{RuIV(bpy)}2{WO2(C2O4)}2(GeW11O39)2]·27H2O (bpy = 2,2'-bipyridine) with two ligands covalently modified was triumphantly synthesized, using the conventional one-pot hydrothermal method. It was systematically characterized by thermogravimetric analysis (TGA), elemental analysis, infrared (IR) spectroscopy, single-crystal X-ray diffraction, X-ray photoelectron spectroscopy (XPS), powder diffraction (PXRD), scanning electronic microscopy (SEM), and ultraviolet-visible (UV-vis) spectroscopy. The two-dimensional (2D) layered structure was established through hydrogen bonding and Na+ bridges. Impedance measurements indicate that it displays outstanding proton conduction properties, with a splendid conductivity up to 1.24 × 10-2 S·cm-1 under 353 K and 90% relative humidity (RH), owing to the rich interlayer hydrogen-bond network formed by the organic ligands ({RuC10H8N2}4+ and {WC2O4}4+), hydrated protons (H3O+), and crystal waters.

Suspended Stir Bar Sorptive Extraction Based on Zr-MOF-Modified Cotton Thread for Enrichment and Detection of Three Trace Quinolones in Fish Tissue.

In this study, an efficient and practical method was established to enrich and detect three trace quinolones in fish tissue. Low-cost and environment-friendly cotton threads were coated with PCN-224 using a simple one-pot hydrothermal method. The PCN-224-modified cotton threads (PCN-224@CTs) were characterized to ensure that the crystal was successfully fabricated on the surface of cotton threads. The prepared PCN-224@CTs were wrapped around steel needles to form suspended bars. Key factors of extraction and desorption were optimized, and analytical performance was tested. Suspended bar sorptive extraction coupled with ultra-performance liquid chromatography (UPLC) with a photodiode array detector was used to analyze the quinolones in fish tissue. The detection limits of quinolones were 0.26-1.15ng/mL, and the recoveries were achieved in the range of 81.31%-115.81%, indicating a simple method with high sensitivity and satisfactory practicability of enriching, separating, and detecting trace quinolones was successfully established.

Single-Atom Cobalt Catalyst with Boron and Nitrogen Codoped Graphene (Co-BN-G) Enables Adsorption and Catalytic Conversion of Polysulfides for High-Performance Lithium-Sulfur Batteries.

In lithium-sulfur batteries, the shuttling effect and sluggish redox conversion of soluble polysulfides lead to unsatisfactory sulfur utilization and capacity retention. In this research, we used a one-pot hydrothermal method to prepare graphene with single-atom Co and B, N codoped as a sulfur host in Li-S batteries, thereby suppressing the shuttling effect and facilitating the redox conversion of lithium polysulfides (LiPSs). A series of characterizations demonstrated that dual doping of B and N introduces more lattice defects and structural deformations in graphene oxide, thus enhancing its adsorption of polysulfides. Simultaneously, single-atom cobalt can also polarize adsorption and accelerate the conversion reaction of LiPSs. The Li-S cell with the as-prepared Co-BN-G sulfur host materials exhibited an excellent capacity of 1034 mAh g-1 at 0.5 C and satisfactory cycle performance (retention of 69% over 500 cycles). Even at a rate of 2 C, a discharge capacity of 851 mAh g-1 is achieved. The results show that the Co-BN-G configuration efficiently captures LiPSs and enhances their rate conversion kinetics in redox reactions, demonstrating significant practical potential.

