Modeling electrochemical systems and insights for modern electrochemists.
Key Concepts Oxygen Diffusion: Describes mass transport from the membrane to the electrode and determines the sensor current. Chamber Geometry: Describes the diffusion path length and influences both current magnitude and response time. Membrane Permeability: Determines how efficiently oxygen enters the sensor through the membrane. Introduction The most common way to measure oxygen dissolved by…
Oscillatory chemical reactions attract both researchers and enthusiasts because of their interesting pattern formation and oscillating colour changes, which contrast to conventional chemical reactions. However, their discovery was initially met with strong resistance from the scientific community. A brief history By the early 1920s Lotka[1] developed a simple model using two sequential…
Key Concepts Enzymatic Kinetics: Controls the rate of glucose oxidation through a sequence of coupled chemical reactions. Enzyme Saturation: At high glucose concentrations, the enzyme is saturated limiting the reaction rate. Indirect Detection: Glucose is not measured directly; instead, the current arises from the oxidation of hydrogen peroxide (H 2 O 2 ) produced during the enzymatic reactions.…
The iR drop , also known as the ohmic drop , refers to the reduction in effective potential at the working electrode interface due to the resistance of the electrolyte solution. This drop affects both the potential applied by the potentiostat and the potential it measures, thereby distorting the observed electrochemical response. In the absence of mass transport limitations, the redox reaction can…
Key Concepts Adsorption: Electroactive species can be adsorbed at the electrode surface, affecting the shape and intensity of the voltammogram. Coupled Processes: Adsorption and faradaic reactions occur simultaneously, each governed by distinct charge transfer kinetics. Scan Rate Dependence: Adsorption effects are strongly affected by the scan rate, impacting peak position, shape, and current…
Traditional electrochemical methods are crucial for observing reactions at electrodes but face several limitations: Capacitance currents: Each time the electrode is polarized, it acts like a small capacitor, creating extra current that can interfere with the measurement data. Lack of Specificity: Unless the electrode is specifically functionalized, reactions at the electrode–water interface are…
In many cases, electrochemical systems are more complex than a simple interfacial electron transfer and may involve coupled chemical reactions. The presence of homogeneous chemical reactions in conjunction with the electrode process can significantly impact the electrochemical response of the system. In this blog, we will explore the scenario where a homogeneous first-order reaction is followed by…
Key Concepts Butler–Volmer Kinetics: The rate of charge transfer at the electrode–electrolyte interface depends exponentially on the applied overpotential. Mass Transport: The current response in cyclic voltammetry is governed by the diffusion of electroactive species from the bulk solution to the electrode surface. Reversibility: Determined by the relative rates of oxidation and reduction; fast…