ChemElectroChem最新文献

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

[12c] G. Li, A. Lakunkov, N. Boulanger, O. A. Lazar, Oana, M. Enachescu, A. Grimm, A. V. Talyzin, “Activated carbons with extremely high surface area produced from cones, bark and wood using the same procedure”, RSC Advances, 2023, 13, 14543–14553, https://doi.org/10.1039/D3RA00820G.

[12d] A. Nordenström, N. Boulanger, A. Lakunkov, G. Li, R. Mysyk, G. Bracciale, P. Bondavalli, A. V. Talyzin, “High-surface-area activated carbon from pine cones for semi-industrial spray deposition of supercapacitor electrodes”, Nanoscale Advances, 2022, 4, 4689–4700, https://doi.org/10.1039/D2NA00362G.

[12e] N. Boulanger, V. Skrypnychuk, A. Nordenström, G. Moreno-Fernández, M. Granados-Moreno, D. Carriazo, R. Mysyk, G. Bracciale, P. Bondavalli, A. V. Talyzin, “Spray Deposition of Supercapacitor Electrodes using Environmentally Friendly Aqueous Activated Graphene and Activated Carbon Dispersions for Industrial Implementation”, ChemElectroChem 2021, 8, 1349–1361, https://doi.org/10.1002/celc.202100235.

[12f] A. Lakunkov, V. Skrypnychuk, A. Nordenström, E. A. Shilayeva, M. Korobov, M. Prodana, M. Enachescu, S. H. Larsson, A. V. Talyzin, “Activated graphene as a material for supercapacitor electrodes: effects of surface area, pore size distribution and hydrophilicity”, Physical Chemistry Chemical Physics, 2019, 21, 17901–17912, https://doi.org/10.1039/C9CP03327K.

As a key parameter, pH has received a lot of attention from the sensing perspective. New materials and technologies are being used to produce state of the art devices capable of tracking it. However, most generic sensors lack the applicability that certain applications require. In this article, 3D printing technology is used to its full potential to produce electrodes, which are modified into pH sensors and reference electrodes, with shapre-driven additional functionality for monitoring ammonia recovery in a bioreactor. The 3D-printed electrodes are modified with a layer of iridium oxide to be turned into pH sensitive devices. Their characterization showed their characteristic super-Nernstian response (−77 ± 0.2 mV pH⁻¹), high reproducibility (RSD < 5%) between sensors and repeatability (RSD < 2%) between measurements. Moreover, the sensors are stable for at least 20 days and tunable in length. All of this results in the sensors being built into a functional shape and tested to monitor the performance of an ammonia-producing bioelectrochemical reactor.

Developing efficient, acid-stable, and noncritical oxygen evolution reaction (OER) catalysts is crucial for the advancement of multiple renewable energy technologies. In this work, the design and synthesis of manganese oxide-based catalysts (MnO_x) are investigated, combined with varying ratios of gold nanowires (Au NWs)—both considered noncritical raw materials—to fabricate composite materials for use in acidic OER. The experimental findings indicate that approximately two-thirds of MnO_x within the catalyst layer is fully utilized when Mn is present at an atomic ratio of 5:1 to Au. This is primarily attributed to the incorporation of Au NWs, which markedly improves the conductivity of the catalyst layer. Cyclic voltammetry analyses suggest that in the composite with an atomic ratio of 5 Mn to 1 Au, Mn³⁺ remains persistently present on the surface of MnO_x throughout testing. This not only maintains the enhanced OER activity, but also significantly reduces Mn dissolution. Moreover, gas diffusion electrode measurements demonstrate that the “5Mn + 1Au” composite can achieve a current density of 1000 mA cm⁻². This observation reinforces the concept of employing composite electrocatalysts derived from noncritical raw materials and highlights their potential for catalyzing the OER in acidic environments.

Hard carbon is commonly used as negative electrode in sodium-ion-batteries (SIBs). Another type of disordered carbon, soft carbon (SC, also known as graphitizable carbon), is considered as unsuitable for SIB applications, due to sodium storage at higher potentials and with lower capacities. However, SCs exhibit structural flexibility, enabling graphene rearrangements at higher temperatures. This property was utilized in the current study to introduce closed porosity in carbon black (CB) and to alter the nanostructure to achieve a beneficial sodium storage mechanism for higher energy densities. For that, CB is CO₂ activated at 900 °C and different holding times to generate different porosities. High-temperature treatment (HTT) at 1500 °C induces the graphitization process and closure of pore entrances. N₂ and CO₂ physisorption confirm the pore generation after activation and reduced porosity after HTT. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy show no other structural alteration compared to nontreated CB. Galvanostatic charge-discharge experiments reveal an extension of the low-voltage plateau, showing a “hard carbon like” storage in correlation with the micropore volume introduced. These findings add to the knowledge of the sodium storage mechanism and showcase the possible need for revising the common carbon classification in the context of SIB research.

The Front Cover article presents a wearable paper-based biofuel cell that enables self-powered monitoring of sweat lactate levels via a low-power wireless transmission device. More information can be found in the Research Article by Isao Shitanda, Noya Loew, and co-workers (DOI: 10.1002/celc.202500222).

With the rising prevalence of metabolic diseases, infections, and mental health disorders, there is a growing demand for noninvasive diagnostic tools that enable early detection and continuous health monitoring. In this context, exhaled breath biomarkers provide insight into physiological and pathological processes. Electrochemical breath sensors (EBSs) have emerged as a promising platform for rapid, real-time, and cost-effective disease tracking via the detection of volatile breath biomarkers, such as NH₃, NO, and CO₂. Recent advancements in electrode materials, biological recognition elements, and sensor architectures—spanning nanomaterials, enzymes, aptamers, and molecularly imprinted polymers—have enhanced the analytical performance of EBSs. Nonetheless, challenges remain in achieving biologically relevant detection ranges, selectivity in complex breath matrices, and long-term environmental stability. This perspective article provides a critical overview of recent innovations and enduring limitations in EBS development. Beyond their role in monitoring physiological diseases, we highlight the emerging potential of EBSs for mental health assessment through the detection of gut-derived metabolites in exhaled breath, such as short-chain fatty acids, H₂S, and ammonia, as indicators of gut–brain axis activity. The EBS-based, noninvasive, real-time measurement of these metabolites represents a transformative and underexplored approach for the diagnosis and treatment of psychiatric disorders.