Photocatalytic degradation of norfloxacin antibiotic by a novel Cu-ZnO/BiOI/Bi2WO6 double Z-type heterojunction: Performance, mechanism insight and toxicity assessment

A novel double Z-type Cu-ZnO/BiOI/Bi2WO6 photocatalyst was synthesized using one-pot hydrothermal method. The effects of Bi2WO6 and Cu-ZnO contents, antibiotic concentration, catalyst dosage, solution pH value, coexisting ions, antibiotic types, mixed antibiotic types, water source and light source on the catalytic performance of the Cu-ZnO/BiOI/Bi2WO6 were investigated. Remarkably, under visible light irradiation, the removal rate of 20 mg/L norfloxacin reached 94.32 % within 120 min using the optimized Cu-ZnO/BiOI/Bi2WO6 photocatalyst, and its pseudo-first-order reaction rate constants were 5.63 and 1.80 times higher than those of BiOI and BiOI/Bi2WO6, respectively. The toxicity prediction and experimental findings indicated that the toxicity of the degraded norfloxacin (NOR) solution was notably diminished. The Cu-ZnO/BiOI/Bi2WO6 catalyst exhibited excellent salt tolerance, high reusability stability, universality and spectral response. Outstanding photocatalytic performance of Cu-ZnO/BiOI/Bi2WO6 photocatalyst is primarily due to the co-recombination of Cu-ZnO and Bi2WO6 on BiOI, which increases the surface area and active sites of the catalyst. More importantly, the double Z-type heterojunction, created through the intimate union of the semiconductor boundary within the composite catalyst, enhances the interface charge transport efficacy and the efficiency of separating photogenerated carriers. Finally, in conjunction with a diverse range of experimental methodologies, the degradation pathway of NOR through the Cu-ZnO/BiOI/Bi2WO6 composite catalyst and the electron transfer mechanism within the double Z-type heterojunction have been comprehensively elucidated. This study provides a pioneering reference for optimizing BiOI-based heterojunction catalysts and addressing antibiotic-contaminated wastewater treatment.

CO2(OH)2CO3 and Fe doped Co2(OH)2CO3 prepared as efficient and stable catalysts for activation of PMS: Two systems comparison and key role of high-valent metal-oxo species in mechanism revealing

High-valent metal-oxo species [M(IV) = O] exhibited high selectivity and chemical efficiency in advanced oxidation processes for removing organic pollutants, making their manipulation essential in catalytic systems. However, the low and unsustainable efficiency of generating M(IV) = O posed significant challenges. In this research, Co2(OH)2CO3 were successfully prepared via a one-pot hydrothermal method to efficiently activate peroxymonosulfate (PMS) with high-valent cobalt-oxo species [Co (IV) = O] as the primary active oxidation species. Building upon this foundation, COC was modified through variations in metal types and elemental ratios, in which magnetically enriched FexCo2-x(OH)2CO3 was synthesized by gradient Fe doping with higher catalytic efficiency and stability. The insertion of Fe resulted in the lengthening of the Co-O bond and improved the valence distribution of cobalt on the COC surface. Besides, it enabled part of the electrons to be transferred from the Fe active center to the Co active center, breaking the limitation of the traditional two-electron transfer and realizing the stable generation of more high-valent metals. Both reaction systems achieved efficient degradation of sulfadimethoxine (SDM) within 30 min and were able to completely degrade SDM within 30 min even after three cycles. FexCo2-x(OH)2CO3 maintained excellent catalytic performance even after 30 days of exposure to air. In both systems, high-valence metals played a dominant role, while the contributions of hydroxyl radicals and sulfate radicals were negligible. Overall, the two groups of developed catalysts both showed remarkable stability and pollutant removal performance in anions, humic acid, Different antibiotics and real water systems, which provided a new perspective on antibiotic removal.

Photothermal synergistic catalytic oxidation mechanism of toluene by Ce-doped SrTiO3 via one-pot hydrothermal synthesis

