Transition-metal hydroxides (TMHOs) show promise as pseudocapacitive materials for high-energy-density supercapacitors (SCs). However, their intrinsic conductivity is low, and significant volume expansion poses challenges, negatively impacting their electrochemical properties. In the presented study, we have innovatively engineered a CoMn-Layered Double Hydroxide (CM-LDH) composite electrode for SCs. The CM-LDH electrode showcased impressive electrochemical properties, with an exceptional specific capacitance of 10955.5 mF cm(-2) at 1.0 mA cm(-2) and maintained 1231.2 mF cm(-2) at 150.0 mA cm(-2). It exhibits robust cycling stability, retaining 83.5 % of its capacitance after 7000 cycles at 35 mA cm(-2). These values surpass the performance of most CMLDH-based materials reported in prior studies. The hybrid CM-LDH//AC device revealed a remarkable energy density of 0.409 mWh cm(-2) at 0.798 mW cm(-2), thanks to the broad potential window of 1.6 V. Additionally, the electrode demonstrated excellent longevity, maintaining 85.2 % of its actual value after 20,000 charge-discharge cycles at 25 mA cm(-2), while achieving nearly perfect Coulombic efficiency of about 100 %. This research underscores the potential of CM-LDH nanostructured electrodes as a promising candidate for advanced energy storage technologies.

In this work, an electrochemical non-enzymatic glucose sensor consisting of di-methanethiol-grafted poly (3,4propylenedioxythiophene), gold nanoparticles (Au NPs), and reduced graphene oxide (rGO) was synthesized by a one-step method through Au-S chemisorption. The structure and morphology of the as-prepared poly (ProDOT(MeSH)2)/Au/rGO composite were characterized by fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of the composite was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on glassy carbon electrode (GCE). The results show that because of the hydrogen bond interaction between the thiol group on the polymer units and the functional groups on GO, poly (ProDOT-(MeSH)2)/Au/rGO was successfully prepared. In addition, due to the unique morphological structure of the composite and the ability to absorb glucose molecules through hydrogen bonds, the poly(ProDOT-(MeSH)2)/Au/rGO electrode possesses excellent selectivity and unique sensitivity (46.13 mu A mM- 1 cm- 2) for sensing glucose in the linear range of 0.04-16.0 mM with a detection limit of (S/N = 3) 0.01. This paper demonstrates that the poly(ProDOT-(MeSH)2)/Au/rGO composite holds great promise for application as a new glucose sensor in life science.

In this study, we successfully utilized nickel foam (NF) as a scaffold for the direct deposition of ultra-thin CoMn(2)O4 (CMOs) through a one-step electrochemical deposition method. This was followed by annealing to produce a stable, free-standing electrode. This electrode was then used to develop an aqueous asymmetric supercapacitor (AASC). The optimized electrode demonstrated an exceptionally high specific capacitance of 2218.32 F g(-1) at 1 A g(-1) and excellent cyclic stability, retaining 86.67 % of its capacitance after 6000 cycles. An AASC device was also constructed, employing CMOs on NF as the cathode and commercially available activated carbon (AC) on carbon cloth (CC) as the anode. This configuration achieved a high energy density of 83.85 Wh kg(-1) at a power density of 800.03 W kg(-1), with robust cycling stability (similar to 87.16 % retention after 16,000 cycles at 30.0 A g(-1)) and nearly 100 % Coulombic efficiency. These results surpass those of many state-of-the-art supercapacitors (SCs), highlighting the significant potential for practical applications.

