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A metal–organic framework (MOF) is a highly porous material with abundant redox capacitive sites for intercalation/de-intercalation of charges and, hence, is considered promising for electrode materials in supercapacitors. In addition, dopants can introduce defects and alter the electronic structure of the MOF, which can affect its surface reactivity and electrochemical properties. Herein, we report a copper-doped iron-based MOF (Cu@Fe-MOF/NF) thin film obtained via a simple drop-cast route on a 3D-nickel foam (NF) substrate for the supercapacitor application. The as-deposited Cu@Fe-MOF/NF electrodes exhibit a unique micro-sized bipyramidal structure composited with nanoparticles, revealing a high specific capacitance of 420.54 F g−1 at 3 A g−1 which is twice compared to the nano-cuboidal Fe-MOF/NF (210 F g−1). Furthermore, the asymmetric solid-state (ASSSC) supercapacitor device, derived from the assembly of Cu@Fe-MOF/NFǁrGO/NF electrodes, demonstrates superior performance in terms of energy density (44.20 Wh.kg−1) and electrochemical charge–discharge cycling durability with 88% capacitance retention after 5000 cycles. This work, thus, demonstrates a high potentiality of the Cu@Fe-MOF/NF film electrodes in electrochemical energy-storing devices. [ABSTRACT FROM AUTHOR]

Ammonium toxicity is a significant source of pollution from industrial civilization that is disrupting the balance of natural systems, adversely affecting soil and water quality, and causing several environmental problems that affect aquatic and human life, including the strong promotion of eutrophication and increased dissolved oxygen consumption. Thus, a cheap catalyst is required for power generation and detoxification. Herein, compost soil is employed as a novel electrocatalyst for ammonium degradation and high-power generation. Moreover, its effect on catalytic activity and material performances is systematically optimized and compared by treating it with various reducing agents, including potassium ferricyanide, ferrocyanide, and manganese dioxide. Ammonium fuel was supplied to the compost soil ammonium fuel cell (CS-AFC) at concentrations of 0.1, 0.2, and 0.3 g/mL. The overall results show that ferricyanide affords a maximum power density of 1785.20 mW/m2 at 0.2 g/mL fuel concentration. This study focuses on high-power generation for CS-AFC. CS-AFCs are sustainable for many hours without any catalyst deactivation; however, they need to be refueled at regular intervals (every 12 h). Moreover, CS-AFCs afford the best performance when ferricyanide is used as the electron acceptor at the cathode. This study proposes a cheap electrocatalyst and possible solutions to the more serious energy generation problems. This study will help in recycling ammonium-rich wastewaters as free fuel for running CS-AFC devices to yield high-power generation with reducing agents for ammonium fuel cell power applications. [ABSTRACT FROM AUTHOR]

Monitoring phenolic compounds is critical in the environmental, food, and medical sectors. Among many recent advanced detection platforms, laccase-based biosensing platforms gave very rapid, effective, online, and in situ sensing of phenolic compounds. In laccase-based biosensors, laccase immobilization techniques have a vital role. However, a detailing of the advancements in laccase immobilization techniques employed in laccase-based biosensors is lacking in the literature. Thus, in this review, we assessed how the nano-immobilization techniques shaped the laccase biosensing platforms. We discussed novel developments in laccase immobilization techniques such as entrapment, adsorption, cross-linking, and covalent over new nanocomposites in laccase biosensors. We made a comprehensive assessment based on the current literature for future perspectives of nano-immobilized laccase biosensors. We found the important key areas toward which future laccase biosensor research seems to be heading. These include 1. A focus on the development of multi-layer laccase over electrode surface, 2. The need to utilize more covalent immobilization routes, as they change the laccase specificity toward phenolic compounds, 3. The advancement in polymeric matrices with electroconductive properties, and 4. novel entrapment techniques like biomineralization using laccase molecules. Thus, in this review, we provided a detailed account of immobilization in laccase biosensors and their feasibility in the future for the development of highly specific laccase biosensors in industrial, medicinal, food, and environmental applications. [ABSTRACT FROM AUTHOR]

