One-pot Hydrothermal Procedure Research Articles

Improving azo dyes degradation by CoFe2O4-activated peroxymonosulfate: Performance, degradation mechanism, and ecotoxicity assessment

Development of an effective catalyst is essential to eliminate the risks to ecological environment and human health caused by the accumulation of azo dyes in environmental water. Herein, the cobalt ferrite (CoFe2O4) nanoparticles (NPs), facilely prepared by a one-pot hydrothermal procedure, were developed for peroxymonosulfate (PMS) activation towards Congo red (CR) degradations. The key experimental parameters were comprehensively investigated to optimize the degradation performance for CR in CoFe2O4/PMS system. Under optimal conditions, the CoFe2O4 NPs exhibited an excellent capability for PMS activation to degrade CR with the degradation efficiency of nearly 100 % in a wide range of pH values (3.0–9.0). The electron paramagnetic resonance (EPR) and quenching experiments confirmed that the entire CR degradation process was dominantly by the non-radical (1O2) and surface-bound SO4·−and ·OH. CoFe2O4 NPs displayed the remarkable stability and reusability, with degradation efficiency of 85.5 % even after six recycles. The possible degradation pathway in CR degradation process was proposed, and the qualitative analysis and ecotoxicity of the degradation intermediates were investigated. This work provided a facile and green strategy to prepare a prospective catalyst for the efficient removal of azo dyes by PMS activation.

One-pot anchoring BaBi2O6/Bi2O3 nanoparticles on oxygen vacancy rich TiO2: Double Z-scheme nanocomposites with QDs size for elimination of wastewater pollutants

The emergence of nanostructured photocatalysts with high activity offers facile solutions for removing water pollutants. In this study, a novel double Z-scheme TiO2-x/BaBi2O6/Bi2O3 nanocomposite with QDs size of about 5.52 nm was prepared by a facile one-pot hydrothermal procedure, and its activity was studied in the photocatalytic degradation of pharmaceutical and dye pollutants. The optimized nanocomposite showed a significant efficiency in the removal of tetracycline, rhodamine B, fuchsine, methylene blue, and chromium (IV), which was 12.4, 7.38, 11.1, 10.2, and 12.1 times higher than pure TiO2-x, respectively. The presence of oxygen deficiency in the crystal lattice of TiO2-x/BaBi2O6/Bi2O3 nanocomposite played a significant role in the effectual separation of photoexcited charges, increasing reactive active sites, and capturing charge carriers. Besides, providing a short distance for the rapid migration of charges to the surface of the nanocomposite was possible with the quantum size of the catalyst particles. Enforced by the established double Z-scheme heterojunctions, the charge segregation was considerably enhanced along with maintaining their redox capability. Finally, biocompatibility tests showed the harmlessness of the treated solution for agricultural use.

Synthesis of N-doped and P-doped silicon quantum dots and their applications for tetracycline detection in the honey samples and antibacterial properties

The abuse of tetracycline can lead to its residue in animal derived foods, posing many potential hazards to human health. Therefore, rapid and accurate detection of tetracycline is an important means to ensure food safety. Nitrogen doped and phosphorus doped silicon quantum dots (N-SiQDs, P-SiQDs) with remarkable optical stability were fabricated via a one-pot hydrothermal procedure in this study. Upon the excitation at 346 nm, N-SiQDs and P-SiQDs emitted fluorescence at 431 nm and 505 nm, respectively. Two SiQDs had the potential to serve as a probe for detecting low concentrations of tetracycline (TC), employing a mechanism of the static quenching effect. The calibration curves of N-SiQDs and P-SiQDs were linear within the range of 0–0.8 μM and 0–0.4 μM, the limits of detection were low as 5.35 × 10−4 μmol/L and 6.90 × 10−3 μmol/L, respectively. This method could be used successfully to detect TC in honey samples. Moreover, the remarkable antibacterial efficacy of two SiQDs could be attributed to the generation of a large number of intracellular reactive oxygen species. The SEM images showed that the structure of bacterial cell was disrupted and the surface became irregular when treated with both SiQDs. These properties enabled potential usage of SiQDs as excellent antibacterial material for different biomedical applications.

