Hybrid supercapacitors using metal-organic framework derived nickel-sulfur compounds.

HYPOTHESIS: Metal-organic frameworks (MOFs) are highly suitable precursors for supercapacitor electrode materials owing to their high porosity and stable backbone structures that offer several advantages for redox reactions and rapid ion transport. EXPERIMENTS: In this study, a carbon-coated Ni9S8 composite (Ni9S8@C-5) was prepared via sulfuration at 500 ℃ using a spherical Ni-MOF as the sacrificial template. FINDING: The stable carbon skeleton derived from Ni-MOF and positive structure-activity relationship due to the multinuclear Ni9S8 components resulted in a specific capacity of 278.06 mAh·g-1 at 1 A·g-1. Additionally, the hybrid supercapacitor (HSC) constructed using Ni9S8@C-5 as the positive electrode and the laboratory-prepared coal pitch-based activated carbon (CTP-AC) as the negative electrode achieved an energy density of 69.32 Wh·kg-1 at a power density of 800.06 W·kg-1, and capacity retention of 83.06 % after 5000 cycles of charging and discharging at 5 A·g-1. The Ni-MOF sacrificial template method proposed in this study effectively addresses the challenges associated with structural collapse and agglomeration of Ni9S8 during electrochemical reactions, thus improving its electrochemical performance. Hence, a simple preparation method is demonstrated, with broad application prospects in supercapacitor electrodes.

An electrochemical aptasensor based on silver-thiolated graphene for highly sensitive detection of Pb2.

The presence of lead ions (Pb2+) in the environment not only leads to environmental contamination but also poses a significant risk to public health through their migration into food and drinking water. Therefore, the development of rapid and effective techniques for detection of trace amounts of Pb2+ is crucial for safeguarding both the environment and biosafety. In this study, an aptamer-based electrochemical sensor was developed for specific detection of Pb2+ by modifying a polylysine (PLL) coated silver-thiolated graphene (Ag-SH-G) nanocomposite (PLL/Ag-SH-G) on the surface of a glassy carbon electrode, which was further modified with gold nanoparticles (AuNPs) for attachment of aptamers (Apt) that specifically recognized Pb2+. The Ag-SH-G particles were synthesized using a one-step in situ method, resulting in significantly enhanced electrochemical properties upon incorporating Ag nanoparticles into the PLL/Ag-SH-G composite. Coating of the covalently or no-covalently bonded Ag-SH-G particles with PLL provides an excellent supporting matrix, facilitating the assembly of AuNPs and a thiol-modified aptamer for Pb2+. Under optimized conditions, Apt/AuNPs/PLL/Ag-SH-G/GCE exhibited excellent sensing performance for Pb2+ with a wide linear response range (10-1000 nM), a low detection limit (0.047 nM) and extraordinary selectivity. The sensor was employed and satisfactory results were obtained in river water, soil and vegetable samples for the detection of Pb2+.

Ultrasensitive, Label-Free Voltammetric Detection of Dibutyl Phthalate Based on Poly-l-lysine/poly(3,4-ethylenedioxythiophene)-porous Graphene Nanocomposite and Molecularly Imprinted Polymers.

Development of an efficient technique for accurate and sensitive dibutyl phthalate (DBP) determination is crucial for food safety and environment protection. An ultrasensitive molecularly imprinted polymers (MIP) voltammetric sensor was herein engineered for the specific determination of DBP using poly-l-lysine/poly(3,4-ethylenedioxythiophene)/porous graphene nanocomposite (PLL/PEDOT-PG) and poly(o-phenylenediamine)-imprinted film as a label-free and sensing platform. Fabrication of PEDOT-PG nanocomposites was achieved through a simple liquid-liquid interfacial polymerization. Subsequently, poly-l-lysine (PLL) functionalization was employed to enhance the dispersibility and stability of the prepared PEDOT-PG, as well as promote its adhesion on the sensor surface. In the presence of DBP, the imprinted poly(o-phenylenediamine) film was formed on the surface of PLL/PEDOT-PG. Investigation of the physical properties and electrochemical behavior of the MIP/PLL/PEDOT-PG indicates that the incorporation of PG into PEDOT, with PLL uniformly wrapping its surface, significantly enhanced conductivity, carrier mobility, stability, and provided a larger surface area for specific recognition sites. Under optimal experimental conditions, the electrochemical response exhibited a linear relationship with a logarithm of DBP concentration within the range of 1 fM to 5 µM, with the detection limit as low as 0.88 fM. The method demonstrated exceptional stability and repeatability and has been successfully applied to quantify DBP in plastic packaging materials.

