Hollow Electrode Research Articles

Engineering interfacial molecular interactions on Ag Hollow fibre gas diffusion electrodes for high efficiency in CO2 conversion to CO.

The electrochemical CO2 reduction reaction (CO2RR) occurs at the nanoscale interface of the electrode-electrolyte. Therefore, tailoring the interfacial properties in the interface microenvironment provides a powerful strategy to optimise the activity and selectivity of electrocatalysts towards the desired products. Here, the microenvironment at the electrode-electrolyte interface of the flow-through Ag-based hollow fibre gas diffusion electrode (Ag HFGDE) is modulated by introducing surfactant cetyltrimethylammonium bromide (CTAB) as the electrolyte additive. The porous hollow fibre configuration and gas penetration mode facilitate the CO2 mass transfer and the formation of the triple-phase interface. Through the ordered arrangement of hydrophobic long-alkyl chains, CTAB molecules at the electrode/electrolyte interface promoted CO2 penetration to active sites and repelled water to reduce the activity of competitive hydrogen evolution reaction (HER). By applying CTAB-containing catholyte, Ag HFGDE achieved a high CO Faradaic efficiency (FE) of over 95 % in a wide potential range and double the partial current density of CO. The enhancement of CO selectivity and suppression of hydrogen was attributed to the improvement of charge transfer and the CO2/H2O ratio enhancement. These findings highlight the importance of adjusting the local microenvironment to enhance the reaction kinetics and product selectivity in the electrochemical CO2 reduction reaction CO2RR.

Phase change-mediated core-sheath 3D printing of hollow microlattice pseudocapacitive aerogel electrode with favorable electrochemical properties

Channel-interconnected regulation within 3D-printed pseudocapacitive electrode architecture to generate high active material loading/utilization and fast ion transport is pivotal but challenging for implementing high-performance pseudocapacitance system. Herein, we demonstrated an innovative phase change-mediated core-sheath direct ink writing (DIW) 3D printing strategy for controllably constructing pseudocapacitive hollow-microlattice graphene/NiCo2O4 aerogel (HGNA) electrode, with regular hollow channels in printed filaments and abundant well-interconnected hierarchical pores built by jointing tortuous pseudocapacitive graphene nanosheets. The unique architectural features facilitated highly efficient diffusion and infiltration of substance throughout the entire thick filaments from both “interior-exterior” and “exterior-interior” directions, thereby enabling high-level yet effective loading of active materials as well as unimpeded ion transport across the printed bulk-structured electrode. Kinetics analysis revealed that the capacitance of pseudocapacitive HGNA electrode was primarily contributed from fast kinetic process. An asymmetric device assembled with DIW-printed HGNA electrode boasted a high energy storage performance with capacitance of 3.43 F cm−2 and energy density of 1.01 mWh cm−2, while featuring remarkable cycling stability (87% after 8000 cycles) and superior capacity even at large electrode thickness. This work opens a promising route for processing rational pseudocapacitive electrode architectures toward high-capacity, fast-kinetics devices.

Reducing equivalent magnetic noise by electrode design and magnetic annealing in Quartz/Metglas magnetoelectric sensors

Magnetoelectric (ME) composites are promising for the development of high-performance magnetometers due to their high sensitivity, low cost, low power consumption, and small size. Enhancing the ME coefficient while reducing the background noise is an effective method to improve the performance of ME sensors, which remains challenging. In this work, we propose a method to reduce the equivalent magnetic noise by optimizing the electrode design and the magnetic annealing process in magnetoelectric quartz/Metglas composites. Compared with the non-optimized ME composites, the ME coefficient increases by 1.38 times while the background noise decreases by about 0.78 times, resulting in a LoD of 10 fT at resonance. Due to the high ME coefficient and low background noise, the equivalent magnetic noise from 20 kHz to 50 kHz was less than 6.10 pT/Hz1/2. The results show that proper annealing treatment of Metglas is beneficial for improving the soft magnetic properties. Meanwhile, the hollow electrode of quartz can reduce the equivalent capacitance and enhance the quality factor of the piezoelectric layer. This work demonstrates a feasible way to enhance the performance of ME magnetic field sensors.

A Dual-Carbon Potassium-Ion Capacitor Enabled by Hollow Carbon Fibrous Electrodes with Reduced Graphitization.

