Creating electrode materials that provide both high capacitance, rapid charge-discharge response, and longevity is a challenge for advanced supercapacitors. A synergistic Ag2S-NiO composite electrode is rationally constructed in this work to address NiO's intrinsic conductivity limitation while maintaining its robust pseudocapacitive properties. By incorporating highly conductive Ag2S with redox-active NiO, the composite improves electron transport, ion diffusion, and charge-transfer kinetics. An optimum mass ratio of Ag2S: NiO = 1:1 is shown to yield the best results, with Ag2S as the best conductor and NiO as the best source of faradaic redox sites. Compared with single-component electrodes, the electrochemical performance of the Ag2S-NiO electrode is much enhanced. Consequently, the optimized Ag2S/NiO electrode exhibits a high specific capacitance of 830Fg-1 at 1Ag-1 in the three-electrode setup, demonstrating strong intrinsic charge-storage capabilities. The composite, when assembled into a practical two-electrode device, has a capacitance of 172Fg-1 at 1Ag-1 and a high energy density of 61Whkg-1 at a power density of 3927Wkg-1. Moreover, the electrode exhibits a long cycling life, with 86.3% of the original capacitance remaining after 5000 charge-discharge cycles at 6 Ag-1. This improvement is explained by the close interfacial contact between Ag2S and NiO, which facilitates synergistic charge storage, reduces internal resistance, and stabilizes repeated redox reactions. These findings demonstrate that the Ag2S-NiO asymmetric architecture is an excellent electrode for supercapacitor applications.

Metal oxides have been widely studied as an efficient and robust electrode material for supercapacitors for a couple of decades due to their affordability, high capacitance, multiple oxidation states, pseudocapacitive nature, and excellent redox activity. In this paper, a SnO2-MnO2 hierarchical nanostructure (HNS) composite has been developed via a cost-effective and straightforward hydrothermal reaction. FESEM and TEM analysis revealed flower-like and nanowire-like morphologies for SnO2 and MnO2, respectively(,) with highly pure, crystalline tetragonal structure. The average size of SnO2 microflowers and MnO2 nanorods is 1.5 mu m and 2.3 mu m. The chemical composition and oxidation states of the samples were investigated using Energy-Dispersive X-ray (EDX) and X-ray Photoelectron Spectroscopy (XPS), specifying the adequate formation of the SnO2-MnO2 HNS composite. The surface area and pore analysis of the samples reveal that the SnO2-MnO2 HNS composite yields the highest BET surface area of 62.93 m(2)/g with mesoporous features centered at similar to 9 nm. Remarkably, at a low current rate of 1 A/g, the SnO2-MnO2 HNS composite achieved a high capacitance of 520 F/g as compared to pure SnO2 and MnO2 in a three-electrode mode assembly at identical conditions. The emergence of heterointerfaces enhanced the capacitance of the composite by providing more surface area for charge transfer and storage at the electrode/electrolyte interface. An asymmetric hybrid supercapacitor (HASC) was constructed utilizing two pseudocapacitive electrode materials: a SnO2-MnO2 HNS composite as the anode and FeSe2 as the cathode, represented as SnO2-MnO2||FeSe2. The fabricated HASC attained a high specific capacitance of 111 F/g, a high energy density of 44.5 Wh/kg, and a power density of 852 W/kg at 1 A/g. At higher current rates, the power density extends to 4153 W/kg, with an energy density of 15 Wh/kg. Similarly, notable stability was observed, with 93.5 % capacitance retention after 10,000 cycles during HASC assembly. Therefore, metal oxides are extensively explored as electrode materials for supercapacitors, and their superiority remains a top priority for researchers and engineers in the design of viable and renewable energy technologies.

In order to achieve efficient degradation of methylene blue (MB), this study proposes a new photoelectrochemical synergistic degradation technology. The combination of electrochemical catalysis and photocatalysis provides an effective method for the efficient degradation of MB. Zinc oxide/porous boron-doped diamond (ZnO/PBDD/Si) composites were successfully prepared by microwave plasma chemical vapor deposition (MPCVD), magnetron sputtering, and the hydrothermal method. The structural characteristics, electrochemical properties, and degradation efficiency of the composite electrode were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD), contact angle measurement, electron paramagnetic resonance (EPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results show that a layer of zinc oxide nanorods is uniformly and densely grown on the surface of PBDD/Si, and the composite electrode is successfully prepared, and the electrochemical performance is improved. The photoelectrocatalytic degradation of MB showed that the ZnO/PBDD/Si composite electrode had the most significant effect on the degradation of MB under the photoelectric synergistic effect. The degradation efficiency reached 99.8% within 25 minutes, and the degradation efficiency was greatly improved. It shows high degradation efficiency, and can be effectively applied to the field of dye wastewater treatment.

