Current Opinion in Electrochemistry

On the nature of adsorbed species on platinum single-crystal electrodes

The dependence of voltammetric currents on multiple parameters (concentration, pH, temperature, etc) has become a primary source of information in interfacial studies of noble metal electrodes. Peak potential, charge, and width are intimately related to surface structure and reactivity. However, this interpretation usually neglects the complexity of the redox processes involved. For the so-called hydrogen adsorption region in platinum, anion competitive adsorption plays an important role that is usually overlooked. While charge displacement already demonstrated decades ago the existence of anion adsorption contributions, only recently a combination of several surface-sensitive techniques has proven unambiguously the presence of OH adsorbed on step sites at potentials much lower than usually considered. This information must not be neglected when analyzing the properties of complex catalysts, such as those composed of nanoparticles, since it is of great importance for understanding its overall reactivity, comparing with computational results, and performing coulometric analysis.

Electrochemical Gut-on-Chip systems as the next generation platforms for studying mucosal redox biology

Highlights • The redox sensitive mucus is affected by oxygen gradients, effecting gut physiology. • Demonstrating oxidative homeostasis is crucial to mimic cell-bacteria communication. • Organ-on-Chip systems lack the complexity to mimic the redox state in the mucus. • Electrochemical sensors and redox mediators may assist mimicking the mucosa layer. Within the gastrointestinal tract, the mucosal layer, which is the physical and homeostatic barrier between the microbiome and the host, exhibits redox molecules such as mucin molecules and oxidative species generating oxygen gradient. These molecules control the mucosal structural state and affect cross-communication in the microbiome. Gut-on-Chip platforms are Organ-on-Chip devices that tend to imitate gut physiology; however, the crucial oxidative state in the epithelial-microbiome barrier is not well represented in these platforms. The ability to properly mimic the gentle communication between the prokaryotic and eukaryotic kingdoms in the gut requires contemporary electrochemical and Organ-on-Chip tools. In this review article, we highlight the redox-dependent functional states in the mucosal layer, discuss the current advancements in Gut-on-Chip devices, present the challenges remaining in such devices to properly mimic the mucosa layer, and recommend an innovative approach involving the integration of label-free electrochemical sensors within the Gut-on-Chip platform. Graphical abstract Download : Download high-res image (359KB) Download : Download full-size image

Organic electrosynthetic processes using solid polymer electrolyte reactor

To achieve carbon neutrality by 2050, there is an urgent need to transition from major power sources to renewable energy and electrify various manufacturing technologies. This is also inevitable in the production of basic organic chemicals, which are used as raw materials in pharmaceuticals and agrochemicals, entailing organic chemical production processes that significantly reduce heat consumption. Therefore, the electrosynthesis of organic chemical products, as an enabling technology for electrification in the chemical industry, has received considerable attention. This study outlines the history, features, and challenges involved in organic electrosynthesis and introduces organic electrosynthetic processes using solid polymer electrolyte (SPE) reactors, which have the potential to realize carbon neutrality. Graphical abstract Download : Download high-res image (182KB) Download : Download full-size image

Electrochemical Gut-on-Chip systems as the next generation platforms for studying mucosal redox biology

Highlights • The redox sensitive mucus is affected by oxygen gradients, effecting gut physiology. • Demonstrating oxidative homeostasis is crucial to mimic cell-bacteria communication. • Organ-on-Chip systems lack the complexity to mimic the redox state in the mucus. • Electrochemical sensors and redox mediators may assist mimicking the mucosa layer. Within the gastrointestinal tract, the mucosal layer, which is the physical and homeostatic barrier between the microbiome and the host, exhibits redox molecules such as mucin molecules and oxidative species generating oxygen gradient. These molecules control the mucosal structural state and affect cross-communication in the microbiome. Gut-on-Chip platforms are Organ-on-Chip devices that tend to imitate gut physiology; however, the crucial oxidative state in the epithelial-microbiome barrier is not well represented in these platforms. The ability to properly mimic the gentle communication between the prokaryotic and eukaryotic kingdoms in the gut requires contemporary electrochemical and Organ-on-Chip tools. In this review article, we highlight the redox-dependent functional states in the mucosal layer, discuss the current advancements in Gut-on-Chip devices, present the challenges remaining in such devices to properly mimic the mucosa layer, and recommend an innovative approach involving the integration of label-free electrochemical sensors within the Gut-on-Chip platform. Graphical abstract Download : Download high-res image (359KB) Download : Download full-size image

Editorial Overview: Physical and Nanoelectrochemistry (2023) An Electrochemical Perspective on How We Know What We Don`t Know

Electrosynthesis with split-bipolar electrodes

Highlights • The principles of split-bipolar electrodes are discussed. • Split-bipolar electrodes are described in relation to conventional bipolar electrodes. • The use of split-bipolar electrodes for electrochemical fluorination of small organic molecules is summarized. • The use of split-bipolar electrodes for electrosynthesis of conducting polymers is summarized. Bipolar electrochemistry has recently gained renewed interest as a valuable electrochemical technique for electrosynthesis applications. The peculiarity of this technology is the wireless mode of electrode reactions, that is redox processes can be driven on a conductive material, namely a bipolar electrode (BPE), without the need for an ohmic contact. A split-BPE (s-BPE) is a particular type of BPE, where two conductors are connected using an ammeter that is placed outside the electrolytic solution. While this configuration allows the two conductors to behave like a single BPE, the main advantage of such a system is that the current can be measured in situ, promoting the search for the optimized set of conditions for a successful electrosynthesis application. Herein, we review the latest trends in electrifying synthesis that exploit the concept of s-BPE for electrosynthesis of polymeric materials and electrochemical fluorination of small organic molecules.