The large size of K+ ions (1.38 Å) sets a challenge in achieving high kinetics and long lifespan of potassium storage devices. Here, a fibrous ZrO2 membrane is utilized as a reactive template to construct a dual-carbon K-ion capacitor. Unlike graphite, ZrO2-catalyzed graphitic carbon presents a relatively disordered layer arrangement with an expanded interlayer spacing of 0.378nm to accommodate K+ insertion/extraction. Pyridine-derived nitrogen sites can locally store K-ions without disrupting the formation of stage-1 graphite intercalation compounds (GICs). Consequently, N-doped hollow graphitic carbon fiber achieves a K+-storage capacity (primarily below 1V), which is 1.5 time that of commercial graphite. Potassium-ion hybrid capacitors are assembled using the hollow carbon fiber electrodes and the ZrO2 nanofiber membrane as the separator. The capacitor exhibits a high power of 40 000 W kg-1, full charge in 8.5 s, 93% capacity retention after 5000 cycles at 2 A g-1, and a low self-discharge rate of 8.6mV h-1. The scalability and high performance of the lattice-expanded tubular carbon electrodes underscores may advance the practical potassium-ion capacitors.

Electrochemical-mechanical coupled lithium growth in fiber-structured electrodes

Lithium plating (stripping) on the electrode surface and embedding inside the electrode occur simultaneously in lithium-ion batteries during fast (dis)charging, which involves both deposition and diffusion mechanisms. The paper presents a developed finite-element procedure that accommodates these two mechanisms, facilitating the modeling of the (dis)charging process in electrodes. The framework, which integrates interface electrochemical reaction kinetics, electrochemical-mechanical coupling, comprehensive constitutive models for silicon/graphite/lithium, and a surface growth re-meshing algorithm, is capable of real-time simulation of the surface deposition and coupled diffusion-deformation processes on the electrode substrate. We examined the effects of charging rate, diffusion rate and volumetric expansion on the stress of the plated lithium layer in a fiber-structured electrode. By accounting for creep in lithium metal and subsequent stress relaxation, we obtained time-dependent stress profiles in the plated lithium layer. As an application, we quantified electroplating stresses in both fiber-structured graphite and silicon electrodes. Taking the silicon electrode as a model case, we demonstrate that hollow fiber structural electrodes can also alleviate the stress in the surface lithium-plating layer. The numerical framework may be further applied to explorations for the optimization of electrode structures in advanced high performance lithium-ion batteries.

Novel hollow-electrode glow discharge mass spectrometry for the quantitative analysis of protein content in food.

Protein content in food is an important indicator of nutritional value and food safety. Therefore, it is of great significance to accurately detect protein content in food. In this work, a combustion furnace and novel hollow-electrode glow discharge ion source-quadrupole mass spectrometry (HGD-MS) were designed, which were used to construct a "combustion furnace + mass spectrometry" experimental platform to detect the protein content in food. Five food standard samples were selected for the analysis. The food samples were combusted in the combustion furnace at a high temperature (1300 °C) in an oxygen-rich environment. The gas products were passed into the novel hollow electrode glow discharge ion source-quadrupole mass spectrometer. A standard curve of y = 635.06x + 11 082, R2 = 0.9994 was plotted by detecting the NO+ ion intensity at a relative standard deviation (RSD) of 1.8% to 5.7%. Using the same method, food samples no. 6 and 7 were combusted and NO+ ion intensity was measured to verify the accuracy of the quantitation curve. Subsequently, the protein content was determined using a nitrogen-to-protein conversion factor of 6.25. This method provides a rapid, accurate, and environmentally friendly approach for determining protein content in food.

Numerical investigation of the sensible heat storage in novel electrostatic precipitators with liquid-filled collection electrodes