Novel solid catalyst sulfonic acid functionalized carbonaceous material for biodiesel production

A one-pot hydrothermal carbonization-sulfonation procedure was employed to develop robust, carbon-based solid catalyst sulfonic acid functionalized carbonaceous material (SAFACAM) possessing acidic functions up to 5.31 mmol g−1 for the first time at 80 °C. With its atom-efficient, one-pot preparation from a plentiful natural biomass derivative (glucose), the current catalyst benefits the environment and has the potential to lower the overall cost of producing biodiesel by converting cheap raw materials. The diminishing supply of fossil fuels coupled with the polluting effects of their use is driving the quest for more sustainable sources of energy. The pursuit of producing biodiesel from affordable, non-edible oil has become progressively significant due to its dual benefits of sustainability and cost-efficiency. In this context, Jatropha curcas oil (JCO) has gained attention in the energy sector, as it holds promise as a viable feedstock for biodiesel manufacturing and a renewable energy solution for numerous nations. Additionally, the catalyst exhibited exceptional physical stability and reactivity throughout 5 consecutive cycles, establishing its potential as a highly promising catalyst for sustainable biodiesel manufacture.

Hybrid FeWO4-Hyaluronic Acid Nanoparticles as a Targeted Nanotheranostic Agent for Multimodal Imaging-Guided Tumor Photothermal Therapy.

Development of versatile nanoplatform still remains a great challenge due to multistep synthesis and complicated compositions. Therefore, it is significant to develop a facile method to synthesize a nanocomposite to achieve multimodal imaging and even imaging-guided cancer therapeutics. In our study, hyaluronic acid-functionalized iron (II) tungstate nanoparticles (HA-FeWO4 NPs) were successfully synthesized as a versatile nanoplatform by a facile one-pot hydrothermal procedure. The formed multifunctional HA-FeWO4 NPs were investigated via a series of characterization techniques, which demonstrated good biocompatibility, excellent dispersion, low cytotoxicity, active tumor-targeting ability and high photothermal efficiency. Furthermore, tumor was clearly visualized by HA-FeWO4 NPs with multimodal imaging of infrared thermal imaging, magnetic resonance imaging, computed tomography imaging in 4T1 tumor bearing mice. More importantly, HA-FeWO4 could achieve multimodal imaging-guided photothermal therapy of 4T1 tumors. The constructed HA-FeWO4 NPs have great potential as ideal nanotheranostic agents for multimodal imaging and even imaging-guided cancer theranostics in biological systems.

Directional regulation and mechanism analysis of the surface properties of hydrothermal carbon by circulating liquid in the hydrothermal carbonization procedure

The complexity of the chemistry behind the hydrothermal conversion is enormous. Components interact with their own physical and chemical structure, making it harsh to understand the conversion as a whole. Herein, the six-water recirculation and loading nano SiO2 experiment in a one-pot hydrothermal carbonization procedure was designed to elucidate the mechanism of regulating the functional groups and microporous structure of the hydrochar surface. The hydrochar prepared by the second circulating liquid and loading nano-SiO2 (HBC-R2/Si) was equipped most enriched functional groups (carboxyl = 11.48 μmol/g, phenolic hydroxyl = 52.98 μmol/g, lactone groups = 46.52 μmol/g) and suitable pore size (1.90 nm–1.93 nm) as a sorbent riched in hemicellulose. The sorption kinetics (equilibrium reached ≈ 480 min) are approximately evenly fitted by the pseudo-second-order, Weber and Morris, and Elovich models, indicating that membranes and particles diffusion, pore diffusion, and surface sorption coexisted in the sorption of methylene blue (MB) on the hydrochar materials. Simultaneously, all hydrochar materials achieved over 25% MB removal within 90 min (liquid membrane diffusion) and over 40% for HBC-R2 and HBC-R2/Si, suggesting that liquid membrane diffusion is the predominant rate-limiting step. Pearson's correlation analysis and Mantel's analysis announced that the cation exchange capacity (CEC), pore size, and carboxyl groups on the hemicellulose affect the sorption capacity by limiting the pore diffusion procedure. However, the CEC and the phenolic hydroxyl groups on the cellulose and hemicellulose affect the sorption rate by limiting membrane diffusion. Three consecutive sorption/desorption cycles confirmed the high stability and reusability of HBC-R2/Si composites.

