Diffusion Layer Thickness Research Articles

Electrode Spacing Effects on the Capacitance of Glassy Carbon Electrodes in Aqueous Electrolytes

Matched glassy carbon electrodes in aqueous K2SO4 electrolytes were used to examine the effects of opposing electrode spacing on capacitive performance. Planar non-porous glassy carbon electrodes were used to avoid complications with porosity and roughness. Electrode spacing effects were examined in terms of device and individual electrode performance, using cyclic voltammetry, coupled with its deconvolution into residual, diffusional, and capacitive processes. Decreasing the spacing between electrodes led to a decrease in capacitive contributions, and a relative increase in diffusional and residual contributions, implying that individual electrodes were influencing the behaviour of each other. This is also consistent with the use of more dilute electrolytes. Electrode behaviour was modelled using the Poisson-Boltzmann equation, together with its integrated outputs of electric field and potential difference. For electrodes with the same amount of charge and a similar diffuse layer thickness, the electric field and potential drop was diminished because of their charge interaction. Conversely, it is shown that for a similar potential drop across the electrodes, the variable controlled in a cyclic voltammetry experiment, more charge accumulation is needed at the electrode-electrolyte interface to compensate for the counter charge generate from the opposing electrode.

A novel plating bath device for reducing surface copper thickness and improving wafer-scale uniformity

Through silicon via (TSV) technology plays a pivotal role in three-dimensional integrated circuits. However, excessive surface thickness and uneven wafer plating during TSV copper electroplating pose significant challenges to TSV reliability. This paper proposes a novel rotating cathode electroplating technique that utilizes flow field induction by a rotating cathode to significantly reduce the surface copper thickness by approximately 8 μm, leading to improved uniformity of wafer-scale electroplating and facilitating rapid TSV filling. This study focuses on the impact of cathode rotation speed and chip position on TSV filling quality. The experimental findings demonstrate that increasing the cathode rotation speed reduces the diffusion layer thickness, thereby enhancing filling quality. Additionally, variations in chip position influence surface copper thickness. The introduction of bis(3-sulfopropyl) disulfide accelerant expedites the filling process, boosts the filling ratio, and enables defect-free TSV filling. This study offers valuable insights into the wafer-scale TSV electroplating process and facilitates the optimization of parameter settings during electroplating.

Effect of annealing on the microstructure and mechanical properties of Al/Zn composite plates

The study examined how various annealing methods affect the structure and characteristics of Al/Zn layered composite plates. Four distinct composite plates underwent annealing at temperatures of 160 °C, 200 °C, and 240 °C for durations ranging from 0.5 h, 1 h, 1.5 h, and 2 h. Changes in grain structure, interface appearance, and thickness of the interface diffusion layer were analyzed using metallographic microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). Tensile and microhardness tests were performed under different annealing conditions and cycling durations. Results showed that as annealing time increased, tensile strength initially rose before declining, while elongation remained consistently high. The optimal balance between strength and ductility was observed at 200 °C for 1.5 h of annealing across all plate types. Before annealing, Al displayed a fractured ultrafine crystalline structure, while Zn's texture underwent changes.

A Refined Thin-Film Model for Drug Dissolution Considering Radial Diffusion - Simulating Powder Dissolution.

We aim to present a refined thin-film model describing the drug particle dissolution considering radial diffusion in spherical boundary layer, and to demonstrate the ability of the model to describe the dissolution behavior of bulk drug powders. The dissolution model introduced in this study was refined from a radial diffusion-based model previously published by our laboratory (So et al. in Pharm Res. 39:907-17, 2022). The refined model was created to simulate the dissolution of bulk powders, and to account for the evolution of particle size and diffusion layer thickness during dissolution. In vitro dissolution testing, using fractionated hydrochlorothiazide powders, was employed to assess the performance of the model. Overall, there was a good agreement between the experimental dissolution data and the predicted dissolution profiles using the proposed model across all size fractions of hydrochlorothiazide. The model over-predicted the dissolution rate when the particles became smaller. Notably, the classic Nernst-Brunner formalism led to an under-estimation of the dissolution rate. Additionally, calculation based on the equivalent particle size derived from the specific surface area substantially over-predicted the dissolution rate. The study demonstrated the potential of the radial diffusion-based model to describe dissolution of drug powders. In contrast, the classic Nernst-Brunner equation could under-estimate drug dissolution rate, largely due to the underlying assumption of translational diffusion. Moreover, the study indicated that not all surfaces on a drug particle contribute to dissolution. Therefore, relying on the experimentally-determined specific surface area for predicting drug dissolution is not advisable.