An Effective Strategy to Synthesize Well-Designed Activated Carbon Derived from Coal-Based Carbon Dots via Oxidation before Activation with a Low KOH Content as Supercapacitor Electrodes.

The development of coal-based activated carbon for supercapacitors provides a robust and effective approach toward the clean and efficient use of coal, and it also offers high-quality and low-cost raw materials for energy storage devices. However, the one-step activation method for preparing coal-based activated carbon has problems, such as difficulty in introducing surface-functional groups and high KOH dosage. In our work, activated carbon was prepared through an effective strategy of oxidation and KOH activation with a low KOH content by employing coal-based carbon dots as raw material. The influence of temperature during the KOH activation of carbon dots on a specific surface area, pore structure, and various quantities and types of surface-functional groups, as well as on the electrochemical performance of supercapacitors, was systematically studied. The as-prepared sample, with the alkali-carbon ratio of 0.75, processes a large specific surface area (1207 m2 g-1) and abundant surface-functional groups, which may provide enormous active sites and high wettability, thus bringing in high specific capacitance and boosted electrochemical performances. The oxygen and nitrogen content of the activated carbon decreases while the carbon content increases, and the activation temperature also increases. The as-prepared activated carbon reaches the highest specific capacitance of 202.2 F g-1 in a 6 M KOH electrolyte at a current density of 10 A g-1. This study provides new insight into the design of high-performance activated carbon and new avenues for the application of coal-based carbon dots.

Entropy-Stabilized Layered K0.6Ni0.05Fe0.05Mg0.05Ti0.05Mn0.725O2 as a High-Rate and Stable Cathode for Potassium-Ion Batteries.

Mn-based layered oxides have been considered the most promising cathode candidates for cost-effective potassium-ion batteries (PIBs). Herein, equiatomic constituents of Ni, Fe, Mg, and Ti have been introduced into the transition metal layers of Mn-based layered oxide to design a high-entropy K0.6Ni0.05Fe0.05Mg0.05Ti0.05Mn0.0725O2 (HE-KMO, S = 1.17R). Consequently, the experimental results manifest that the layered structure of HE-KMO is more stable than conventional low-entropy K0.6MnO2 (LE-KMO, S = 0.66R) during successive cycling and even upon exposure to moisture. Diffraction and electrochemical measurements reveal that HE-KMO undergoes a solid-solution mechanism, contrary to the multistage phase transition processes typically exemplified in K0.6MnO2. Benefiting from the stabilized high-entropy layered framework and the solid-solution K+ storage mechanism, the entropy-stabilized HE-KMO not only demonstrates exceptional rate capability but also shows excellent cyclic stability. Notably, a capacity retention ratio of 86% after 3000 cycles can still be sustained at a remarkable current density of 5000 mA g-1.

Ultrasensitive Electrochemical Aptasensing of Malathion Based on Hydroxylated Black Phosphorus/Poly-L-Lysine Composite.

A highly sensitive unlabeled electrochemical aptasensor based on hydroxylated black phosphorus/poly-L-lysine (hBP/PLL) composite is introduced herein for the detection of malathion. Poly-L-lysine (PLL) with adhesion and coating properties adhere to the surface of the nanosheets by noncovalent interactions with underlying hydroxylated black phosphorus nanosheets (hBP) to produce the hBP/PLL composite. The as-synthesized hBP/PLL composite bonded to Au nanoparticles (Au NPs) firmly by assembling and using them as a substrate for the aptamer with high specificity as a probe to fabricate the sensor. Under optimal conditions, the linear range of the electrochemical aptasensor was 0.1 pM~1 µM, and the detection limit was 2.805 fM. The electrochemical aptasensor has great selectivity, a low detection limit, and anti-interference, which has potential application prospects in the field of rapid trace detection of pesticide residues.