One-pot synthesis of magnetic cellulose nanocrystal and its post-functionalization for doxycycline adsorption

The composite of magnetite (Fe3O4) and cellulose nanocrystal (CNC) is considered a potential adsorbent for water treatment and environmental remediation. In the current study, a one-pot hydrothermal procedure was utilized for magnetic cellulose nanocrystal (MCNC) development from microcrystalline cellulose (MCC) in the presence of ferric chloride, ferrous chloride, urea, and hydrochloric acid. The x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy analysis confirmed the presence of CNC and Fe3O4, while transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis verified their respective sizes (< 400 nm and ≤ 20 nm) in the generated composite. To have an efficient adsorption activity for doxycycline hyclate (DOX), the produced MCNC was post-treated using chloroacetic acid (CAA), chlorosulfonic acid (CSA), or iodobenzene (IB). The introduction of carboxylate, sulfonate, and phenyl groups in the post-treatment was confirmed by FTIR and XPS analysis. Such post treatments decreased the crystallinity index and thermal stability of the samples but improved their DOX adsorption capacity. The adsorption analysis at different pHs revealed the increase in the adsorption capacity by reducing the basicity of the medium due to decreasing electrostatic repulsions and inducing strong attractions.

Conversion of lignite-derived volatiles into aromatics over Zn@MCM-41 and ZSM-5 tandem catalysts with a high stability

Direct conversion of lignite into light aromatics via catalytic fast pyrolysis is a great challenge because of severe catalyst deactivation and low aromatics yield. The tandem catalysis (1Zn@MCM-41 and ZSM-5) system was employed to promote the conversion of thermally-derived volatiles of lignite into aromatics at 600 °C. The mesoporous Zn-incorporated MCM-41 (xZn@MCM-41) with different doping amount of Zn was prepared with a one-pot hydrothermal procedure. The structure and the dispersion of Zn species of 1Zn@MCM-41 were systematically studied with XRD, SEM, BET, NH3-TPD and so on. The presence of 1Zn@MCM-41 significantly expands the lifetime of the microporous ZSM-5. Meanwhile, the yield of aromatics, especially benzene, is also increased to some extent. The content of the long-chain hydrocarbons and the phenolic compounds are decreased significantly after being cracked by the mesoporous 1Zn@MCM-41. More small molecules are able to contact with the active sites located in the micropores of ZSM-5 with the presence of Zn@MCM-41. In addition, the ZSM-5 in the tandem catalysts system presents an excellent stability. Therefore, this meso-microporous tandem catalysis system promotes the preferential cracking of macromolecular compounds, the cracked small molecules generated from which then contact with ZSM-5 to produce aromatics. This work provides a new perspective for the gradient catalyzing lignite-derived volatiles over a tandem catalysis system.

UV-Based Advanced Oxidation Processes of Remazol Brilliant Blue R Dye Catalyzed by Carbon Dots.

UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82−) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82−, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min−1 and UV/1.02 mM S2O82−/TIP-CD-0.0345 min−1.

Moss-like Hierarchical Architecture Self-Assembled by Ultrathin Na2Ti3O7 Nanotubes: Synthesis, Electrical Conductivity, and Electrochemical Performance in Sodium-Ion Batteries.

Nanocrystalline layer-structured monoclinic Na2Ti3O7 is currently under consideration for usage in solid state electrolyte applications or electrochemical devices, including sodium-ion batteries, fuel cells, and sensors. Herein, a facile one-pot hydrothermal synthetic procedure is developed to prepare self-assembled moss-like hierarchical porous structure constructed by ultrathin Na2Ti3O7 nanotubes with an outer diameter of 6–9 nm, a wall thickness of 2–3 nm, and a length of several hundred nanometers. The phase and chemical transformations, optoelectronic, conductive, and electrochemical properties of as-prepared hierarchically-organized Na2Ti3O7 nanotubes have been studied. It is established that the obtained substance possesses an electrical conductivity of 3.34 × 10−4 S/cm at room temperature allowing faster motion of charge carriers. Besides, the unique hierarchical Na2Ti3O7 architecture exhibits promising cycling and rate performance as an anode material for sodium-ion batteries. In particular, after 50 charge/discharge cycles at the current loads of 50, 150, 350, and 800 mA/g, the reversible capacities of about 145, 120, 100, and 80 mA∙h/g, respectively, were achieved. Upon prolonged cycling at 350 mA/g, the capacity of approximately 95 mA∙h/g at the 200th cycle was observed with a Coulombic efficiency of almost 100% showing the retention as high as 95.0% initial storage. At last, it is found that residual water in the un-annealed nanotubular Na2Ti3O7 affects its electrochemical properties.