Microstructural and mechanical characterization of Al/Cu interface in a bimetallic composite produced by compound casting

The bimetal set (Al/Cu) with Cu wire with 2.0, 2.5, and 3.0 mm diameters were cast at different casting temperatures and solidification times through the compound casting method. The microstructure of solid/liquid diffusion bonding at the Al/Cu interface was investigated, and the shear strength of the Al/Cu interface was measured by punch test. By characterizing the diffusion layer, the optimum parameters of the compound casting, including the casting temperature and the solidification soaking time, as well as the Cu wire diameter, were acquired. The intermetallic compounds (IMCs) such as CuAl2 were observed in the diffusion layer. The types of intermetallic phases and diffusion layer thickness affect the hardness and the shear strength. The result of casting at 680 °C and solidification soaking time of 15 s for 3 mm Cu wire, shows that IMCs increased the micro-hardness of the Al/Cu bimetal up to 328 HV at the Al/Cu interface. Also, increasing the solidification soaking time at a constant temperature resulted in a growth of the interface layer’s thickness, which exhibits a lamellar eutectic microstructure containing IMCs. Furthermore, this action caused an increase in the shear strength.

Interface behaviors and mechanical properties of diffusion bonded 45 steel/additive manufactured 316L steel joints

Diffusion bonding of additive manufactured (AM) metal parts to traditionally manufactured metal parts could simultaneously achieve large-scale, complex-structure, and multi-material parts. However, there is a lack of study on diffusion bonding as well as its interface formation mechanism between AM metal parts and traditionally manufactured metal parts. In this study, diffusion bonding was performed to join AM 316L stainless steel and casting 45 steel at different temperatures. The element distribution, interface characteristics and shear strength of the joints were investigated, and the interface formation mechanism at different bonding temperature was analyzed in detail. The results reveal that the interface transition zone from the AM 316L steel side to the 45 steel side is composed of the metallic elements diffusion layer and the carbide layer. Moreover, an increase in bonding temperature can effectively promote interface voids closure and increase the thickness of the metallic elements diffusion layer, while the thickness of the carbide layer firstly increases and then decreases as the temperature increases. The component of the carbide layer was identified as brittle compounds (CrFe)23C6 and (CrFe)7C3. The shear strength of the joints exhibited an increasing trend with the increasing bonding temperature. Interestingly, a sudden decrease in strength was found at 950 °C due to the significant increase of the brittle carbide layer, while high-quality joints could be achieved as the brittle carbides dissolve at 1000 °C. This study could lay the foundation for understanding diffusion bonding interface behaviors between AM metal parts and traditional casting metal parts.

Development of a physiologically-based pharmacokinetic model to simulate the pharmacokinetics of intramuscular antiretroviral drugs.

There is growing interest in the use of long-acting (LA) injectable drugs to improve treatment adherence. However, their long elimination half-life complicates the conduct of clinical trials. Physiologically-based pharmacokinetic (PBPK) modeling is a mathematical tool that allows to simulate unknown clinical scenarios for LA formulations. Thus, this work aimed to develop and verify a mechanistic intramuscular PBPK model. The framework describing the release of a LA drug from the depot was developed by including both the physiology of the injection site and the physicochemical properties of the drug. The framework was coded in Matlab® 2020a and implemented in our existing PBPK model for the verification step using clinical data for LA cabotegravir, rilpivirine, and paliperidone. The model was considered verified when the simulations were within twofold of observed data. Furthermore, a local sensitivity analysis was conducted to assess the impact of various factors relevant for the drug release from the depot on pharmacokinetics. The PBPK model was successfully verified since all predictions were within twofold of observed clinical data. Peak concentration, area under the concentration-time curve, and trough concentration were sensitive to media viscosity, drug solubility, drug density, and diffusion layer thickness. Additionally, inflammation was shown to impact the drug release from the depot. The developed framework correctly described the release and the drug disposition of LA formulations upon intramuscular administration. It can be implemented in PBPK models to address pharmacological questions related to the use of LA formulations.