Cavitation is one of the major effects of UAL, associated with a variety of phenomena and physical aspects such as chemical, mechanical, and thermal. Cavitation, categorized as an unconventional metal extraction technique, has lately been brought into the field of extractive metallurgy. The past decade has been marked by fundamental advances in leaching efficiencies and reduced reagent consumption with fast reaction kinetics. However, it needs further improvement for carbon neutrality and a sustainable environment, which could be achieved through the enhanced cavitation mechanism. Therefore, the current review focuses on the latest frontiers of conventional and unconventional leaching techniques, with the addition of hydrodynamic and ultrasound-based cavitation systems. By combining the two systems, we may reduce the processing time, energy, and reagents needed to increase the leaching rates of the target metals from various resources on a large scale. This study also observed a resurgence in this field through in-depth discussions on key parameters such as frequency, power, time, temperature, and particle size using kinetic models. Our study found that the particle size, agitation rate, and standing wave formation during UAL operation attract bare attention, which hinders the extraction rates. In addition, we found that dual-frequency ultrasonic transducer reactors effectively enhance extraction rates. The discussion covers additional parameters related to process intensification, such as the type of ultrasound device, vessel position, characteristics of the transmitting liquid, irradiation mode, and the ultrasound probe’s horn immersion depth. In addition, we survey future research directions for worthwhile applications that lay a theoretical foundation for further study in this area.

Zeolitic Imidazolate Framework-8 (ZIF-8) material was prepared by chemical precipitation method. The microstructure and physical properties of the as-prepared samples were characterized by XRD, BET, FESEM and UV spectrophotometer. The self-made four-channel measurement device was used to test the gas sensitivity of ZIF-8 material toward ethanol gas under photo-thermal synergistic excitation. The results showed that the sample was typical ZIF-8 (Eg = 4.96 eV) with a regular dodecahedron shape and the specific surface is up to 1793 m2/g. The as-prepared ZIF-8 has a gas response value of 55.04 to 100 ppm ethanol at 75 °C and it shows good gas sensing selectivity and repeated stability. The excellent gas sensitivity can be attributed to the increase of free electron concentration in the ZIF-8 conduction band by photo-thermal synergistic excitation, and the large specific surface area of ZIF-8 material provides more active sites for gas-solid surface reaction. The reaction mechanism of ZIF-8 material under multi-field excitation was also discussed.

This work reported the successful preparation of the CuO and SnO2 by the facile co-precipitation method for energy storage applications, especially for supercapacitors (SCs). Subsequently, a CuO-SnO2 composite was further prepared to enhance the composites electrochemical properties. The detailed research survey showed that the combination of these two typical pseudocapacitive metal oxides reasonably enhances their structural integrity, and electronic conductivity, resulting in an optimized electrochemical property. According to the electrochemical studies, an exceptional 246 C/g capacitance is revealed by the CuO-SnO2 composite than 162 C/g (SnO2) and 89 C/g (CuO) exhibiting a synergistic effect in the composite between Sn and Cu-based oxides. A high specific energy of 35.3 Wh/kg with a maximal specific power of 4000 W/kg was obtained by assembling a hybrid asymmetric SC (HASC) with activated carbon (AC), symbolized as CuO-SnO2||AC, that yields a high voltage of 1.6 V. Nevertheless, 88.7% retention in capacitance was revealed after 5000 cycles taken at a the discharge current of 15 A/g, proving the great durability of the CuO-SnO2||AC HASC. From all these exciting findings, SnO2 composite with CuO can be a potential and a viable choice for SCs and other energy storage gadgets.

Hierarchical nanostructures with appropriate morphology and surface functionalities are highly desired to achieve an optimized electrochemical property for active electrode materials. This work renders the facile hydrothermal synthesis of CdO, SnO2, and CdO-SnO2 nanocomposite, and their capacitive performance was tested. The formation of the pure samples and their composite was committed by low-temperature Raman spectroscopy and x-ray diffraction studies which revealed the tetragonal and cubic structures of CdO and SnO2 powder samples with good crystallinity and purity. The morphological postmortem reveals the formation of nanoparticles morphology of CdO with a highly smooth surface appearance. Besides, the SnO2 illustrates the morphology of the micro flowers composed of ultrathin nanosheets. More specifically, the electrochemical properties indicate the pseudocapacitive charge storage mechanism based on cyclic voltammetry and chronopotentiometry analysis. The CdO-SnO2 composite electrode displayed a higher capacitance due to additional pores/space offered for active sites and continuously allowed electrolyte ions to interact with the inner/outer surface of the electrode. These exciting findings led us to design and fabricate battery hybrid supercapacitors (BHSC) from CdO-SnO2, and activated carbon (AC), referred to as CdO-SnO2//AC BHSC, attains a high power delivery (5717 W/kg), and a maximum energy density of 42 Wh/kg at low discharge rate. Noteworthy, a stable cycling performance was obtained with only 91.3% retention after 8000 cycling at a large discharge current of 10 A/g, denoting the magnificent durability of the active electrode material.