Polymer Carbon Nanodots: A Novel Electrochemiluminophore for Dual Mode Detection of Ferric Ions.

The development of simple and effective dual-mode analytical methods plays crucial regulatory roles in the discrimination of relevant target species, because of their built-in cross reference correction and high accuracy. In this work, a novel polymer carbon nanodots (PCNDs) prepared from a facile one-pot hydrothermal procedure using readily available l-tryptophan and l-phenylalanine as precursors, showed excellent aqueous solubility and blue fluorescence property with a high quantum yield of 29%. Moreover, the PCNDs was demonstrated to be a robust luminophore with electrochemiluminescence (ECL) efficiency of 43% was achieved by using K2S2O8 as a coreactant. The spooling ECL spectroscopy was employed to take insight into excited states responsible for the potential-dependent ECL emissions. Most importantly, when introduced into construction of the fluorescence and ECL dual mode sensing platform, for the first time, the PCNDs displayed prominent performance for the detection of ferric ions (Fe3+). The ferric ions could be quantified ranging from micromolar to millimolar with a detection limit of 0.22 and 5.3 μM, respectively. Such a dual-functional sensing platform also exhibits excellent selectivity, reproducibility and stability. Results from this work indicate that PCNDs showing great promise as a bright luminophore for the fabrication of low-cost, high-performance dual-signal readout platforms for ferric ions determination.

Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes.

A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed—Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of −3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (kap in min−1): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (kapc in min−1) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (kap = 0.0097 min−1 and kapc = 0.012 min−1 (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.

Electrodeposition of CQDs/P-Fe2O3 on carbon cloth for flexible asymmetric supercapacitors

By incorporating the advantages of different materials, the composite material can Preferably strengthen the electrochemical performance of the electrode material. In this paper, CQDs/P-Fe2O3 on carbon cloth (CC) as flexible electrode material was synthesized with one-pot hydrothermal synthesis procedure. The one-dimentional (1D) structure was favorable due to the chemical stability, electrical conductivity, and fast electrochemical kinetics. While the current density is 0.5 A/g, the specific capacitance of the composite reaches 1786.5 F/g. The assembled supercapacitor remains at 91.31% of its initial specific capacitance after 1000 cycles. When the power density is 639.99 W/kg, the energy density is 103.11Wh/kg, and even when the power density is 12800 W/kg, the energy density can reach 44.8 Wh/kg.

Knack behind the high performance CdS/ZnS-NiS nanocomposites: Optimizing synergistic effect between cocatalyst and heterostructure for boosting hydrogen evolution