Content and Dispersion of Ferroalloys in the Coating During Microarc Alloying of Steel

Introduction. The main disadvantage of traditional processes of diffusion surface hardening of steel products is its long duration. Therefore, the problem of intensification of such processes is relevant. To solve it, the use of high-energy effects on the material is proposed, which allows us to obtain a hardened surface layer from a coating composed of ferroalloy powders containing alloying elements. There is no data in the literature on the required content and dispersion of such powders in the composition of the coating. The aim of this study was to select the particle size of ferroalloys and their concentration in the coating to achieve the most effective hardening of the processed product.Materials and Methods. For experimental studies, cylindrical samples made of steel 20 with a diameter of 12 mm and a length of 35 mm were used. On the surface of these samples, an alloying coating containing ferroalloy powders and an electrically conductive gel as a binder was applied. After that, the samples were immersed vertically for half their length into a metal container, which was then filled with carbon powder with a particle size of 0.4–0.6 mm. Then an electric current of 2.5 to 3.0 A was passed in the circuit power source — container — carbon powder — sample. The duration of the process was 2–8 minutes.Results. The calculated estimation of the electrical conductivity of coal powder was performed, and the thermophysical parameters of microarc heating of steel were calculated. These include the power released by electric current on the surface of the steel product, the density of the heat flux, and the energy of a single microarc discharge. The expressions for calculating the particle size of ferroalloy powder were obtained, as well as the experimental dependencies of the diffusion layer thickness on the particle size of ferroalloys and their content in the coating.Discussion and Conclusion. The results of this study have allowed us to determine the size range of ferroalloys and their content in the coating. This information is essential for optimizing the alloying process and ensuring the most efficient surface hardening treatment for steel products. The data collected will be used to develop improved technological processes for the surface hardening process, leading to improved product quality and performance.

Membrane behavior of clay under mixed solution conditions

Compacted clay is employed as the buffer material for landfills, and multiple ions are dissolved in the leachate restricted by the compacted clay layer. The membrane efficiency is an important indicator to assess the barrier properties of the compacted clay layer and is measured through membrane tests. However, most membrane tests are currently conducted with a single solute solution, which does not reflect the mixed solution characteristics of leachates. To assess the membrane efficiency of compacted clay under mixed solution conditions, 13 membrane tests were conducted on a bentonite-amended soil using KCl–NaCl mixed solutions, KCl–CaCl2 mixed solutions, and KCl–AlCl3 mixed solutions with different mixing ratios at a total concentration of 20 mM. Nuclear magnetic resonance (NMR) tests were conducted on the soil specimen after the membrane tests to investigate the micromechanism of the membrane behavior under mixed solution conditions. Results indicate that the membrane efficiency increased with the mixing ratio of Na+ but decreased with the mixing ratio of Ca2+ or Al3+. In the 13 membrane tests, the lowest membrane efficiency was achieved when the specimen was tested with pure AlCl3 solution. The relationship between the membrane efficiency and mixing ratio was also investigated at the microscopic scale. As the ion valence increases, the diffuse double layer thickness is smaller and the proportion of macropores is larger, as verified by NMR tests.

Fines migration characteristics of illite in clayey silt sediments induced by pore water under the depressurization of natural gas hydrate

Marine gas hydrate is widely distributed in clayey silt sediments, which have high clay content and low permeability. The decomposition of natural gas hydrate will cause the mechanical failure of the reservoir and the decrease of pore water salinity, inducing the migration of clay minerals to clog the pore throat, which has a significant impact on the production efficiency of natural gas hydrate. In this work, the migration behaviour of illite in clayey silt sediments driven by pore water under the depressurization of hydrate was studied through pressure difference, pore throat and content changes. We studied the migration process of silt, excluding the interference of synergistic migration of silt and illite, and then studied the migration of illite under the change of flow rate and salinity. The results show that illite will migrate before silt and that critical flow rate and critical salinity exist. The flow rate mainly affects the torque generated by the forces detaching the illite particles. Illite particle detachment will occur if the flow rate exceeds the critical value and the torque balance is disrupted, and then the pore throat is clogged. There are two effects of salinity decrease on illite migration. Above the critical salinity, the expansion of the pore throat due to decomposition has a significant effect on illite migration. Below the critical salinity, the increase of the diffuse electric double layer thickness and the electrostatic repulsion will lead to an increase of the particle concentration in the pore water, making clogging more likely to occur even at low flow rates. This work suggests that clay migration has a complex impact on the development of clayey silt hydrate, and helps to consider the reasonable combination of saturation and production rate when designing a development plan to reduce the impact of permeability decline due to continuous pore throat clogging on development efficiency.