In this work, the NiMn2S4 nanomaterials were prepared by a two-step hydrothermal method with an external morphology similar to that of a sea hedgehog, with an overall micro-spherical shape surrounded by nanosheets (NSs). This unique nanostructure helps enhance the electrode material's specific surface area (SSA) and achieve a better pore size distribution, facilitating complete interaction among the electrolyte and the active materials. Moreover, it promotes the quick flow of electrons and smooth transport of ions, thus improving NiMn2S4 electrode electrochemical performance. The NiMn2S4 electrode achieved an capacitance of 1426.2 mF cm−2 at 1 mA cm−2, with good rate performance (∼896.6 mF cm−2 at 10 mA cm−2) and cycle stability (∼83.8 % retention after 6000 cycles). Sweep voltammetry analysis of its electrochemical behavior reveals that the primary energy storage mechanism is the capacitive contribution based on surface diffusion. This finding lays a foundation for future work on regulating and optimizing the electrochemical properties.

In order to achieve high-performance and long-lifespan supercapacitors, highly electrochemically active mate-rials and rational structural design of are highly desirable. Herein, a hierarchical electrode structure of nickel (Ni)-manganese (Mn) layered double hydroxide (NiMn-LDH)-supported manganese dioxide (MnO2), i.e., NiMn-LDH@MnO2, assembled by NiMn-LDH nanoparticles and MnO2 nanosheets was developed on nickel foam by facile electrodeposition and the subsequent hydrothermal reaction. The optimized NiMn-LDH@MnO2 electrode shows a high capacitance (-4336.8 F g-1 at 1.0 A g-1), good rate performance (-860 F g-1 at 60 A g-1) and long cycle stability (-83.2 % initial capacitance retention after 10,000 cycles at 20 A g-1). Furthermore, the aqueous asymmetric supercapacitors using the optimized NiMn-LDH@MnO2 cathode and activated carbon anode demonstrate a desirable energy density of-104.51 W h kg-1 at 800.00 W kg-1, and good cycle stability with 86.8 % initial capacitance retention and about 100 % Coulomb efficiency after 22,000 cycles at 5.0 A g-1. The above results indicate that this study offers a meaningful exploration for manufacturing the energy storage devices with high comprehensive performance.

Supercapacitors display promising electrochemical performance with high power density and excellent cycle stability. However, their low energy density limits their advancement in a broader range of applications. To enhance their energy density, we proposed self-assembled spinel NiMn2S4 nanoflakes grown on nickel foam which we successfully prepared by a facile hydrothermal method. The NiMn2S4 electrode delivers a high capacitance of 2096.7 F g−1 at 1.0 A g−1, with an exceptional rate capability ( 720.6 F g−1 at a very high current density of 100 A g−1) and good cycle stability ( 85.1

Herein, a flexible free-standing cathode of nickel (Ni)-manganese (Mn) oxide (NMO) with a cracked-bark shape composited with aggregated nanoparticles on carbon cloth by simple one-step electrodeposition and the following annealing is reported. Benefiting from the high specific surface area because of the open structure and meanwhile from the effective stress relief due to the cracked-bark shape, a capacitance of up to 6768.7 mF cm(-2) (1.0 mA cm(-2)), good rate performance (similar to 1416.8 mF cm(-2) at 60.0 mA cm(-2)), and cycle stability are delivered by the optimized NMO cathode. An aqueous asymmetric supercapacitor assembled with the NMO cathode and commercial activated carbon anode has an energy density of 0.492 mWh cm(-2) at 0.800 mW cm(-2) and good capacitance retention of similar to 82.3% after 15000 cycles at 20.0 mA cm(-2) with similar to 100% Columbic efficiency. In view of the excellent performance, high elemental abundance, eco-friendliness, and facile preparation, we believe that this study offers a useful attempt to construct high-performance aqueous AASCs.

Herein, a flexible cathode with high performance, which consists of nickel (Ni)-manganese (Mn) sulfide (5) microparticles on activated carbon cloth (ACC), i.e., Ni-Mn-S/ACC, prepared by one-step electrodeposition of the Ni-Mn based compound and subsequent sulfurization is reported. The optimized Ni-Mn-S/ACC cathode has a high capacitance (similar to 12789.6 mF cm(-2) at 1.0 mA cm(-2)), good rate performance (similar to 3352 mF cm(-2) up to 60.0 mA cm(-2)) and cycling behavior (similar to 81.7% retention of the initial capacitance after 5000 cycles at 50 mA cm(-2)). An aqueous asymmetric supercapacitor assembled using the cathode of Ni-Mn-S/ACC, the anode of activated carbon on carbon cloth and the electrolyte of 6.0 M potassium hydroxide delivers a desirable energy density of similar to 0.789 mWh cm(-2) at 0.850 mW cm(-2) and good cycling performance of similar to 82.8% capacitance retention after 18,000 cycles at 25.0 mA cm(-2) with the Coulombic efficiency around 100%.