• A one-step hydrothermal method is developed to synthesize CdS/ZnS-NiS for the first time. • The three components (CdS, ZnS and NiS) are fully combined together at nano-scale. • The optimized CdS/ZnS-NiS exhibits a photocatalytic H 2 evolution rate of 604.4 μmol·h −1 . • Synergistic effect between CdS/ZnS heterostructure and NiS co-catalyst boosts H 2 evolution. Introducing co-catalyst and constructing heterostructure are two of the most promising strategies in improving the photocatalytic H 2 evolution performance of semiconductors. However, it has always been a great challenge to develop a facile and low-cost system to facilitate the highly efficient synergistic effect between co-catalyst and heterostructure. Herein, co-catalyst NiS decorated ZnS/CdS heterostructure (CdS/ZnS-NiS) has been fabricated by using a facile one-pot hydrothermal procedure for the photocatalytic H 2 evolution from water splitting. As a result, CdS, ZnS and NiS contact closely with each other at nano scale to assemble into fluffy porous nanocomposite, the optimized CdS/ZnS-NiS exhibits a high hydrogen evolution rate of 60.44 mmol·h −1 g −1 without the addition of extra noble metal co-catalyst, which is about 22.3 times higher than that of pure CdS and much higher than that of 1% wt Pt decorated CdS/ZnS (52.36 mmol·h −1 g −1 ). One-pot fabrication process allows the formation of intimate contacted interface between different components, contributing to the sufficient exposure of active reaction sites. Moreover, noble-metal-free co-catalyst NiS distributes uniformly in both surface and inner region of porous nanocomposite. The synergistic effect between the intimately contacted heterostructure and co-catalyst boosts the separation and utilization of photogenerated charge carriers, resulting in a dramatically enhanced H 2 evolution ability. This work provides a facile pathway to uniformly introduce noble-metal-free co-catalyst in heterostructure and gives out a paradigm in constructing high active solar energy conversion system.

Facile one pot green synthesis of –NH2 surface functionalized graphene-polymer nanocomposite: Subsequent utilization as stabilizer in pickering emulsions

Simple and cost-effective synthesis of surface functionalized graphene and its nanocomposites with polymers is strongly desirable to further expand their utility. Most of the methods reported till date use separate procedures to reduce the graphene oxide (GO), functionalize the resulting graphene and subsequently prepare the nanocomposite with polymers respectively. In this report, we are utilizing a one-pot hydrothermal synthetic procedure to prepare polymer-graphene nanocomposite through in-situ reduction of GO and amine functionalization of resulting graphene. Polyacryloyl hydrazide (PAHz) possessing hydrazide functional groups is used as the reducing agent to convert the GO to the graphene, subsequently functionalize the resulting graphene with the amino groups and encapsulates the resulting –NH2 functional graphene to prepare the PAHz/rGO nanocomposite. Various characterization techniques including UV-Vis, fluorescence, XPS, HRTEM and DLS is utilized to characterize the nanocomposite. The resulting nanocomposites possessing hydrodynamic size of ~ 40 nm is utilized to stabilize Pickering emulsion based on olive oil/n-decane and water. The resulting Pickering emulsion exhibited excellent stability with proper droplet packing and no sign of creaming till 17 days under ambient conditions suggesting the efficacy of the PAHz/rGO nanocomposite as stabilizing agent, which is superior compared to a number of systems studied in recent literature. Overall, the synthesized nanocomposites with a narrow size distribution can be potentially utilized in a number of useful areas.

One-pot synthesis of BiSbO4/BiOBr nanocomposite with excellent UV-photocatalytic activity

A facile one-pot hydrothermal synthesis procedure and UV-photocatalytic activity of a series of BiSbO4/BiOBr nanocomposites with various BiSbO4-rich contents were first-time reported in this work. The results showed that BiSbO4/BiOBr nanocomposites containing 10-nm BiOBr nanocubes embedded on BiSbO4 nanobundles were obtained readily. For the optimized BiSbO4/BiOBr nanocomposite, the methyl orange photocatalytic removal efficiency under 365-nm UV illumination was 90% after 120 min, pronouncedly higher than that of the pure BiSbO4 sample (22%). A heterogeneous phase junction formed between BiSbO4 nanobundles and embedded BiOBr nanocubes was supposed to be a major factor causing this enhanced photocatalytic activity of the optimized nanocomposite sample. The mechanism of methyl orange photodegradation over BiSbO4/BiOBr nanocomposites containing heterogeneous phase junction was also proposed.

Fast construction of (Fe2O3)x@Ni-MOF heterostructure nanosheets as highly active catalyst for water oxidation

Construction of heterostructure engineered to modulate the electronic structure and enhance conductivity is an effective approach to enhance the performance of materials. The construction of heterostructure electrocatalysts with efficient catalytic activity by combining 2D nanosheet metal organic frameworks (MOFs) with other earth-rich transition metal oxide materials is a compelling study. Herein, a novel (Fe2O3)0.36@Ni-MOF heterostructure nanosheets has been synthesized by a rapid one-pot hydrothermal procedure as an efficient OER catalyst. (Fe2O3)0.36@Ni-MOF exhibited prominent OER property with the overpotential of 230 mV at10 mA cm−2, a small Tafel slope of 66.7 mV dec−1 and ignorable activity decay after 20 h long-term test at 10 mA cm−2. The excellent properties of (Fe2O3)0.36@Ni-MOF nanocomposite could be attribute to the vast amounts of active sites exposed by the nanosheets and ultrasmall size nanoparticles, and the electronic interaction between Fe2O3 and Ni-MOF in the heterostructure. This work presents an attractive tactics for the preparation of heterostructure catalysts with good OER catalytic performance.