Optimization of gas diffusion layer thickness for high-temperature proton exchange membrane fuel cells

Optimization of gas diffusion layer thickness for high-temperature proton exchange membrane fuel cells

In English

The influence of the Nernst diffusion layer thickness on the surface concentrations of electroactive and electroinactive species in a model electrochemical process with a preceding homogeneous first-order chemical reaction under application of a small amplitude alternating current has been investigated. A case of equal diffusion coefficients of species taking part in the preceding chemical reaction in a thin layer attached to a planar electrode is considered. It has been shown that, at low frequencies of an applied alternating current, the surface concentrations of electroactive and electroinactive species increase with increasing the Nernst diffusion layer thickness. At high frequencies, the surface concentrations of both species do not depend on this parameter. However, there is a range of frequencies where the surface concentrations of species can decrease with increasing the Nernst diffusion layer thickness. This range of frequencies can be influenced by a value of the Nernst diffusion layer thickness, the rate constants of chemical reaction, and the diffusion coefficient of species. There exists a phase shift between an alternating current and the surface concentrations of electroactive and electroinactive species that change under application of this current. It is a function of the Nernst diffusion layer thickness, the oscillation diffusion layer thickness, and the reaction layer thickness. In the case of electroactive species, the phase angle can take only a positive value. At low frequencies, it tends to π/2, whereas at high frequencies it decreases to π/4. For the case of electroinactive species, the phase angle can be positive, negative, and equal to zero depending on the value of the Nernst diffusion layer thickness, the rate constants of chemical reaction, and the diffusion coefficient of species. It approaches –π/2 at low frequencies, and at high frequencies it tends to π/4. The both phase angles can have the maxima and the minima. Their values are strongly dependent on the Nernst diffusion layer thickness, the diffusion coefficient of species, the rate constants of chemical reaction.

Decoupling Reaction, Diffusion and Ohmic Processes in Fast-Charging Electrodes: A New Model for CV Data Analysis

Fast charging is critical for the efficient storage of energy in devices like electric vehicles and portable electronics. The rate performance of electrodes is limited by the electron transfer rate, the ohmic resistance of the electrode, the size and shape of the primary electrode particles, and the charge carrier diffusion process within the electrodes. However, separating the intrinsic contributions of mass transport and charge transfer from non-equilibrium data obtained under large interfacial polarization is very complex, which limits our understanding of high rate electrodes during charging and discharging. While it is possible to extract the diffusive and capacitive components of an electrode’s capacity from cyclic voltammetry (CV) data using the Dunn method, the Dunn model assumes a constant diffusional overpotential. In reality the ohmic resistance scales with the current, so that the ohmic potential drop across the electrode cannot be neglected a priori for fast charging electrodes in which high current densities are a requirement.We recently developed a new model based on the Butler-Volmer equation for the kinetics of the electron exchange process, and incorporated the charge carrier diffusion process and the internal ohmic losses, as well as the effect of the shape and dimensions of the primary electrode particles on the effective diffusion rate [1]. The model can provide the relation between current peak voltages and peak currents from a series of sweep rate CV measurements. The ohmic resistance, equilibrium voltage, exchange current (related to the electrochemical reaction rate) and limiting current (related to the charge carrier diffusion coefficient and Nernst diffusion layer thickness) can be extracted as independent variables from the fitted experimental data.By simulating a range of different high rate Li electrode materials (both cathodes and anodes), we identified influence of the reaction rate on the overpotential as a common significant factor, which explains the nonlinear relation between the potential and the current at peak position in different CV measurements. Our analysis suggests that a higher electrochemical reaction rate seems to be more important for the realization of faster charging batteries than a larger carrier diffusion coefficient.Finally, our extended model also enables us to predict the overpotential at any applied potential, which is not possible with other current models known till date. This insight helps us to gain more detailed understanding of the relationship between the intrinsic properties of the electrode materials and their rate performance in different reaction stages. This may facilitate further modification of electrode material towards enhanced high rate performance in next-generation batteries.[1] R. Xia et al., Energy Storage Mater. 53 (2022) 381-390.