Heat recovery from flue gas holds significant potential for energy conservation. A strategy is proposed for recovering and storing heat in electrostatic precipitators by utilizing liquid-filled collection electrodes. In the prototype, the hollow collection electrode is connected to the heat storage tank. Convective heat transfer occurs between the gas stream and the liquid contained in the collection electrode. The heat storage mechanism is revealed by numerical simulation of corona discharge, flow and heat transfer processes in a simplified electrostatic precipitator. The results indicate that both the gas-side and liquid-side heat transfer coefficients reach steady values within approximately 100 s. The buoyancy-driven liquid flow results in a heat transfer coefficient that is 28 times higher than that for gas-side forced convection. Increasing the gas inlet temperature leads to a greater buoyancy force and, consequently, a higher heat transfer coefficient on the liquid side. Both ionic wind and inlet velocity affect the gas-side heat transfer. The ionic wind disturbs the thermal boundary layer, leading to a 27.9 % increase in the gas-side heat transfer coefficient at an inlet velocity of 0.5 m/s. Furthermore, this enhancement becomes more pronounced as the inlet velocity decreases. The flow pattern of liquid in the collection electrode and heat storage tank is crucial to the heat storage process. Additionally, installing the heat storage tank above the electrostatic precipitator provides added benefits. During the process of heat storage, the largest heat resistance is found on the gas side.

Ampere-level CO2 electroreduction with single-pass conversion exceeding 85% in acid over silver penetration electrodes

Synthesis of valuable chemicals from CO2 electroreduction in acidic media is highly desirable to overcome carbonation. However, suppressing the hydrogen evolution reaction in such proton-rich environments remains a considerable challenge. The current study demonstrates the use of a hollow fiber silver penetration electrode with hierarchical micro/nanostructures to enable CO2 reduction to CO in strong acids via balanced coordination of CO2 and K+/H+ supplies. Correspondingly, a CO faradaic efficiency of 95% is achieved at a partial current density as high as 4.3 A/cm2 in a pH = 1 solution of H2SO4 and KCl, sustaining 200 h of continuous electrolysis at a current density of 2 A/cm2 with over 85% single-pass conversion of CO2. The experimental results and density functional theory calculations suggest that the controllable CO2 feeding induced by the hollow fiber penetration configuration primarily coordinate the CO2/H+ balance on Ag active sites in strong acids, favoring CO2 activation and key intermediate *COOH formation, resulting in enhanced CO formation.

Ni Single Atom Decorated Porous Hollow Carbon Nanosphere-Based Electrodes for High Performance Symmetric Solid-State Supercapacitors.

Ni single atom containing hollow carbon nanospheres with nitrogen doping has been synthesized by carbonization of Ni(NO3)2/phloroglucinol-formaldehyde polymer/silica composite. The samples have been characterized by powder X-ray diffraction, nitrogen adsorption/desorption, electron microscopic, Raman and X-ray photoelectron spectroscopic studies. The microstructure and surface area vary with the amount of Ni(NO3)2 employed in the syntheses and the carbonization environment. An optimized amount of nickel and argon as the carbonization gas afford Ni-1.0@N@HCN-Ar which possesses overall superior features. The uniformly dispersed Ni single atoms within the hollow porous carbon framework fully utilize all the electroactive sites thereby improving the supercapacitive performance. The specific capacitance of Ni-1.0@N@HCN-Ar reaches 777 F g-1 at 1 A g-1 with a Coulombic efficiency of 98.4 % and excellent recyclability. The energy and power density of Ni-1.0@N@HCN-Ar are found to be high; at 1 A g-1 its energy density is 155.4 Wh kg-1 with a power density of 600.3 W kg-1. At a high current density of 10 A g-1 the material shows a high energy density of 118.4 Wh kg-1 with excellent power density of 6003.4 W kg-1. A symmetric solid-state supercapacitor assembled with this material, Ni-1.0@N@HCN-Ar//Ni-1.0@N@HCN-Ar using H2SO4/PVA gel electrolyte shows a superior energy density value of 30 Wh kg-1 at a power density of 1200 W kg-1.

Dual-course dielectric barrier discharge with a novel hollow micro-holes electrode to efficiently mitigate NOx

The effect of a novel hollow annular micro-hole electrode on the DBD de-NOx performance was investigated. The experimental results show that the hollow electrode allows the feed gas to take full advantage of the redundant heat of the electrode, thus reducing the energy consumption of the system. Subsequently, the micro-hole structure can improve the uniformity of feed gas in the plasma channel and prolong the residence time of the feed gas in the plasma channel. The reactor can also raise the temperature of the feed gas and enhance the plasma electric field. The optimum NOx removal efficiency of about 82.6% is achieved at 16 annular micro-holes. Compared to the rod electrode reactor, the novel electrode reactor shows 19.7% reduction in energy consumption and 13.2% enhancement in de-NOx efficiency. The calculations of de-NOx mechanism show that the NO2 concentration decays significantly as the feed gas residence time increases, accompanied by a slight increase in N2O concentration. The NO2 concentration marginally increases while N2O concentration slightly decreases as the increase of feed gas temperature. DBD de-NOx presents the mode of accelerated reduction of NO, essential removal of NO2, and gradual consumption of N2O with the reduced electric field increases.