This study explored the potential of abundantly available sodium lignosulfonate (LS) as a reducer and fabricating agent in preparing silver nanoparticles (LS–Ag NPs). The operational conditions were optimized to make the synthesis process simpler, rapid, and eco-friendly. The prepared LS–Ag NPs were analyzed via UV–Vis spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy. Results demonstrated that LS–Ag NPs were of crystalline structure, capped with LS constituents, and spherical in shape with a size of approximately 20 nm. Under optimized conditions, LS–Ag NPs exhibited significant photocatalytic activity in Reactive Yellow 4G degradation. The effects of photocatalyst (LS–Ag NPs) dosage, dye concentration, and its reusability for dye degradation were studied to make the process practically applicable in textile wastewater treatment. Additionally, the synthesized LS–Ag NPs displayed significant free radical scavenging against 2-diphenyl-1-picrylhydrazyl (DPPH) with an IC50 value of (50.2 ± 0.70 µg/mL) and also exhibited antidiabetic activity in terms of inhibition in the activity of carbohydrate-degrading marker enzyme α-glucosidase with an IC50 value of (58.1 ± 0.65 µg/mL). LS–Ag NPs showed substantial antibacterial potential against pathogenic strains, namely E. coli and S. aureus. In conclusion, LS–Ag NPs can be a reliable and eco-friendly material for their possible application in the treatment of dye-containing wastewater and have a great perspective in the biomedical and pharmaceutical sectors. [ABSTRACT FROM AUTHOR]

We are reporting on the impact of air annealing temperatures on the physicochemical properties of electrochemically synthesized cadmium selenium telluride (CdSe0.6Te0.4) samples for their application in a photoelectrochemical (PEC) solar cell. The CdSe0.6Te0.4 samples were characterized with several sophisticated techniques to understand their characteristic properties. The XRD results presented the pure phase formation of the ternary CdSe0.6Te0.4 nanocompound with a hexagonal crystal structure, indicating that the annealing temperature influences the XRD peak intensity. The XPS study confirmed the existence of Cd, Se, and Te elements, indicating the formation of ternary CdSe0.6Te0.4 compounds. The FE-SEM results showed that the morphological engineering of the CdSe0.6Te0.4 samples can be achieved simply by changing the annealing temperatures from 300 to 400 °C with intervals of 50 °C. The efficiencies (ƞ) of the CdSe0.6Te0.4 photoelectrodes were found to be 2.0% for the non-annealed and 3.1, 3.6, and 2.5% for the annealed at 300, 350, and 400 °C, respectively. Most interestingly, the PEC cell analysis indicated that the annealing temperatures played an important role in boosting the performance of the photoelectrochemical properties of the solar cells. [ABSTRACT FROM AUTHOR]

Memristive systems can provide a novel strategy to conquer the von Neumann bottleneck by evaluating information where data are located in situ. To meet the rising of artificial neural network (ANN) demand, the implementation of memristor arrays capable of performing matrix multiplication requires highly reproducible devices with low variability and high reliability. Hence, we present an Ag/CuO/SiO2/p-Si heterostructure device that exhibits both resistive switching (RS) and negative differential resistance (NDR). The memristor device was fabricated on p-Si and Indium Tin Oxide (ITO) substrates via cost-effective ultra-spray pyrolysis (USP) method. The quality of CuO nanoparticles was recognized by studying Raman spectroscopy. The topology information was obtained by scanning electron microscopy. The resistive switching and negative differential resistance were measured from current–voltage characteristics. The results were then compared with the Ag/CuO/ITO device to understand the role of native oxide. The interface barrier and traps associated with the defects in the native silicon oxide limited the current in the negative cycle. The barrier confined the filament rupture and reduced the reset variability. Reset was primarily influenced by the filament rupture and detrapping in the native oxide that facilitated smooth reset and NDR in the device. The resistive switching originated from traps in the localized states of amorphous CuO. The set process was mainly dominated by the trap-controlled space-charge-limited; this led to a transition into a Poole–Frenkel conduction. This research opens up new possibilities to improve the switching parameters and promote the application of RS along with NDR. [ABSTRACT FROM AUTHOR]