In this work, we report a high-performance and self-standing supercapacitor electrode composed of a Co and Mn layered double hydroxide (CoMn-LDH) nanostructure on Ni foam (NF) prepared by one-step electrochemical deposition. The CoMn-LDH electrode delivers a high capacitance of-2673.6 F g(-1) at 1 A g(-1), with the excellent rate performance (-1488.0 F g(-1) at 60 A g(-1)) and good cycle stability (-86.7% capacitance retention after 5000 cycles at 12 A g(-1)). The asymmetric supercapacitors assembled using the cathode of CoMn-LDH, the anode of activated carbon on carbon cloth and the electrolyte of 2.0 M KOH yield an energy density of-97.5 W h kg(-1) at 800.0 W kg(-1), good cycling performance of-89.2% capacitance retention after 5000 cycles at 5 A g(-1) with the Columbic efficiency around 100%. These results indicate that the CoMn-LDH nanostructure on NF is a promising electrode for high-performance energy storage applications.

In this work, we report a high-performance self-standing electrode of Mn(OH)(2)-coated Ni3S2 (Ni3S2@Mn(OH)(2)) nanosheets on Ni foam by hydrothermally growing the Ni3S2 nanosheets and electrodepositing Mn(OH)(2) around Ni3S2. The structure of the Ni3S2 nanosheets grown by the hydrothermal method is more stable, and the electrodeposition method is easier to synthesize Mn(OH)(2) without using any binder. The electrochemical characterization demonstrates that combining the Ni3S2 nanosheet with the Mn(OH)(2) coating is an effective way to improving the charge storage performance because of the synergetic effects of both materials/structures. The electrode possesses a high area-specific capacitance of 6430.2 mF cm(-2) at 1 mA cm(-2) and good cycle stability with similar to 80.9% capacitance retention after 9000 cycles at 8 mA cm(-2). The aqueous asymmetric supercapacitors assembled with the Ni3S2@Mn(OH)(2) cathode, the activated carbon anode and 1 M KOH electrolyte delivers an energy density of 0.371 mWh cm(-2) at 0.799 mW cm(-2), as well as good cycle stability with similar to 86.3% capacity retention after 10,000 cycles at 20 mA cm(-2). Given the high performance and relatively simple preparation, this work provides a valuable exploration of developing high-performance cathodes for aqueous supercapacitors.

In this study, we have carried out the Raman scattering measurement on the pure ferroelastic Pb-3(PO4)(2) single crystal at the temperature from the room temperature up to 300 degrees C . The lowest-frequency mode at 41 cm(-1) at ambient temperature observed in vertical polarization/perpendicular-polarized (VH) scattering geometry shows slight softening up to the ferroelastic Curie temperature, T-c = 182 degrees C , and disappeared above this temperature, while in parallel polarization (VV) geometry, this lowest mode did not fully disappear above 182 degrees C . The modes at 140 cm(-1), 159 cm(-1), and 184 cm(-1) are merged into one broad peak above 182 degrees C .