Energy storage materials, particularly chalcogenides, are fascinating electrode materials for supercapacitors (SCs) because of their high capacitance, remarkable electrical conductivity, and multiple oxidation states contributed by numerous metal cations. Herein, a novel nanocomposite based on zinc sulfide and copper dis-elenide, denoted as (ZnS-CuSe2), was prepared via a sonochemical-assisted method. The structural analysis revealed the cubic structure for pure ZnS, orthorhombic for CuSe2, and co-existing cubic and orthorhombic phases for ZnS-CuSe2 nanocomposites with high purity and crystallinity. The ZnS-CuSe2 nanocomposite offered exceptional electrochemical performance with redox peaks from the CV analysis, and coupled with plateaus in the charge/discharge profile, confirming the faradaic energy storage properties with functional reversibility. Similarly, a high conductive feature of the ZnS-CuSe2 composite was revealed by impedance study, with a minor charge transfer resistance than their bulk materials. A hybrid asymmetric supercapacitor (HASCs) composed of ZnS-CuSe2//AC was constructed, which manifested an enlarged voltage window up to 1.7 V with capacitance of 95 F g-1 and a maximum specific energy of 38 Wh kg -1. Also, high power delivery was attained at 3927 Wkg-1 when specific energy goes down to 12 Wh kg- at 5 A g-1. Interestingly, only 81.8% retention was left beneath when cycled to 8000 cycles, specifying decent stability of the ZnS-CuSe2//AC HASCs.

The porous diamond film was fabricated via a self-developed microwave plasma chemical vapor deposition (MPCVD) system in H2/Ar plasma by utilizing micrometer-sized diamond films coated with nickel as starting material. SEM and Raman spectroscopy were used to evaluate the evolution of the morphology and sp3 phase of porous diamond with changes in the surface treatment process parameters, including the etching temperature and time. The results indicate that once the etching temperature exceeds 700 °C, the pitting etching phenomenon can be observed on the surface of diamond film. In a certain range, increasing the etching time increases the depth of surface holes on diamond film, whereas the microporous density exhibits an inverted parabolic change pattern. The porous diamond films with uniform pores structure can be obtained by adopting optimal etching process parameter when the H2/Ar plasma temperature is determined at 900 °C for 30 min. The porous formation mechanism of diamond film is attributed to the nickel particles’ heterogeneous catalysis behavior, which promotes the transition route from diamond phase to graphite phase, followed by the preferential etching of graphite phase by H2/Ar plasma.

Electrode material with exceptional durability, energy density, and rate performance has been of great interest in next-generation advanced supercapacitor applications in recent years. In this paper, we portray the facile synthesis of carbon nanofibers (CNFs) and cadmium sulfide (CdS) for a supercapacitor that obtained the capacitances of 335 F/g and 210 F/g when tested in an aqueous conducting medium in a three-electrode mode over a wide potential range between 0.0 to 0.8 V. The performance of pure electrode materials is not satisfactory; therefore, a composite of CdS/CNFs was further fabricated that exhibits enhanced energy storage performance in terms of the capacitance of 510 F/g, and a minor charge transfer resistance compared with pure counterparts. The fascinating performance was turned to develop an asymmetric supercapacitor (CdS/CNFs||AC), which realizes a high voltage of up to 2.0 V. It is believed that optimization of voltage put significant enhancement in energy and power delivery. Interestingly, a high power of 9000 W/kg was accomplished with maximum energy of 31.94 Wh/kg at high and low discharge current rates. Additionally, only a 15.3% capacity fade was attained and 85.7% retention at a high current rate of 20 A/g for 7500 cycles. Our strategy is synthesizing other metal oxide-based composite electrodes for future energy storage domains.