Fe3O4@N-porous carbon nano rice/rGO sheet as positive electrode material for a high performance supercapattery

Fe3O4 particles are designed to originate reversible faradaic process and carbon material with a rice-like shape and meso-pore dominated structure is designed to encapsulate the Fe3O4 particles. Synthesized carbon nano rice wrapped Fe3O4 are uniformly anchored on the surface of reduced graphene oxide (rGO) nano sheets in a one-pot facile hydrothermal procedure. A significant amount (13.28 at%) of N is also doped into the carbon nano rice in the hydrothermal process, simultaneously. The synthesized Fe3O4@N-Carbon nano rice/rGO (Fe3O4@N-PCNR/rGO) delivers a high capacity of 495 Cg-1at a current density of 1 Ag-1 and high long-term stability of 70% after 1000 charge-discharge cycles at 10 Ag-1. The Fe3O4@N-Carbon/rGO is utilized as a positive electrode, and synthesized 3D rGO aerogel is employed as a negative electrode to fabricate a supercapattery, which exhibits a wide operating potential window of 1.5 V, a high energy density of 46 W h kg-1 at 750 W kg-1, and even 10 W h kg-1 at an elevated power density of 7500 W kg-1. The supercapattery also performs well in terms of long-life stability with 80% of capacitance retention after 10,000 charge-discharge cycles at 10 Ag-1.

Rational Functionalization Towards Redox-Active TEMPO Stable Free-Radical-Hydrochar Composites.

Although both stable free organic radicals and biomass-derived hydrochars have emerged as appealing, green, multifunctional materials, their association has not been explored. In this study, strength is found to lie in their union, which primarily leads to stable redox-active free-radical-hydrochar composites that can generate unexpected opportunities for the development of advanced metal-free sustainable materials. The composites are obtained by a straightforward green one-pot hydrothermal procedure. The loading of stable free radicals of nitroxide type and their localization is engineered by the nature of the carbohydrate and the reaction status; vigorous reaction parameters promote faster nucleation and growth kinetics of the hydrochar products, leading to a covalent immobilization of redox species on the surface of the carbonaceous microspherical aggregates. The nitroxide free-radical-hydrochar materials demonstrate enhancements in terms of both electrocatalytic activity and capacitive features.

Ternary heterojunction stabilized photocatalyst of Co-TiO2/g-C3N4 in boosting sulfite oxidation during wet desulfurization

Visible light can promote a catalyst to generate a large number of oxidative free radicals. The photocatalysis of sulfite oxidation is an efficient and economical approach for reclaiming wet desulfurization byproducts. In the present study, a cost-effective photocatalyst with a low metal concentration, namely Co-TiO2/g-C3N4 (CTO/CN), was synthesized using a simplified one-pot hydrothermal procedure. The structure and characteristics of this photocatalyst were assessed using various characterization methods. The as-prepared CTO/CN exhibited enhanced photocatalytic activities for the oxidation of MgSO3, which was 11-fold higher than that of the uncatalyzed benchmark. Under irradiation, ternary heterojunction photocatalyst accelerated the charge transfer, reduced the band gap and enhanced the production of strong oxidizing species (·O2−, ·OH and h+), which promote the formation of the ·SO5− radical, the active species in the MgSO3 oxidation. The as-prepared CTO/CN increased the critical mass concentration of magnesium sulfate from 10% to 19.9%, which reduced the recovery cost of magnesium sulfate. This paper proposes an environmentally friendly strategy for improving the overall performance of wet desulfurization with low cobalt doping levels for photocatalytic oxidation reactions under visible light.