Preparation of pyrolysis products by catalytic pyrolysis of poplar: Application of biochar in antibiotic wastewater treatment.

Poplar waste is acted as feedstock to produce renewable biofuel and green chemical by catalytic pyrolysis using ferric nitrate and zinc chloride as additive. The additive contributes to the generation of furfural in bio-oil. Additive promotes the generation of H2 and inhibits the generation of CO with bio-gas heating value of 12.16 MJ (Nm3)-1. Biochar exists ZnO and Fe3O4 with large surface area, which could be used as absorbent and photocatalyst for tetracycline and ciprofloxacin removal. The tetracycline and ciprofloxacin adsorption amount of biochar are 316.41 and 255.23 mg g-1 respectively. While the photocatalytic degradation removal of the tetracycline and ciprofloxacin is close to 100%. The adsorption and photocatalytic degradation mechanism are investigate and analyzed using the density functional theory and electron paramagnetic resonance analysis. Biochar can be quickly recycled and regenerated after use. Besides, biochar can be used in lithium ion battery industry for energy storage, which specific capacity is 535 mAh g-1.

Fixating lead in coal gangue with phosphate using phosphate-dissolving bacteria: Phosphorus dissolving characteristics of bacteria and adsorption mechanism of extracellular polymer.

Controlling and preventing lead pollution is currently the focus of environmental remediation. Coal gangue contains large quantities of lead, and its environmental impact cannot be ignored. This study investigated the tolerance of Stenotrophomonas maltophilia (YZ-1 train) to lead ion and its fixation effect on lead in coal gangue. The fixation mechanism of lead ions by using the YZ-1 train was studied with CaHPO4 and Ca3(PO4)2. The tolerance mechanism and fixation characteristics of the three bacterial extracellular polymers and cell components to lead were analyzed. The results show that the YZ-1 train had a strong resistance to lead ions. The amount of lead released from coal gangue can be reduced by up to 91.1% upon treatment with the YZ-1 train, which can dissolve phosphate minerals to form stable hydroxyapatite (Pb5(PO4)3(OH)) and pyromorphite (Pb5(PO4)3Cl) with lead ions. Tryptophan and tyrosine from cellular components and extracellular polymers with loosely and tightly bound proteins are the main participants in the fixation of lead ions. The by-products of soluble microbes affect the fixation of lead ions in soluble extracellular polymers. The carboxylic acids and carboxylates secreted by bacteria are involved in the adsorption and fixation of lead ions.

Construction of a type-II BiVO4/BiOI heterojunction for efficient photoelectrocatalytic degradation of ß-naphthol and coal gasification wastewater under visible-light irradiation.

Herein, a novel type-II BiVO4/BiOI (BVOI) heterojunction electrode material was successfully fabricated by using a facile two-step electrodeposition approach. The experimental results revealed that BiOI nanosheets were deposited onto the surface of BiVO4 particles successfully, with the special morphology providing more active sites, which was beneficial to the improvement of PEC performance. According to the electrochemical performance tests, it could be observed that the construction of a heterojunction effectively promoted the separation of photoinduced electron-hole pairs and increased the transfer rate of surface charges. Under visible-light irradiation, the BVOI-300 photoanode possessed the highest PEC ß-naphthol degradation rate at pH = 7, which approximately reached 82%, whose corresponding kinetic constant was 1.4 and 1.5 times higher than those of pure BiVO4 and BiOI. After five cycles, the degradation rate still remained at 64.61%. The band structure of the BVOI electrode was deduced, and the PEC mechanism of the BVOI electrode was investigated through the radical trapping quenching experiments and ESR test, which indicated that the ˙OH, h+ and ˙O2- radicals were crucial active species in the PEC ß-naphthol degradation process. For the BVOI-300 working electrode, the TOC content of coal gasification wastewater (CGW) decreased from 94.44 to 54.4 mg L-1, and the removal rate reached 42.4%. GC-MS was used to identify the organic components of coal gasification wastewater, which was expected to provide reference for remedying actual gasification wastewater containing refractory organic pollutants and offer a new development direction for the treatment of actual coal chemical wastewater.