In this work, we report a high-performance self-standing supercapacitor electrode of mixed nickel manganese sulfides (NMSs) with a cracked-bark shape grown by one-step electrochemical deposition on activated carbon cloth (ACC). The electrode possesses outstanding electrochemical properties, including a high specific capacitance of up to 3142.8 F g−1 at 1.0 A g−1, the high-rate performance (∼ 1206.8 F g−1 at 60.0 A g−1), and cycle stability (∼ 92.3% capacitance retention after 8000 cycles at 8 A g−1). An asymmetric supercapacitor assembled using NMSs on ACC as the cathode, activated carbon on carbon cloth as the anode and 1.0 mol L−1 KOH as the electrolyte delivers a high energy density of 111.2 W h kg−1 at 800.0 W kg−1 and the prominent cycling performance of ∼ 93.2% capacitance retention after 10000 cycles at 5 A g−1 with the Columbic efficiency of around 100% during these 10000 cycles. The high performance and facile preparation indicate that the NMSs on ACC hold a huge potential as the electrode for supercapacitors.

After more than 40 years of development, surface-enhanced Raman spectroscopy (SERS) has become a powerful and mature analytical tool. It has been widely used in surface science, materials science, biomedicine, drug analysis, food safety, environmental testing, etc. SERS technology has molecular-level detection accuracy, which can effectively amplify signals and has obvious advantages in realizing trace substance detection. In present article, a comprehensive review of the SERS technology and related applications in microbial identification is carried out, and its future research hotspots and development directions are discussed.

Aqueous zinc (Zn)-ion batteries (AZIBs) are one of the most promising secondary battery technologies for electricity storage with high performance-to-cost ratios. Herein, a highly reversible AZIB using interconnected vertical δ-MnO2 nanoflakes coated by a dopamine-derived carbon thin shell of ∼2 nm in thickness on carbon cloth as a self-supporting cathode is reported. The vertical nanoflake structure ensures the effective contact with electrolyte, large specific surface area and efficient stress relief during charge and discharge processes, and the coated thin carbon shell increases the electrical conductivity of the cathode and meanwhile relieves the dissolution of the electrode material during cycle. Thanks to these advantages, a high capacity of ∼346.7 mA h g–1 at 0.5 A g–1 and good long-term cycling stability with 96.8% capacity retention after 2000 cycles at 6.0 A g–1 can be delivered. Furthermore, the electricity storage mechanism is investigated using various characterization tools. Benefiting from the facile preparation and high performance, this study is believed to provide a valuable exploration of high-performance self-supporting cathodes for aqueous Zn-ion batteries.

In this paper, we report a self-supported flexible electrode consisting of NiCoMnS4 nanosheets on NiCo2O4 nanowires, denoted as NiCo2O4@NiCoMnS4 (NCO@NCMS) prepared by the hydrothermal growth (NiCo2O4) and the following electrodeposition (NiCoMnS4) on a carbon cloth (CC) substrate. The electrode delivers a high specific capacity of 4836 mF cm(-2) at 1 mA cm(-2) and excellent rate performance, i.e., 3820 mF cm(-2) at 10 mA cm(-2) and 2820 mF cm(-2) even at 60 mA cm(-2). An aqueous asymmetric supercapacitor (AASC) assembled using NCO@NCMS on CC as the cathode, activated carbon on CC as the anode and 2 M KOH as the electrolyte delivers a high energy density of 0.399 mWh cm(-2) at 0.85 mW cm(-2) and excellent cycle stability with similar to 81.2% capacity retention after 20 0 0 0 cycles at a high current density of 20 mA cm(-2). In view of the excellent performance and facile preparation, this study is believed to provide a valuable exploration of developing high-performance electrodes and AASCs. (C) 2021 Elsevier Ltd. All rights reserved.

