ChemElectroChem最新文献

Combining Cu with CO-producing Ag is a promising strategy to improve the selectivity of a CO₂ reduction catalyst. However, the influence of the spatial distribution of the two metals is challenging to investigate. A synthesis route to deposit Cu either on top of a templated porous Ag electrode using sputter coating or inside the porous Ag structure using electrodeposition is presented. The Cu location is confirmed using advanced microscopy images, showing that for the electrodes with electrodeposited Cu, the interfacial area between Cu and Ag is higher. Catalytic testing demonstrates increased C₂₊ production, a lower H₂ selectivity, and higher ethanol-to-ethylene ratio for all bimetallic electrodes than for monometallic Cu or Ag catalysts. This is possibly due to CO spillover from Ag to Cu, electronic interaction between the two metals, or a higher local pH inside the Ag pores. Despite a significant loss of Cu, a high production of ethylene and ethanol is maintained over 6 h of electrolysis. Thus, engineering porous bimetallic electrodes provides an effective strategy to improve the ethylene and ethanol activity and selectivity of Cu-based catalysts.

The peculiar properties of electroactive polymers mark them as protagonists in the bioelectronic research field, with application in point-of-care devices, wearable electronics, neuroscience, cell biology, and more. They have been successfully employed for the design of both sensing and actuating interfaces, which exert complementary functions but benefit from common electrochemical mechanisms unique to these materials. The question is: to what extent sensing and actuating capabilities can be integrated within a single electrochemical transducer? The simultaneous pH detection and pH-controlled release of a model dye are investigated using screen-printed textiles for wearable applications. The transducer is based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and is specifically functionalized to create a two-terminal pH sensor and subsequently loaded with the anionic dye. Simultaneous pH sensing and controlled dye release into the electrolytic solution are demonstrated via electrical and spectrophotometric techniques, while the local release of the dye is confirmed through scanning electrochemical microscopy. The findings confirm that the acquisition of a quantitative analytical signal and the release of the dye do not interfere with each other and can take place simultaneously at the same electrochemical interface. This opens new perspectives for the development of hybrid sensing and drug delivery systems.

The oxygen evolution reaction (OER) is a critical bottleneck in water-splitting technologies. Hence, developing efficient and stable OER electrocatalysts is one of the key parameters to improve this technology. Recently, MXenes such as Ti₃C₂T_x and V₂CT_x have shown promise as OER-enhancing additives when combined with transition metal oxides. However, MXene synthesis requires energy-intensive processes, and the materials are prone to oxidation in various environments, such as air, or during electrochemical reactions. While this oxidation is typically considered detrimental, this study investigates whether partially exfoliated and oxidized V₂CT_x can maintain or even enhance OER performance, potentially simplifying the synthesis requirements for V₂CT_x. In this study, V₂CT_x is intentionally oxidized and incorporated into CuCo-based composites at various loadings. X-ray diffraction and X-ray photoelectron spectroscopy confirm the presence of vanadium oxide species in the partially exfoliated and oxidized V₂CT_x. The electrochemical investigations reveal that the partially exfoliated and oxidized V₂CT_x enhances the OER performance compared to fresh V₂CT_x. These findings suggest that, unlike Ti₃C₂T_x, partially exfoliated and oxidized V₂CT_x retains its functionality in OER catalysis and even outperforms its fresh counterpart, providing a more accessible and efficient platform for water-splitting applications.

LiNi_0.9Mn_0.1O₂ (LNM91) cathode has attracted significant attention in lithium-ion batteries (LIBs) due to its high capacity and low cost. However, its poor electrochemical performance and thermal stability hinder its application in electric vehicles. To overcome these limitations, this study proposes a novel one-step solid-state method for doping Al³⁺ and Mg²⁺ into the Ni and Li sites of LNM91, respectively, by directly mixing hydroxide precursors followed by calcination. Unlike the pristine cathode, which exhibits obvious cracking, the resultant Al/Mg codoped LNM91 maintains its structural integrity well after 100 cycles. The capacity retention significantly increases from 78.5 to 93.0% after 100 cycles at 0.5 C. Mechanistic studies reveal that Al³⁺ stabilizes the oxygen framework through strong AlO bonds, while Mg²⁺ suppresses Li⁺/Ni²⁺ disorder via electrostatic repulsion. Their synergistic effect mitigates the detrimental H2-H3 phase transition and microcrack propagation, thereby bolstering rate capability and cycling performance. These results highlight the significance of Al/Mg codoping as a promising approach for developing high-performance cobalt-free and nickel-rich cathodes for LIBs.

Electrochemical urea synthesis (EUS) from CO₂ and nitrates has recently emerged as a more sustainable alternative to nitrogen fertilizers derived from fossil fuels. Indeed, using captured CO₂ and nitrates from wastewater can offer environmental benefits compared to conventional methods. On the road to EUS technology development, its accurate and reliable quantification is an undeniable cornerstone. As this field is still in its infancy, with very low product concentration and numerous side-products, EUS product quantification is challenging, with reported false positives and negatives. Despite the consensus that at least two methods ought to be used, the selection of the most suitable methods and quantification protocols is an open topic in the scientific community. This work presents a comparative study of the most common methods, highlighting their advantages, limitations, and recent developments, aiming to provide valuable insights to guide the advancement of this emerging field and facilitate the upscaling of sustainable fertilizer production.