Neuroprotective effects of PRG on Aß25-35-induced cytotoxicity through activation of the ERK1/2 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Phylloporia ribis (Schumach:Fr.)Ryvarden is a genus of needle Phellinus medicinal fungi, parasitic on the living rhizomes of hawthorn and pear trees. As a traditional Chinese medicine, Phylloporia ribis was used in folklore for long-term illness, weakness and memory loss in old age. Previous studies have shown that polysaccharides from Phylloporia ribis (PRG) significantly promoted synaptic growth in PC12 cells in a dose-dependent manner, exhibiting "NGF"-like neurotrophic activity. Aß25-35 damage to PC12 cells produced neurotoxicity and decreased cell survival, and PRG reduced the apoptosis rate, suggesting that PRG has neuroprotective effects. The studies confirmed that PRG had the potential to be a neuroprotective agent, but its neuroprotective mechanism remained unclear. AIM OF THE STUDY: We aimed to elucidate the neuroprotective effects of PRG in an Aß25-35-induced Alzheimer's disease (AD) model. MATERIALS AND METHODS: Highly-differentiated PC12 cells were treated with Aß25-35 (AD model) and PRG, and were assessed for cellular apoptosis, inflammatory factors, oxidative stress, and kinase phosphorylation. RESULTS: The results showed that the PRG groups effectively inhibited the neurotoxicity, mainly manifested by inhibiting mitochondrial oxidative stress, attenuating neuroinflammatory responses, and improving mitochondrial energy metabolism, eventually resulting in higher cell survival. The expression of p-ERK, p-CREB and BDNF proteins was increased in the PRG groups compared to the model group, which confirmed that PRG reversed the inhibition of the ERK pathway. CONCLUSION: We provide evidence for neuroprotection conferred by PRG and its mechanism by inhibiting ERK1/2 hyper-phosphorylation, prevention of mitochondrial stress, and subsequent prevention of apoptosis. The study highlights PRG as a promising candidate with neuroprotective effects, the potential of which can be harnessed for identifying novel therapeutic targets.

3D chrysanthemum-like g-C3N4/TiO2 as an efficient visible-light-driven Z-scheme hybrid photocatalyst for tetracycline degradation.

Utilization of a solar-driven semiconductor as a photocatalyst to degrade antibiotic pollutants is a feasible and environmentally friendly technology. In this paper, 3D chrysanthemum-like g-C3N4/TiO2 as a visible-light-driven hybrid photocatalyst with a Z-scheme heterostructure was firstly synthesized by the in situ hydrothermal synthesis method. Experiments proved that this 3D chrysanthemum-like g-C3N4/TiO2 had better degradation performance toward tetracycline than TiO2 and g-C3N4. In particular, when optimized g-C3N4/TiO2-2 was applied for tetracycline removal (200 ml, 10 mg L-1), the corresponding degradation efficiency could reach nearly 100% within 60 min. The improved photocatalytic activity was the result of better utilization of the heterostructure-induced visible light, more efficient charge transfer in the Z-scheme heterojunction as well as stronger redox capability. The Z-scheme degradation mechanism was supported by the trapping experiments of active species and ESR radical detection, and the whole photocatalytic process was controlled by the combined action of ˙O2-, h+ and ˙OH radicals. This study may be beneficial for the design of more efficient sunlight-driven hybrid photocatalysts and their applications in wastewater treatment.

Stable lithium metal anode enabled by in situ formation of a Li3N/Li-Bi alloy hybrid layer.

A hybrid protective layer containing a Li3N and Li-Bi alloy is fabricated on a Li-metal anode as an artificial SEI layer to guide dendrite-free Li deposition. Noteworthily, the hybrid interface could not only facilitate homogeneous Li plating but also provide rapid Li+ transportation, enabling a long-term stability of ∼2400 h at 0.5 mA cm-2 with a low steady overpotential of 10 mV.