Hollow fiber gas-diffusion electrodes with tailored crystal facets for tuning syngas production in electrochemical CO2 reduction

Electrochemical reduction of CO2 (CO2RR) in aqueous electrolytes not only relies on advanced gas diffusion electrodes (GDEs) to improve CO2 mass transportation but also efficient electrocatalysts to produce specific products. Herein, to produce syngas (CO and H2 mixture), a facet-orientated zinc nanosheet catalyst was electrodeposited on the Cu hollow fiber GDE via a controllable facile surfactant-assisted method. The introduction of cationic surfactant cetyl trimethyl ammonium bromide (CTAB) could manipulate the nucleation and crystal growth of zinc ions around the GDE during the electrodeposition process, leading to controlled changes in the surface free energy and tuned zinc crystal growth orientation. Consequently, the ZncNS-HF with the largest ratio of Zn (101)/Zn (002), resulted in a high current density of 73.3 mA/cm2 and a high syngas production rate of 1328.6 µmol/h∙cm2 at applied potential −1.3 V (vs. RHE). This comes from the hierarchical structure of HFGDE, which provides sufficient CO2 reaching the catalyst/electrolyte interface, and the well-connected zinc nanosheets contribute to a significant number of active sites for CO2RR. This is the first time to configure flow-through or gas-penetrated HFGDEs with zinc crystal facets controlled nanosheet catalysts for syngas production. This research demonstrates the high potential of nanoengineering catalysts for HFGDEs to achieve high production rates of syngas.

Development of an autonomous on-site dissolved inorganic carbon analyzer using conductometric detection

BackgroundThe increase in anthropogenic CO2 concentrations in the Earth's atmosphere since the industrial revolution has resulted in an increased uptake of CO2 by the oceans, leading to ocean acidification. Dissolved Inorganic Carbon (DIC) is one of the key variables to characterize the seawater carbonate system. High quality DIC observations at a high spatial-temporal resolution is required to improve our understanding of the marine carbonate system. To meet the requirements, autonomous DIC analyzers are needed which offer a high sampling frequency, are cost-effective and have a low reagent and power consumption. ResultsWe present the development and validation of a novel analyzer for autonomous measurements of DIC in seawater using conductometric detection. The analyzer employs a gas diffusion sequential injection approach in a “Tube In A Tube” configuration that facilitates diffusion of gaseous CO2 from an acidified sample through a gas permeable membrane into a stream of an alkaline solution. The change in conductivity in the alkaline medium is proportional to the DIC concentration of the sample and is measured using a detection cell constructed of 4 hollow brass electrodes. Physical and chemical optimizations of the analyzer yielded a sampling frequency of 4 samples h−1 using sub mL reagent volumes for each measurement. Temperature and salinity effects on DIC measurements were mathematically corrected to increase accuracy. Analytical precision of ±4.9 μmol kg−1 and ±9.7 μmol kg−1 were achieved from measurements of a DIC reference material in the laboratory and during a field deployment in the southwest Baltic Sea, respectively. SignificanceThis study describes a simple, cost-effective, autonomous, on-site benchtop DIC analyzer capable of measuring DIC in seawater at a high temporal resolution as a step towards an underwater DIC sensor. The analyzer is able to measure a wide range of DIC concentrations in both fresh and marine waters. The achieved accuracy and precision offer an excellent opportunity to employ the analyzer for ocean acidification studies and CO2 leakage detection in the context of Carbon Capture and Storage operations.