Electrochemical water splitting provides a sustainable route for hydrogen production, yet its efficiency is largely constrained by the intrinsically sluggish kinetics of the oxygen evolution reaction (OER) at the anode. Cobalt-based perovskite oxides are promising OER electrocatalysts in alkaline solutions, but their performance strongly depends on crystal structure and electronic configuration. Herein, a phase engineering strategy based on thermal reduction in inert atmospheres, which transforms a hexagonal-structured perovskite with poor OER activity into a cubic-structured perovskite with markedly enhanced OER kinetics, is demonstrated. This cubic phase exhibits a reduced Co valence and increased oxygen vacancy concentration, leading to a 20-fold increase in intrinsic OER activity compared to the hexagonal precursor. Its performance also surpasses that of state-of-the-art perovskites and noble metal- and non-noble metal-based benchmarks. This work highlights phase transformation as a powerful approach to optimize perovskite oxides for efficient OER electrocatalysis.

Artificial enzymatic electrochemistry has emerged as an effective method to extend the catalytic abilities of enzymes, further increasing selectivity and efficiency, while also addressing limitations with stability, substrate scope, and reaction scale. Bioelectrochemical methods are powerful analytical tools to understand and optimize the structure and function of artificial enzymes. However, advancements in this field are hindered by the challenges of practical implementation and insufficient foundational knowledge required for effective integration of biological and electrochemical techniques. This review aims to provide clear examples of artificial enzymatic electrochemistry with an emphasis on the techniques and data that can be obtained for each example. Additionally, we provide an overview of enzymatic electrochemistry experimental design to encourage the incorporation of these techniques into future enzymology research. The review concludes by discussing the outlook and perspective on future opportunities for development.

Although next-generation sodium-ion batteries (SIBs) possess more stable cathode materials than lithium-ion batteries (LIBs), thermal runaway (TR) remains a critical barrier to SIB applications. To resolve this safety paradox, atomic-scale investigations are conducted on the O3-NaNi_1/3Fe_1/3Mn_1/3O₂ (NFM) cathode. Combining accelerating rate calorimetry (ARC) and transmission electron microscopy (TEM), the material-intrinsic resilience is decoupled from cell-level failure mechanisms. The ARC analysis revealed high safety metrics of the NFM/hard carbon pouch cells; specifically, the maximum TR temperature (T₃) stabilizes at ≈310 °C (vs. >800 °C in Ni-rich LIBs) and the TR onset time extends to ≈40 h. As demonstrated in the TEM analysis, the NFM cathode maintains its structural integrity at 310 °C under inert conditions, although post-TR cathodes undergo catastrophic “brush-like” fragmentation with rock-salt/spinel phase transformation. This degradation is mechanistically attributed to reductive attack by electrolyte decomposition products and anode-derived gases (H₂/CO), which overwhelm the inherent stability of the cathode. To guarantee the inherent safety of SIBs, SIB design based on cathode thermochemistry alone must shift to the co-optimization of flame-retardant electrolytes, gas scavengers, and anode passivation.

Galvanic replacement reaction (GRR) is an oxidation–reduction process triggered by an electrochemical potential difference between two metal species, and involves the concerted motion of electrons, atoms, and ions at different times and spatial scales. Despite extensive research, a fundamental question remains unanswered: How can the driving force, that is, the electrochemical potential, be mapped in real time when existing microscopic, optical, and X-ray methods cannot capture it? In this article, the most widely used and fascinating system: silver-gold, in which three silver atoms are replaced by one gold atom, despite silver and gold having almost identical atomic radii, is interrogated. The experimental time-dependent open-circuit potential (OCP(t)) data, as well as phenomenological and mathematical models, are leveraged to describe the dynamics of the GRR. Specifically, modified sigmoidal kinetic functions are proposed based on autocatalytic networks and enzyme cascades performing logic gates, in order to account for the offset and sharpness of the OCP(t) responses at different input concentrations. This allows quantifying, for the first time, the two highly sought-after kinetic parameters of the apparent rate constant and the midpoint growth time. This knowledge can inspire new explorations in GRR-derived syntheses involving different galvanic exchange ratios for new functional nanostructured materials.

M. Paul, A. Grimm, G. Simões Dos Reis, G. Manavalan, S. E S, M. Thyrel, S. Petnikota, “Activated Carbon from Birch Wood as an Electrode Material for Aluminum Batteries and Supercapacitors” ChemElectroChem 2025, 12, e202400549. https://doi.org/10.1002/celc.202400549.

In Paragraph 2 (“Biochar and CBW Preparation”) of the Materials and Methods section, reference [6a] is missing and should be included alongside reference [12]. Additionally, new references should be added as [12c], [12d], [12e], and [12f]. The authors have acknowledged an image compilation error in the subpanels of Figure 3 and have provided the original images to address this issue. They confirm that all experimental results and the corresponding conclusions presented in the paper remain valid and unaffected. The corrected versions of Figure 3c,d are provided below.

Corrected Figure 3c,d;

The scaling of Y-axes provided for better understanding and visualization.

The authors apologize for this error.

References

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