Electrochemical science advances最新文献

Electrolysis is a dynamic research area in which both mature and new promising processes, such as alkaline water electrolysis and electrochemical CO₂ reduction, are under enormous development pressure due to their high relevance for the energy sector. High-throughput (HT) technologies are efficient screening platforms that can accelerate research activities and significantly shorten development times. Over the past 25 years, various HT platforms have found their way into electrochemical research. These typically have one or more major disadvantages: they are characterized by abstract experimental conditions, designed for a specific application or process, or generate insufficiently comparable data. In this publication, we present a newly developed HT test system that enables the parallel operation of 16 electrochemical bench-scale flow cells under industry-relevant test conditions. The specially developed modular flow cell can be operated variably in the fully automated system and allows research into the most common applications in electrochemistry for many different processes with a focus on all relevant variants of water electrolysis and electrochemical CO₂ reduction. Both the HT system and the developed flow cell are designed to accelerate the generation of reliably reproducible data with high comparability in order to strengthen scientific exchange. The fully automated process control, online analysis and programmable feedback loops of the HT test system provide great potential for the design of experiment strategies. The implementation of Design of Experiment strategies will maximize the testing efficiency of this innovative research system.

The electrochemical reduction of carbon dioxide (eCO₂RR) is a promising technology for synthesizing value-added products required in the transition towards a more circular and renewable-based economy. In this context, the electrochemical production of formic acid has the potential to become economically competitive to energy-demanding conventional synthetic methods, thereby presenting a sustainable alternative. However, to enhance energy efficiency and selectivity toward the targeted product significant technological improvements in key components (e.g., electrodes, catalysts, electrolytes, membranes, cells, solvents) are required. Over recent years, our research has focused on understanding the influence of catalyst, gas diffusion electrode (GDE) architecture and performance, and cell design in the eCO₂RR to formic acid. This perspective article provides an overview of the current status of these specific components, as well as our insights and those of other researchers, regarding potential future investigations and applications.

This work reports a methodology for the fabrication of Pt thin-film electrodes for electrochemical studies in hydrothermal systems. The research process was meticulous, with particular attention paid to the multilayer Ti/Pt/Ti/Al₂O₃ film structure and annealing conditions that are expected to impact the morphology of the films, surface composition and electrochemical response. The findings of this study are significant, as they provide valuable insights into the behaviour of Pt thin-film electrodes in various media and conditions. Two different approaches were adopted for the preparation of the electrodes: in one case, the Ti/Pt/Ti/Al₂O₃ films deposited on sapphire wafers were exposed to rapid thermal annealing at 900°C under argon for 5 min, followed by argon ion milling to etch the final electrode pattern (Pt-RA(900)), while in the other case, uncapped Pt films were annealed, after etching, in a tubular oven under argon at specific temperatures between 200°C and 900°C (Pt-TO). Rapid annealing at 900°C on capped films resulted in the formation of a Pt₃Ti intermetallic alloy with remarkable mechanical and chemical stability even after 10 h of immersion in deionised water, acid (0.1 M H₂SO₄) and alkaline media (0.1 M KOH) conditions at temperatures up to 150°C, despite the dissolution of the Al₂O₃ top layer at 150°C and long immersion times (> 10 h). In the case of uncapped Pt films, diffusion and oxidation of Ti through the Pt film at high temperature resulted in the formation of TiO₂ on the surface of Pt. The results were confirmed by using a comprehensive suite of ex-situ characterisation techniques to follow changes in the Pt electrode surface morphology and composition before and after immersion in H₂O, 0.1 M H₂SO₄ and 0.1 M KOH solutions under argon. Ex-situ electrochemical characterisation studies were also conducted to correlate the changes in the electrode surface properties, including the electrochemical surface area, with different annealing conditions and after various hydrothermal treatments in neutral, alkaline and acidic media.

Ethanol is a promising product for the carbon dioxide reduction reaction (CO₂RR), as ethanol as a value-added product can help to enable the near-term feasibility of this technique, thus Power-to-ethanol can act as a pioneering process for the CO₂RR. Furthermore, CO₂RR offers a green production process for ethanol in addition to biomass fermentation. However, the formation of ethanol via electrolysis often competes with ethylene production, which makes the selective formation of ethanol more difficult. We show that this problem can be circumvented by using a bimetallic catalyst that provides abundant *CO and thus activates an alternative and selective reaction path for ethanol. However, this study was carried out in an aqueous-fed H-type electrolyzer, which has mass transport limitations and thus insufficient current densities. To solve this issue, the studied catalyst is transferred to a gas diffusion electrode. Here we emphasize that, in addition to other relevant parameters, the choice of the binder also can have a high impact on the performance of the electrode. As an outlook, various enhanced reactor designs and their influence on ethanol formation are presented.

In this study, the electrochemical behaviour of phosphine in sulphuric acid solutions on the surface of various electrode materials was conducted by voltammetric investigations. The effects of electrode materials such as lead, copper, and platinum electrodes on the PH₃ anodic oxidation were investigated. Polarization curves were recorded by saturating the sulphuric acid solution with phosphine. The results received show that the electrochemical oxidation of phosphine on the lead electrode is accompanied by an oxygen evolution potential and, on the copper electrode, copper (II) ions show catalytic effects. The maximum anodic oxidation of phosphine on a platinum electrode was observed at the potential range of 0.8–1.0 V, and in the presence of copper (II) ions on the polarogram a maximum of phosphine oxidation is recorded at a potential of approximately 0.1–0.2 V.