Exploring tool geometry influence on EDD of Waspaloy

ABSTRACT Electric discharge drilling (EDD) is a competent method for drilling hard-to-cut materials despite its drawbacks, including minimum material removal rate (MRR), excess tool wear rate (TWR), high surface roughness (R a ), and power consumption (PC). To address these issues, EDD’s performance was explored by varying factors like tool electrode geometry (TEG), current (I), pulse-on-time (TON ), and tool electrode speed (TES) to investigate the effect on MRR, TWR, R a , and PC. Cu-6 produced the highest MRR of 36.26 mm³/min, surpassing Cu-7, Cu-8, and Cu-solid by 28.309%, 44.866%, and 51.843% respectively. Cu-solid revealed the lowest TWR of 4.397%, significantly lower than Cu-6, Cu-7, and Cu-8. R a followed the trend: Cu-solid < Cu-8 < Cu-7 < Cu-6. Cu-solid consumed more power than hollow electrodes. Microscopic analysis attributed rough surfaces to high currents. Energy dispersive X-ray (EDX) analysis exhibits material migration from a workpiece and tool electrode on the machined surface. .

Recent Progress in Hollow Fiber Gas Diffusion Electrodes for CO2 Electroreduction

CO2 electroreduction (CO2RR) to high‐value chemicals by renewable energy is a promising route for achieving carbon cycling. Traditional two‐dimensional planar electrodes applied in CO2RR are faced with problems of high mass transfer resistance, carbonate precipitation, flooding, and complicated structures, seriously limiting their CO2RR efficiency and application. Three‐dimensional hollow fiber gas diffusion electrodes (HFGDEs) are promising candidates due to their rich specific surface area, low mass transfer resistance, simplified component, and no flooding trouble, which are beneficial for achieving high current density as well as high CO2RR efficiency. In this review, we provide inspirations and positive paradigms for the rational design of HFGDE toward CO2RR by following part: 1. The mechanism of CO2RR. 2. The classification of the typical metal‐based CO2RR catalysts. 3. The preparation process of HFGDEs. 4. Recent advanced HFGDE studies for CO2RR. 5. Challenges at this stage and future development of HFGDEs towards accelerating application of industrial CO2 reduction electrolyzers.

Plasma density enhancement in radio-frequency hollow electrode discharge

The plasma density enhancement outside hollow electrodes in capacitively coupled radio-frequency (RF) discharges is investigated by a two-dimensional (2D) particle-in-cell/Monte-Carlo collision (PIC/MCC) model. Results show that plasma exists inside the cavity when the sheath inside the hollow electrode hole is fully collapsed, which is an essential condition for the plasma density enhancement outside hollow electrodes. In addition, the existence of the electron density peak at the orifice is generated via the hollow cathode effect (HCE), which plays an important role in the density enhancement. It is also found that the radial width of bulk plasma at the orifice affects the magnitude of the density enhancement, and narrow radial plasma bulk width at the orifice is not beneficial to obtain high-density plasma outside hollow electrodes. Higher electron density at the orifice, combined with larger radial plasma bulk width at the orifice, causes higher electron density outside hollow electrodes. The results also imply that the HCE strength inside the cavity cannot be determined by the magnitude of the electron density outside hollow electrodes.

Моделирование скругления острых кромок наклонных охлаждающих отверстий лопаток турбин методом электроэрозионного фрезерования на многоосевых станках с ЧПУ

The article views efficiency improving issues, quality and accuracy of sharp edge smoothing for numerous angular fans in the turbine blades of gas turbine engines made of heat-resistant nickel alloys and used in modern growing passenger aviation transport based on the development of ED milling new technology for modern multi-axis CNC machines with a rotating hollow electrode and a high-pressure fluidsupply of a special flush through the electrode body. An automated process for sharp edge machining has been developed for the production of more than 200 differently placed angular fans with a diameter of 0,45…0,6 mm in one blade instead of labor-intensive manual benchwork, where various needles, abrasive and metal rotary files are used. It is found that modeling and the development of special software resulted in a uniform radius of smoothing with high accuracy due to automatic ED milling operation along the entire trailing edge of each angular hole in the turbine blades at a multi-axis machining electro discharge center. The use of a rounded edge of the outlet ports provides more efficient cooling of the turbine blades and higher performance of gas turbine engines. At the same time, it is found that with a significant efficiency improving in blade sharp edge machining, a higher quality of the rounded edge surfaces in the holes is ensured. The results of the conducted research are recommended for the adoption of technologies in the aircraft engine industry.

A Conductive Microcavity Created by Assembly of Carbon Nanotube Buckypapers for Developing Electrochemically Wired Enzyme Cascades.