Industrial volatile organic compounds (VOCs) emissions pose significant environmental and human health risks, with photothermal catalysis degradation emerging as a promising VOCs treatment technology. The light response range and catalysis degradation efficiency of photocatalysts, however, need to be improved. This study prepared Ce-doped SrTiO3 perovskite catalysts via a one-pot hydrothermal method. The synergistic photic/thermal degradation mechanism of toluene was uncovered via XPS, Uv–Vis, EPR, and in-situ DRIFTS analysis. It was found that the toluene removal rate and CO2 yield reached their maximums at 200 °C, reaching 95 % and 90 %, respectively, at a Ce doping ratio of 50 %. During the catalytic process, the prerequisite to trigger toluene oxidation, and light promote the generation of reactive oxygen species (·OH and ·O2–), which facilitates the formation of intermediates and thus accelerates the deep oxidation of toluene. The doped Ce increases surface oxygen vacancies while lowering the energy band gap of the catalyst, facilitating the separation of holes and photogenerated electrons. Furthermore, in situ DRIFTS studies demonstrated that toluene undergoes a ring-opening process, producing intermediates such as benzaldehyde and benzoic acid. This study will assist in promoting the use of photothermal synergistic catalytic degradation technology to remove VOCs from industrial sources.

Oxidative desulfurization of dibenzothiophene over V-Mo co-doped akaganeite

In this paper, V-Mo co-doped akaganeite (β-FeOOH) was prepared by one-pot hydrothermal method and the oxidative desulfurization (ODS) of dibenzothiophene over the catalyst was carefully investigated. 0.07g (ca. 0.35wt.% of model oil) of catalyst induced 100% of DBT removal in 60min with a O/S of 20:1 under 60 °C for the model oils with any of the sulfur contents, 100 ppm, 500ppm, or 1000 ppm. Moreover, the DBT removal after recycling 4 times is still 100% and it only declines to 98.04% in the fifth cycle, which indicates that the catalyst has a good stability and recycling performance. Doping V species in Mo doped β-FeOOH not only initiates a micro-variation in catalyst structure and the resultant more active •OH species but also forms a more stable structure of the catalyst, enabling the catalyst to exhibit a higher ODS reaction rate and a better reusability. The GC-MS analyses demonstrated that the DBT was converted to DBTO2 by two steps: (1) DBT→ DBTO; (2) DBTO→ DBTO2, and the former is the rate-limiting step.

Metal-free carbon-dots nanozyme with oxidase-like activity as photocatalysts for highly efficient detection/reduction of Cr(VI) and antibacterial application

Wastewater containing Cr(VI) and bacteria indicated significant challenges and threats to public health and ecological environments. Hence, it is necessary to construct novel method for detecting and treatment such wastewater. Non-metal-doped carbon dots nanozyme (TA-CDs) were effectively synthesized by one-pot hydrothermal method utilizing tartaric acid (TA) and L-tryptophan (L-trp) as ingredients. TA-CDs revealed excellent water solubility, optical stability, and biocompatibility. Particularly noteworthy, TA-CDs (150 μg/mL) exhibited outstanding light-responsive oxidase-like activity, efficiently generating e-, O2∙- and CO2∙-. Furthermore, TA-CDs illustrated an exceptional linear relationship with Cr(VI) in an extensive detection range and low detection limits (0.51 μM), as well as high selectivity and anti-interference properties. Simultaneously, TA-CDs also demonstrated significant photocatalytic activity, achieving approximately 70.26 % reduction in 40 mg/L Cr(VI) and realized excellent antimicrobial performance (inhibition rates of 97.18 % and 82.67 % against E. coli and S. aureus, respectively). In short, this research not only provided a multifunctional carbon-dots nanoenzyme for recognition, photoreduction of Cr(VI), and photodynamic antibacterial application, but also offered novel strategy and methodology for detection and treatment of water containing heavy metals and microorganisms.