Lactate is a useful analytical indicator in various fields. The lactate monitoring benefits from evaluating the body's condition, as excessive muscle use or fatigue can result in injury. Further, it is useful for alerting to emergencies like haemorrhage, hypoxia, respiratory distress, and sepsis. Additionally, the determination of the food's lactate level is very important in examining freshness, storage stability, and fermentation degree. Given such benefits, the determination of lactate in various samples has been widely explored, especially using electrochemical sensor technology. Despite enzymatic sensors being the focus of numerous studies, enzyme-free platforms have gained focus over the last few years to address the matter of enzyme stability. This review article respectfully offers an overview of the concepts, applications, and recent advances of electrochemical lactate detection platforms. A comparison of hot research for enzymatic and enzyme-free lactate sensors in terms of electrode surface engineering, enzymes and their immobilisation matrices, and several analytical parameters, including linear dynamic range, the limit of detection, sensitivity, and stability, have been discussed. In addition, future perspectives have been highlighted in this review.

Catalytic hydrogenation refers to the (often) metal-mediated addition of dihydrogen (H₂) equivalents to unsaturated compounds to form new element-hydrogen bonds. This conceptually simple reaction is ubiquitous in the production of a vast number of essential chemicals. Despite a growing recognition of the importance of sustainability in manufacturing, the use of fossil-derived hydrogen gas and precious metal catalysts in hydrogenation remains widespread. Electrochemical variants of these processes are an appealing alternative, especially those that can make use of sustainable Brønsted acids, more abundant electrode materials and renewable electricity. In this mini-review, we give a selective overview of electrochemical hydrogenation methodologies for N-heterocycles and some related substrates from the specific perspective of the synthetic chemistry made possible by this increasingly popular approach.

Consecutive development of materials, components, and ultimately, devices does not appear to be a promising strategy in CO₂ electroreduction because maintaining comparability and transferring results between idealized and application-oriented systems proves challenging. A modular cell design and tracking cell conditions via sensors may be a solution. We displayed a strategy to characterize gas diffusion electrode operating regimes in a flow cell with regard to different current density ranges, as well as the impact of the flow gap design. We revealed strong interdependencies between cell components, their functions as well as individual cells when integrated into a stack. Expanding the scope and resolution of experimental data made new information on the change of system parameters in flow cells accessible.

In the first part of this study, double layer (DL) capacitances of plane and porous electrodes were related to electrochemical active surface areas based on electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements. Here, these measured data are described with equivalent circuit models (ECMs), aiming to critically assess the ambiguity, reliability, and pitfalls of the parametrization of physicochemical mechanisms. For microstructures and porous electrodes, the resistive–capacitive contributions of DL in combination with resistively damped currents in pores are discussed to require the complexity of convoluted transmission line ECMs. With these ECMs, the frequency-dependencies of the capacitances of porous electrodes are elucidated. Detailed EIS or CV data-based reconstructions of complex microstructures are discussed as impossible due to the blending of individual structural features and the related loss of information. Microstructures in combination with charge transfer reactions and weakly conducting parts require parameter-rich ECMs for an accurate physicochemical description of all physicochemical mechanisms contributing to the response. Nevertheless, the data of such a complex electrode in the form of an oxidized titanium electrode are fitted by an oversimplistic ECM, showing how easily unphysical parameterizations can be obtained with ECM-based impedance analysis. In summary, trends in how microstructures, charge transfer resistances and oxide layers can influence EIS and CV data are shown, while awareness for the overinterpretation of ECM-analysis is raised.

The increasing impact of industrialization on climate change, primarily due to the emission of greenhouse gases such as carbon dioxide (CO₂), underscores the urgent need for effective strategies for CO₂ fixation and utilization. Electrochemical CO₂ reduction holds promise in this regard, owing to its scalability, energy efficiency, selectivity, and operability under ambient conditions. However, the activation of CO₂ requires suitable electrocatalysts to lower energy barriers. Various electrocatalysts, including metal-based systems and conducting polymers like polyaniline (PANi), have been identified to effectively lower this barrier and enhance CO₂ reduction efficiency via synergistic mechanisms. PANi is particularly notable for its versatile interaction with CO₂, cost-effectiveness, stability, and tunable properties, making it an excellent catalyst option for CO₂ reduction reactions (CO₂RR). Recent advancements in research focus on enhancing PANi conductivity and facilitating electron transfer through metal and metal oxide doping. Leveraging PANi's π–π electron stabilization ensures high conductivity and stability, rendering it suitable for real-time applications. Strategic dopant selection and optimization of Lewis acid-base interactions are crucial for selective CO₂-to-hydrocarbon conversion. Tailored electrode modifications, especially metal/metal oxide-loaded PANi electrodes, outperform conventional approaches, underscoring the importance of catalyst design in advancing CO₂ electroreduction technologies. This review provides a comprehensive analysis of the systematic methodology involved in preparing PANi-modified electrodes and explores the enhancements achieved through the incorporation of metals and metal oxides onto PANi-modified electrodes. It highlights the superior efficiency and selectivity of CO₂RR facilitated by these modified electrodes through profound synergistic approach compared to conventional metal electrodes such as platinum.