We describe the creation of a conductive microcavity based on the assembly of two pieces of carbon nanotube buckypaper for the entrapment of two enzymes, horseradish peroxidase (HRP) and glucose oxidase (GOx), as well as a redox mediator: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS). The hollow electrode, employing GOx, HRP, and the mediator, as an electrochemical enzyme cascade model, is utilized for glucose sensing at a potential of 50 mV vs. Ag/AgCl. This bienzyme electrode demonstrates the ability to oxidize glucose by GOx and subsequently convert H2O2 to water via the electrical wiring of HRP by ABTS. Different redox mediators (ABTS, potassium hexacyanoferrate (III), and hydroquinone) are tested for HRP wiring, with ABTS being the best candidate for the electroenzymatic reduction of H2O2. To demonstrate the possibility to optimize the enzyme cascade configuration, the enzyme ratio is studied with 1 mg HRP combined with variable amounts of GOx (1-4 mg) and 2 mg GOx combined with variable amounts of HRP (0.5-2 mg). The bienzyme electrode shows continuous operational stability for over a week and an excellent storage stability in phosphate buffer, with a decay of catalytic current by only 29% for 1 mM glucose after 100 days.

Evolving non-aggregated ZIF-8 nanoparticles into hierarchically porous hollow carbon nanofibers for high-performance flexible zinc-ion hybrid supercapacitor

Zinc-ion hybrid supercapacitors are garnering widespread interest in wearable energy storage devices due to their high power density, intrinsic safety and cost-effectiveness. However, the primary obstacle to their progress lies in the scarcity of cathode materials that concurrently demonstrate excellent flexibility and high energy density. Herein, we deliberately design a coaxial electrospinning ZIF-8 derived hollow carbon nanofiber film electrode (C-PAN(ZIF-8)@PVP) to achieve high-performance flexible ZHSCs. The distinctive configuration of C-PAN(ZIF-8)@PVP electrode comprises a shell of homogeneously distributed ZIF-8 derived porous carbon nanoparticles, which are bound together by N-doped carbon fibers derived from polyacrylonitrile (PAN), and a channel through the fiber created by the decomposition of polyvinylpyrrolidone (PVP). This unique architecture coupled with N, O co-doping bestows ample electrolyte infiltration, complete exposure of active sites, and a rapid pathway for electron conduction, resulting in facilitated ion diffusion kinetics, abundant active sites and enhanced electronic conductivity of the C-PAN(ZIF-8)@PVP electrode. As a result, the assembled ZHSC delivers a high reversible capacity of 116 mAh g−1 at 0.1 A g−1 and remarkable capacity retention of 100% over 4000 cycles at 5 A g−1. Moreover, it exhibits exceptional mechanical flexibility, capable of delivering stable output under arbitrary deformation. The intricate structural design strategy offers valuable insights for the development of high-performance electrode materials.

Cylindrical-electrode triboelectric nanogenerator for low-speed wind energy harvesting

In the state-of-the-art turbine-based technology, an effective wind energy harvesting is feasible only with wind speeds higher than 3 m/s. For convenient energy harvesting at lower wind speeds, a triboelectric nanogenerator (TENG) with a hollow cylindrical top electrode made of aluminum foil has been proposed in this study, which is potent to scavenge the wind energy at very low speed of 1.5 m/s. The hollow and light-weight design of the cylindrical electrode (CE) enhances the levels of air flow-induced fluttering, which aids the CE-TENG to achieve an average power density of ∼39 mW/m2 at a low wind speed of 1.5 m/s, which is remarkable among its rivals in terms of relative performance and simplicity. In addition to driving the low-power external electronics with low-speed wind energy and harvesting of low-speed natural breeze energy, CE-TENG has been also demonstrated to scavenge energy from the air-flow generated from movement of nearby traffic. This work suggests that capabilities of TENGs can be extended with unique design strategies and optimizations to attain high efficiency for wind energy harvesting in low-speed regimes.

Hollow Cuboidal Metal Oxide-Based Asymmetric Electrode Configuration for High-Performance Anion Exchange through Quaternized Pyridine-Poly(vinyl alcohol) @ Metal Hydroxide Nanosheets for Water Dissociation

Hollow Cuboidal Metal Oxide-Based Asymmetric Electrode Configuration for High-Performance Anion Exchange through Quaternized Pyridine-Poly(vinyl alcohol) @ Metal Hydroxide Nanosheets for Water Dissociation