Catalytic ethanolysis of Xiaojihan subbituminous coal to platform chemicals enhanced by pre-oxidation with ozone

Xiaojihan subbituminous coal (XSBC) was pre-oxidized by ozone to prepare oxidized XSBC (OXSBC). Then, the ethanolysis was conducted on OXSBC at 300 °C under an initial nitrogen pressure (INP) of 1 MPa for 2 h. On this basis, the influences of pre-oxidation conditions on the content of oxygen-containing functional groups and the yield of soluble portion (SP) from the ethanolysis of XSBC and OXSBC were explored. The research results show that the yield of SP from the OXSBC ethanolysis is higher than that from the XSBC ethanolysis, and the highest yield of SP from the OXSBC ethanolysis reaches 24.9 wt% at 50 °C for 3 h, an increase of 80.4 % compared to the yield of SP from the XSBC ethanolysis. Besides, the magnetic nanosphere Co-CuFe2O4 catalyst, prepared by adopting the one-pot hydrothermal method, was applied to the catalytic ethanolysis (CE) of OXSBC3 at 300 °C, 1 MPa INP, and 2 h. The catalyst is noticeably active in the CE of OXSBC3, as it promotes the yields of SP and oxygen-containing organic compounds obtained from the OXSBC3 ethanolysis from 24.9 wt% and 76.25 mg g−1 to 42.8 wt% and 204.16 mg g−1, respectively. The CE of the model compound demonstrates that ethanol is activated by Co-CuFe2O4 to release H+, H-, and +CH2CH3, which play a crucial role in the conversion of benzyloxybenzene. This study provides a novel approach for acquiring value-added organic chemicals from low-rank coals.

Construction of an in-situ Se-linked ZnSe/ZnO heterojunction for efficient photocatalytic U(VI) reduction

U(VI) in nuclear wastewater threatens human health and the environment due to its high toxicity and mobility. Photocatalysis is seen as a promising, simple, low-cost, and sustainable method for wastewater treatment, but existing photocatalysts face challenges like complex preparation and severe electron-hole recombination. In this work, ellipsoidal Se-linked ZnSe/ZnO was in situ constructed using a simple one-pot hydrothermal method, with non-metallic selenium serving as the carrier. In 30 minutes, the removal rate of U(VI) can reach 90.2 % in 100 mg/L U(VI) solution. The reaction kinetics of the optimal Se/ZnSe/ZnO ratio reached 0.14939 min−1, which is nearly 10 times that of pure ZnO. Photocatalytic analysis revealed that introducing Se as the medium for electron transport in the composite material can effectively reduce electron-hole recombination, thereby enhancing photocatalytic efficiency. The results of this study offer a simple and efficient new method for photocatalytic reduction of U(VI) and provide an effective strategy for establishing a conductive medium in the heterojunction using a one-pot hydrothermal method.

The one-pot synthesis of defect-rich bimetallic MOFs for efficient photocatalytic Fenton degradation of organic pollutants

The efficient and straightforward treatment of organic contaminants in water remains a significant challenge. This study presents the synthesis of a defective NH2-MIL-88Fex/Cuy photo-Fenton catalyst via a simple one-pot hydrothermal method. The incorporation of the inexpensive metal Cu enhances the valence cycles of Cu2+/Cu+ and Fe3+/Fe2+ under the photo-Fenton system, thereby compensating for the rapid consumption rate of ·OH radicals. Degradation tests demonstrated that NH2-MIL-88Fe0.5/Cu0.5 can degrade 99.99 % of methylene blue within 30 min under visible light irradiation. Free radical trapping experiments and Electron Paramagnetic Resonance (EPR) confirmed that ·OH radicals play a predominant role in the catalytic system. Density Functional Theory (DFT) calculations verified the improved binding energy of the catalyst materials following the introduction of structural defects. The degradation pathway and mechanism of methylene blue were elucidated. This study offers a novel approach for designing photo-Fenton catalysts and holds significant promise for practical applications in wastewater treatment.