The metal catalyst has good electrical conductivity, is simple to prepare and easy to be applied in practice. It is currently the most in-depth researched catalyst for electrochemical reduction of carbon dioxide. In recent decades, metals such as copper, cobalt, tin, and gold have been used as electrode catalysts for reducing carbon dioxide. From the perspective of the reduction mechanism of carbon dioxide, it is generally believed that the formation of C intermediate is the rate-determining step of the entire reduction reaction. One of the main functions of metal catalysts is to enable the corresponding reaction intermediates to exist stably, thereby improving the energy efficiency of the reaction. According to the combination with different intermediates and the different products obtained, the metal electrode catalysts can be divided into three categories. In this paper, the current research status of electrocatalytic and photocatalytic reduction of carbon dioxide and carbon dioxide under Raman spectroscopy are introduced. Also elaborate, the Raman spectroscopic characterization of carbon dioxide has been introduced in this paper with emphasis on the changes of Fermi resonance peaks of CO2 with temperature and pressure. The advantages and disadvantages of using metal and metal complexes, carbon materials, composite materials and MOF materials to reduce CO2 are introduced. The method was improved, and finally focused on the core issues of improving reactivity and product selectivity, and analyzed the shortcomings of current electrocatalytic processes extended to large-scale production applications from surface engineering, chemical modification, nano or composite materials. There are other ways to improve the activity of the catalyst from these aspects, as well as the prospects for future research.

The potential window for aqueous supercapacitor cathodes greatly depends on the electrochemical stability of water, and thus is generally limited to similar to 1.2 V. Herein, a 1.4 V potential window (vs Ag/AgCl) in the 5 M NaNO3 aqueous electrolyte for porous delta-MnO2 with a hierarchical interconnected nanosheet structure grown on electrochemically roughened graphite paper by electrodeposition is reported. A specific capacitance of similar to 407.6 F g(-1) is delivered at 1 A g(-1), and capacitance retention up to similar to 90.7% is achieved after 5000 cycles at 8 A g(-1). The aqueous asymmetric supercapacitors of 2.4 V are assembled with the configuration of delta-MnO2//activated carbon, and an energy density (E) of similar to 38.4 Wh kg(-1) is obtained at 599.7 W kg(-1) (even at 12 kW kg(-1), E of similar to 21.7 Wh kg(-1) is still delivered). Moreover, the asymmetric supercapacitors exhibit good rate and cycling performance. Thanks to the simple preparation for the electrode materials/structures and high device performance, it is believed that this work provides valuable contributions to developing aqueous supercapacitors delivering a broad working voltage window and thus an elevated energy density.

Methanol and ethanol are the simplest alcohols, which are widely used in industrial and medical fields, and even in daily life, we are often exposed to them because the basic component of various wines is ethanol, but the so-called “fake wine” is often accompanied by some methanol components. Here, in order to establish a method for measuring the concentration of methanol using Raman spectroscopy, the laser Raman method was used to study Raman spectroscopy of methanol and ethanol liquid samples. The research results show that due to the difference in the chemical structure, the Raman spectra of ethanol and methanol have significantly different characteristics. This study indicates that the 2840.2 cm−1 Raman shift is the main spectral basis for the detection of methanol; for ethanol, 888 cm−1, 1054.7 cm−1, and 1287.3 cm−1 are the most characteristic ones, and the identification of methanol in various liquid phases has certain practical value.

For aqueous supercapacitors, the working voltage is normally limited below 2 V because of the electrochemical stability of water, which limits improvement of the energy density and thus severely hinders their practical application. I lerem, a flexible electrode of interconnected delta-MnO2 nanosheets anchored on activated carbon cloth with a potential window (vs Ag/AgCl) extending to 1.2 V is developed using simple one-step water bath only at 40 degrees C. A high specific capacitance up to 360.5 F g(-1) at 1 A g(-1) combining with good rate performance and electrochemical stability is delivered. Folding test indicates that the charge storage performance of the electrode has neglected degradation during the 2000 times of folding. Furthermore, a 2.4 V aqueous asymmetric supercapacitor is assembled based on the device configuration of activated carbon//delta-MnO2 and a high energy density of 49.8 Wh kg(-1) at the power density of 1198.4 W kg(-1) and good electrochemical stability, i.e., 90.6%capacitance retention after 5000 cycles can be achieved. Thanks to the good energy storage performance, high flexibility and simple preparation of the material, it is believed that this work provides a valuable exploration to develop high-performance flexible aqueous asymmetric energy storage devices.