Foldable and wearable supercapacitors for powering healthcare monitoring applications with improved performance based on hierarchically co-assembled CoO/NiCo networks.

Small-scale and high-performance energy storage devices have drawn tremendous attention with their portable, lightweight, and multi-functionalized features. Here, we present a foldable supercapacitor with affordable flexibility by adopting a developed design and electrode material system as a way to extend usability. Notably, to resolve the limited energy density of conventional capacitors, we successfully synthesize the CoO/NiCo-layered double hydroxide (LDH) core-shell nanostructure on Ni framework as a cathode material. Further, glucose-based activated carbon (GBAC) is utilized for the anode. The CoO/NiCo-LDH electrodes exhibited a high specific capacitance of âˆ¼284.8 mAh g-1 at 1 A g-1, and GBAC delivers a high specific capacitance of âˆ¼166 F g-1 at 1 A g-1. In the following, the combinatorial integration of these materials enabled the asymmetric supercapacitor (ASC) to increase the energy density by enhancing the capacitance and the voltage window, in which a hydrogel-based electrolyte was facilitated for the foldable and wearable capability. The energy density of the ASC device was âˆ¼24.9 Wh kg-1 at a power density of âˆ¼779.5 W kg-1 with a voltage window of âˆ¼1.6 V. As demonstrated, a self-powered energy source was demonstrated by a serially connected multi-ASC device with a help of a commercial solar cell, which was employed for powering wearable healthcare monitoring devices, including personal alarms for patients and recording the human body's electrical signals. The present work offers a viable approach to preparing potential candidates for high-performance electrodes of supercapacitors with deformable configurations to extend the powering capability of other electronic devices with physical functionalities used in wearable electronics.

Label-Free Aptasensor for Detection of Fipronil Based on Black Phosphorus Nanosheets.

A label-free fipronil aptasensor was built based on Polylysine-black phosphorus nanosheets composition (PLL-BPNSs) and Au nanoparticles (AuNPs). A PLL-BP modified glassy carbon electrode (GCE) was fabricated by combining BP NSs and PLL, which included a considerable quantity of -NH2. Au nanoparticles (AuNPs) were placed onto the GCE, and PLL-BPNSs bonded to Au NPs firmly by assembling. The thiolated primers were then added and fixed using an S-Au bond, and competitive binding of the fipronil aptamer was utilized for fipronil quantitative assessment. The sensor's performance was evaluated using differential pulse voltammetry (DPV) method. The linear equation is ΔI (µA) = 13.04 logC + 22.35, while linear correlation coefficient R2 is 0.998, and detection limit is 74 pg/mL (0.17 nM) when the concentration of fipronil is 0.1 ng/mL-10 µg/mL. This aptasensor can apply to quantitative detection of fipronil.

Preparation of valuable pyrolysis products from poplar waste under different temperatures by pyrolysis: Evaluation of pyrolysis products.

Poplar waste is used as feedstock to prepare valuable pyrolysis products by pyrolysis under different temperature. The bio-oil is rich in aldehyde with the maximum relative content of 47.15%, which has potential application in chemical industries. Pyrolysis temperature has significantly influenced the composition and heating value of bio-gas. The maximum heating value of bio-gas is 14.56 MJ/Nm3. Biochar is used as an adsorbent to adsorb Ag+ from aqueous solution with the adsorption capacity of 76.09 mg/g. Biochar forms the value-added Ag-Biochar composite by reduction after adsorption Ag+. While, Ag-Biochar composite can be used as catalyst for methyl orange removal with the maximum removal of 94.08%. Ag-Biochar composite is also used as lithium ion battery cathode material for energy storage with the specific capacity of 345 mAh/g. Besides, preliminary economic analysis is used to evaluate the economics of pyrolysis process with the total annual revenue of $115, 725/year.

Reclamation of waste coal gangue activated by Stenotrophomonas maltophilia for mine soil improvement: Solubilizing behavior of bacteria on nutrient elements.