A promising MnO2-FeSe2 nanohybrid is reported for the first time by the wet-chemical assisted route and directly utilized as a synergistic electrode for supercapattery applications. The optimized electrochemical performance of the MnO2-FeSe2 nanohybrid is realized when tested for capacitive signature and active redox reactions. Testing for capacitive signature and active redox reactions reveals the MnO2-FeSe2 nanohybrid's enhanced electrochemical performance. The MnO2-FeSe2 nanohybrid has a greater capacitance due to the cyclic voltammetry's bigger enclosed loop area, higher current response, and longer discharge time frame. Also, due to the synergistic impact between the two pseudocapacitive materials in the three-mode assembly, the least resistance in the impedance plot was attained when compared with MnO2 and FeSe2 electrodes. Based on these striking results, MnO2-FeSe2||AC||KOH supercapattery displayed a highly stable performance (95.3% retention) at the highest current response when run for 10,000 repeated discharge-charge cycles. It achieved a high energy of 55.39 Wh/kg at the power delivery of 4320 W/kg by expanding the upper voltage cutoff to 1.7 V in an aqueous medium. Our research paves a new way to develop metal selenide nanohybrid electrodes with conventional pseudocapacitive materials that could efficiently boost the electrochemical properties of the parent materials owing to the synergistic effect. The acquired results displayed the potential growth of MnO2 and FeSe2 nanohybrid as the future active materials for sustainable and clean energy storage devices.

In this work, we fabricated metal-diamond composite material with excellent mechanical properties via pressure-less microwave sintering by using pre-alloyed metallic powder as the raw materials. The elementary substance metallic powder formula was simultaneously sintered as a comparative test. A scanning electron microscope (SEM) was used to analyze the microstructural morphology information of samples. Phase transitions were studied by an X-ray diffraction (XRD) technique. The hardness, bending strength and relative density of samples were tested to evaluate their mechanical properties. Raman spectroscopy was used to investigate the diamond graphitization. The results show that the formula of pre-alloyed metallic powder exhibited better heating efficiency under the microwave irradiation; in turn, the samples can reach targeted sintering temperature ahead of the elementary substance metallic powder samples. Furthermore, the samples sintered via pre-alloyed powders display excellent mechanical properties; the relative density, hardness and bending strength can reach 98.8%, 101.5 HRB and 1065.9 MPa, respectively. This promotional behavior can be attributed to the pre-alloyed characteristic of raw powders that facilitates the uniform distribution of metal elements and a more thorough alloying reaction even if the sintering temperature is below 900 °C. It is demonstrated that the pressure-less microwave sintering will be feasible in the fabrication of metallic matrix diamond super-hard tool bits by utilizing the pre-alloyed powders as the raw material. The combination of microwave sintering and pre-alloyed powder is expected to provide a new strategy with efficient and low cost for the preparation of super-hard material products.

Super-hard diamond drill bits were prepared with microwave hot press sintering (MHPS) method at low sintering temperature. The micro-structures were analyzed using SEM. The samples were characterized for their properties such as bending strength, hardness, relative density and compression and tensile test. The purity of the diamond in samples was investigated by Raman spectroscopy. The results display that when MHPS method is applied to the manufacture of diamond drill bits, it has prominent advantages such as shorter sintering time, lower sintering temperature et al. And the samples prepared with MHPS at 860 degrees C show excellent performance. The values of hardness, relative density and bending strength are 106.6 HRB, 97.6% and 895.8 MPa respectively. Thus, a reaction kinetic study was performed to analyze reaction mechanism. And a potential sintering mechanism of MHPS is discussed. This work will provide a theoretical basis for the preparation of diamond tools through MHPS process. (C) 2019 Elsevier B.V. All rights reserved.

Solvent extraction of samarium (III) from hydrochloric acid solution using a T-junction microreactor, with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (EHEHPA or P507) as the extractant has been investigated. Initially, the effect of aqueous pH, channel width, and channel length on the extraction of samarium was analyzed, and the maximum extraction efficiency (82.5%) was obtained under the optimal conditions: pH of 2.0, width of 1.6 mm and length of 1m. Moreover, the slug flow was analyzed by using the photo imaging system, which shows that slug length tends to slightly increase with the increase of aqueous acidity and channel width. However, the channel length did not show significant effect on the slug length. Volumetric mass transfer coefficient (kLa) initially increases with the increasing of pH value but decreases after the pH surpasses 2.0. Increasing the flow rate shows a positive effect in promoting volumetric mass transfer coefficient while enhancing the channel width and length shows negative effect. The maximum mass transfer coefficient (0.05527 s−1) can be obtained with the residence time of 14.84 s, which is almost at the inlet of the channel. The study on the mass transfer behavior of samarium extraction in the T-junction can provide reference values for other researchers.