Eco-Friendly synergistic energy generation: Co-Ni2S4 nanoparticles with S-g-C3N4 as a dual-action electrocatalyst for sustainable water splitting

The most appealing technique for producing hydrogen fuel is electrochemical water splitting, which uses natural water cycle capabilities from renewable sources. The transition metal sulfide family includes nickel sulfide (NiS), which is promising for electrochemical water splitting as an exceptionally efficient, stable, and active electrocatalyst. Nickel sulfide (NiS), a series of cobalt-doped nickel sulfide (CoNi2S4) by varying weight percentages of Co (2, 4, 6, 8, wt %) and a series of sulfur-doped graphitic carbon nitride (SGCN) composite with 6 % CoNi2S4 by varying weight percentage of SGCN (10, 30, 50, 70, 90, wt %) were all synthesized using one-pot hydrothermal method. Structural morphologies and composition of the synthesized nanoparticles (NPs) and nanocomposites (NCs) were investigated using SEM, EDX, FTIR, and XRD characterization techniques. The electrochemical performance was examined via voltammetric, electrochemical impedance, and chronoamperometric studies. Outcomes suggest that composite 70 % SGCN@6 % CNS is the best electrocatalyst with the smaller Tafel slope (107 mVdec-1), lowest overpotentials (440 mV@10 mAcm−2), and minor charge transfer resistance (15 Ω) as electrode materials for electrochemical water splitting. The present research provides a workable approach for creating efficient bifunctional electrocatalysts for total water splitting, it can be inferred from the data.

One-pot amination and carboxylation functionalization of lignin for efficient adsorption of Cr(VI) and Cd(II): Influence of functional groups on adsorption equilibrium and mechanism

The removal of multiple heavy metal pollutants remains a challenge. Amination and carboxylation modified lignins (NCLs) prepared by one-pot hydrothermal method were used as adsorbents for Cr(VI) and Cd(II) removal. The oxygenous groups content in adsorbents was quantitatively analyzed by Boehm titration in which NCL10 (the mass ratio of citric acid: triethylene diamine = 10) possessed a maximum carboxyl group content of 1.22 mmol/g. The Langmuir adsorption isotherm model was the most suitable, with the highest theoretical adsorption capacity of Cr(VI) and Cd(II) of 1298.6 and 103.1 mg/g, respectively. Meanwhile, FT-IR and XPS exhibited that NCL5 surface contained many functional groups beneficial to the removal of Cr(VI) and Cd(II). The contribution of carboxyl and hydroxyl groups to the removal of Cr(VI) and Cd(II) was quantitatively analyzed. After the blocking of carboxyl and hydroxyl groups, the adsorption rate of Cr(VI) and Cd(II) decreased by 26.4 %, 67.7 % and 7.2 %, 43.3 %, respectively. This study provides effective strategies to overcome the limitations of lignin adsorbents for wastewaters containing a wide range of heavy metal pollutants.

Green synthesis of carbon dots from Hakka yellow wine lees: Characterization and applications for Fe3+ and NaFeEDTA sensing

In this study, Hakka yellow wine lees carbon dots (HYWL-CDs) with an average diameter of 1.75 nm are synthesized from Hakka yellow wine lees (HYWL) via a one-pot hydrothermal method. Results of X-ray photoelectron spectroscopy and FTIR reveal the presence of C=C and –OH in the HYWL-CDs. Additionally, the HYWL-CDs present excitation-wavelength dependence, with maximum excitation and emission wavelengths of 360 and 440 nm, respectively. The fluorescence of the HYWL-CDs can be quenched by Fe3+. The Fe3+ concentration is correlated linearly with the quenching rate over a linear range of 0.6–1.1 mg/mL, and the limit of detection is 0.18 μg/mL. And phenols have been shown to be present in HYWL-CDs, and the color reaction between phenols and FeCl3 is most likely the mechanism by which FeCl3 causes fluorescence burst in HYWL-CDs. Moreover, the HYWL-CDs demonstrate significant potential for detecting NaFeEDTA in iron-fortified soy sauces, the linear-fit equation was y = 185.38x + 1024.6 (R2 = 0.9995) The HYWL-CDs are loaded onto paper strips, iron-fortified straw mushroom dark soy sauce showed noticeable color changes, which allows one to differentiate normal soy sauce from iron-fortified soy sauce more conveniently and provides a new perspective for the high-value utilization of yellow wine lees.