The coal gangue has occupied the farmland and caused severe pollution to the surrounding environment, which was discharged with vast amount as a by-product of coal mining and washing. A sustainable and ecological microorganism activation method was proposed to disposal coal gangue as mineral fertilizer. A Stenotrophomonas maltophilia YZ1 bacteria was separated and found to be useful in solubilizing nutrient elements in coal gangue. The contents of available P, available K and available Si in the treated coal gangue reached 278.4 mg/kg, 1305.3 mg/kg and 522.7 mg/kg, respectively. The YZ1 bacteria dissolved the minerals of monetite (CaHPO4), muscovite and annite by the organic acids, which were the metabolism product of YZ1 bacteria. The solubilizing mechanisms of phosphate minerals included the release of protic and the chelation of organic acid with calcium. The microbial activation method can provide nutrient elements for soil, which may realize the reclamation of coal gangue in a harmless way.

Effect of BaTiO3 powder as an additive in perovskite films on solar cells.

Perovskite solar cells (PSCs) are considered to be ideal energy devices, where perovskite-type organic metal halides act as light-absorbing materials. In PSCs, the photoexcitons are extracted and separated to afford high photoelectric conversion efficiency under the action of the built-in electric field (E bi). However, the current challenge is that a low E bi cannot provide a sufficient driving force to separate photonic excitons, which causes the captured charges to escape from the deep energy-level defect state. Here, the ferroelectric material barium titanate (BaTiO3) was directly introduced into the perovskite precursor solution to reduce the defection density (to 8.58 × 1017 cm-3) in PSCs and promote the separation of photoexcitons. Furthermore, the addition of BaTiO3 improved the quality of the perovskite film and significantly increased the photoelectric performance after the polarization treatment. This is mainly attributed to the residual polarization electric field generated by ferroelectric polarization, which increased the E bi of the PSCs and the width of the depletion layer and inhibited the non-radiative recombination of carriers. This work provides a possibility to design and develop optoelectronic devices with high-efficiency optoelectronic response behavior.

A Simple Route to Produce Highly Efficient Porous Carbons Recycled from Tea Waste for High-Performance Symmetric Supercapacitor Electrodes.

High-performance porous carbons derived from tea waste were prepared by hydrothermal treatment, combined together with KOH activation. The heat-treatment-processed materials possess an abundant hierarchical structure, with a large specific surface of 2235 m2 g-1 and wetting-complemental hydrophilicity for electrolytes. In a two-electrode system, the porous carbon electrodes' built-in supercapacitor exhibited a high specific capacitance of 256 F g-1 at 0.05 A g-1, an excellent capacitance retention of 95.4% after 10,000 cycles, and a low leakage current of 0.014 mA. In our work, the collective results present that the precursor crafted from the tea waste can be a promising strategy to prepare valuable electrodes for high-performance supercapacitors, which offers a practical strategy to recycle biowastes into manufactured materials in energy storage applications.

High-efficiency removal of lead/cadmium from wastewater by MgO modified biochar derived from crofton weed.

The adsorption performance and mechanisms of Pb2+ and Cd2+ in wastewater using MgO modified biochar derived from crofton weed (MBCW600) are investigated. The Pb2+ and Cd2+ adsorption capacities of MBCW600 by the Hill model reach 384.08 mg/g and 207.02 mg/g, respectively, which is larger than that of original biochar. Pb2+ could be more easily captured by MBCW600 compared to Cd2+ in the multimetal system. Mg2+ contributes to Pb2+ and Cd2+ adsorption among coexisting cations. The exhausted MBCW600 could be well regenerated by simple method after use. The adsorption mechanism study indicates that Pb2+ and Cd2+ removal are primary contributed to mineral precipitation and ion exchange. The effective treatment volumes of Pb2+ and Cd2+ wastewater achieve 3050 mL and 2150 mL in the fixed-bed column experiment, respectively. Therefore, MBCW600 presents remarkable adsorption capability, excellent recoverability and large throughput, which shows the potential application in future treatment of wastewater containing heavy metal.