In-Situ Observation of the Formation and Relaxation Processes of Concentration Gradients in a Lithium Bis(fluorosulfonyl) Amide–Tetraglyme Solvate Ionic Liquid Using Digital Holographic Interference Microscopy

Introduction Next-generation Lithium-ion batteries (LIBs) require fast charge–discharge operations, during which a steep concentration gradient (CG) is formed between the two electrodes. The formation of a concentration profile between the electrodes in an LIB with a solvate ionic liquid (SIL) is observed at a distance of less than 1 mm using holographic interferometry. This in situ technique enables the visualization of concentration profile formation near both electrodes during electrolysis, which relaxes after the electrolysis is stopped. The diffusion coefficients near both the electrodes are calculated from the concentrations of transient species near the electrode surfaces. The diffusion coefficient is smaller on the anode side of the cell than that on the cathode side owing to the viscosity of the electrolyte in the diffusion layer. This viscosity effect may have caused the concentration profile to become asymmetrical during the relaxation of the CG. Experimental Li metal was used for the anode and cathode. The distance between the electrodes was 600 μm. The electrolyte was a SIL mixture of LiFSA (lithium bisfluorosulfonylamide) and G4 (tetraglyme) at a molar ratio of 1:1. After 100 seconds of Li electrodeposition and dissolution at a constant current density (3 mA cm-2), the current was stopped, and the relaxation process of the concentration gradient generated by electrolysis was observed with a laser interference microscope (Lyncee Tec) for 1700 seconds. The Li+ concentration near the electrode was calculated from the optical phase difference based on the bulk electrolyte outside the diffusion layer. The electrode surface concentration and transference number of Li+ were used to obtain the diffusion coefficients of Li+ near both electrodes. The time variation of the diffusion layer thickness during and after electrolysis was measured to study the mass transfer phenomenon during the formation-relaxation process of the concentration gradient.

FRACTAL MODEL OF FLOW CURRENT IN MICRO ROUGH CAPILLARY TUBES

Based on the fractal geometry science and the model of flow friction resistance when fluid flows through rough microcapillaries, the formula of diffusion layer thickness and the spatial charge density distribution of the pipe were derived. The relationship between the amount of space charge and the structural parameters of rough elements, relative roughness, liquid conductivity, pipeline diameter, and other physical quantities was discussed. It was found that the height of rough elements is directly proportional to the thickness of the diffusion layer, and also positively proportional to the amount of current. The predicted results of the model are in good agreement with existing models and various published experimental data, verifying the accuracy and reliability of the model.

Prediction of Oxygen Distribution in Silos and Chambers Filled with Various Agricultural Commodities

In the context of post-harvest pest management in agricultural products, the adoption of modified atmospheres presents an eco-friendly alternative to conventional pesticides. This study focuses on nitrogen gas as a potential agent for insect control in stored commodities, utilizing computational simulations (by employing the convection–diffusion equation) to investigate its penetration and distribution within two common storage configurations: chamber-contained pallets and silos. The results highlight the influence of boundary conditions, commodity porosity, and convection effects on nitrogen dispersion. In chamber scenarios, the first boundary condition considers that pallets are placed inside a chamber with uniform (99.5%) nitrogen concentration, whereas in the second one, the concentration gradually increases from 78% to 99.5%. The average duration required for O2 concentration to reach 1% is approximately 10.7 h and 133.3 h for the two boundary conditions, respectively. Among the agricultural commodities, walnuts (kernels) exhibit the shortest duration, while prunes require the longest time. In silos, convection and diffusion interact to establish a consistent diffusion layer thickness. Most agricultural products exhibit similar behavior, with average times of 13.5 h, 25.4 h, and 37.0 h for three heights (10 m, 20 m, and at the silo’s top at 30 m), respectively.

Effects of structural parameters of double-layer electrode on co-electrolysis in a solid oxide electrolysis cell

The advantages of double-layer electrode are available in the literature about single electrolysis of H2O and CO2 using solid oxide electrolysis cell (SOEC). However, for the co-electrolysis of CO2 and H2O, the influence of the structural parameters of the double-layer electrode on the co-electrolysis performance has been still unclear. In this study, a multi-scale model describing the co-electrolysis process of CO2 and H2O in SOEC is adopted. After model validation, a comparison of the performance of SOEC between a single-layer cathode and a double-layer cathode is conducted with different inlet flow rates. Moreover, parametric analyses are performed to investigate the effects of the thickness and porosity of cathode diffusion layer (CDL) and the internal composition of cathode function layer (CFL). The results show that when the CDL porosity increases from 0.45 to 0.65, the conversion ratio of H2 and CO increase by 10.17 % and 10.24 %, respectively. The optimal thickness of CDL (200 μm) for enhancing the durability of the cell and the preferable internal composition of CFL for improving the co-electrolysis performance are found within the scope of this study. This numerical analysis can provide guidance for the design of the double-layer cathode and the optimization of the co-electrolysis performance.

Electrochemical detoxification of tetrabromobisphenol A-contaminated water using Ti/SnO2-Sb/PbO2-Ce anodic membrane

Degradation of refractory organics has been limited by their low mass-transport rates in conventional flow-by operated electrochemical reactors. This study explores for the first time the development of porous titanium (Ti)-based metal oxide anodic membrane for efficient flow-through degradation of recalcitrant tetrabromobisphenol A (TBBPA). For this purpose, a duplexed Ti/SnO2-Sb/PbO2-Ce anodic membrane was successfully prepared by sol-gel and electrodeposition methods. Ti/SnO2-Sb/PbO2-Ce exhibited improved mechanical and electrochemical stability, larger electrochemical surface area, higher oxygen evolution potential and lower charge transfer resistance, as compared to its mono-layered rival (Ti/SnO2-Sb). The switching from flow-by to flow-through operation resulted in an increased mass transfer rate constant and narrowed diffusion layer thickness of Ti/SnO2-Sb/PbO2-Ce. In the flow-through mode, Ti/SnO2-Sb/PbO2-Ce enabled the complete TBBPA removal at a relatively low electric energy (0.11 kWh m−3). The TBBPA removal was ascribed to the direct anodic oxidation and indirect anodic oxidation incurred by absorbed HO, free HO and 1O2. The intermediate products, which were arisen from the attack of TBBPA by these reactive species, were identified. We further estimated their acute toxicities and bioaccumulation factors. This research proposed a robust electrochemical filtration approach for detoxification of TBBPA-contaminated water.

Effect of Food Viscosity on Drug Dissolution.

The purpose of the present study was to investigate the effect of food viscosity on the dissolution rate of a drug. There are two types of viscosity, macroviscosity and microviscosity. Macroviscosity affects the diffusion layer thickness, whereas microviscosity affects the molecular diffusion coefficient. The mass transfer coefficient (kc) in the intrinsic dissolution rate (IDR) depends on the viscosity (η) as kc ∝ ηa (a is an exponent on η). In theory, for rotating flow over a disk, if a thickener increases only macroviscosity, a = -1/6, and if it increases both macroviscosity and microviscosity equally, a = -7/6. Benzocaine was used as a model drug. Hydroxypropyl cellulose (HPC) and methylcellulose (MC) were employed as control thickeners that increase only macroviscosity. Sucrose was employed as a control thickener for both macroviscosity and microviscosity. The FDA breakfast homogenate (BFH) was diluted with distilled water or 1mM HCl with/without pepsin digestion. The IDR value was measured by the paddle-over-disk method. The η value of 30% BFH distilled water was 209mPa∙s, about 300 times higher than distilled water. It was further increased by HCl (430mPa∙s), and reduced by pepsin digestion (35mPa∙s). The kc value was little affected by BFH (a = 0.00 to -0.09), slightly less than those in HPC (a = -0.19) and MC (a = -0.21). Sucrose decreased the kc value more significantly (a = -0.70). The IDR and kc values of benzocaine were little affected by BFH, suggesting that BFH increased only macroviscosity.

A novel electrochemical method determining pKa and transport parameters of buffers using acid-base transport limitation response

Dissociation constant (logarithmic form, pKa) and diffusion coefficient (D) are two fundamental physical parameters for weak acids and bases (buffers). Their effortless determinations from one method are not available yet. Herein, we propose an innovative method to determine pKa and D values based on a brand-new principle of electrochemical acid-base transport limitation (eABTL). The significance of eABTL lies in its ability to relate inert buffers to electrode reactions, enabling the acquisition of electrochemical responses for inert species. Acid-base transport limiting current (jl) is the only variable that needs to be measured. The pKa and transport coefficient (m) are determined from the relationship of jl vs. solution pH and jl vs. buffer concentration, respectively. Three ways are available for D determinations by introducing the expressions of diffusion layer thickness. The method is demonstrated using rotating disc electrodes to implement hydrogen evolution reaction. The pKa, m and D values exhibit good repeatability in multiple determinations. A well-defined electrode geometry is necessary for accurate D determination. This method can be developed to a family of methods with the advantages for fast estimating practical parameter values of buffers.