ChemElectroChem最新文献

Electrocatalytic CO reduction (COR) is a promising approach for converting C₁ feedstock into valuable multi-carbon fuels using renewable electricity. At ambient temperature, COR, particularly on Cu-based catalysts, typically produces C₂ chemicals as the dominant products, with long-chain hydrocarbons containing more than five carbon atoms rarely forming. In contrast, Fischer-Tropsch synthesis (FTS), a thermocatalytic process converting CO and H₂, selectively generates long-chain hydrocarbons. In this study, we utilized Ru nanoparticles for electrochemical COR under elevated conditions (423 K and 2.8 MPa). Long-chain products with up to 21 carbon atoms were detected, achieving a Faradaic efficiency of 32 % and a weight selectivity of 65 % for C₅₊ products. We propose an FTS-like pathway for this electrocatalytic process. Unlike thermocatalytic FTS, where adsorbed H atoms form via H₂ dissociation, in this electrocatalytic version, the H atoms are generated through the Volmer reaction from water. Subsequently, the chemisorbed and activated CO species are hydrogenated, forming CH_x intermediates that propagate into long-chain products.

Supercapacitors (SCs) have emerged as promising candidates for efficient and sustainable energy storage devices due to their unique merits, including high power density and long lifespan. However, despite these advantages, SCs face significant challenges related to their relatively low energy density. Current collectors are critical components of SCs, which significantly impacts the efficiency and overall performance by connecting active materials and external devices. However, the reviews on SCs are predominantly focused on electrode active materials or electrolyte materials, with insufficient comprehensive summaries regarding current collectors. This review focuses on the research progress related to current collectors in SCs. Firstly, the article outlines the modification objectives mechanism and inherent nature of SC current collectors. Building on this foundation, the authors further classify the current collector materials towards metallic, carbon-based, polymers and other ones and highlights their modification strategies. Finally, the future development trends and challenges of SCs current collectors are comprehensively discussed.

The Glycerol Electrooxidation Reaction (GEOR) is a promising alternative to oxygen evolution in electrochemical processes like hydrogen production and CO₂ reduction. Although GEOR has attracted increasing attention, its oxidation kinetics in alkaline media are not well understood. In this study, electrochemical characterization and kinetic analysis were conducted using nickel foil as the electrocatalyst. Four galvanostatic conditions (1, 3, 5, and 10 mA cm⁻²) were evaluated to study product distribution. Increasing the current density from 3 to 5 mA cm⁻² led to a fivefold decrease in formate production, indicating a shift in GEOR selectivity within the Oxygen Evolution Reaction (OER) region. At 10 mA cm⁻², formate remained as major product, followed by glycolate and glycerate, while tartronate and oxalate production were significantly inhibited, reducing the total Faradaic Efficiency (FE) by half relative to 5 mA cm⁻². Rate constants showed increased kinetics for glycerate, glycolate, oxalate, and tartronate as current increased, surpassing formate production at 5 mA cm⁻². Spectroelectrochemical measurements revealed the reaction order for GEOR (α_GEOR ~1) and OER (α_OER ~3), showing that GEOR proceeds via a more efficient oxidative pathway, requiring interaction with just one NiOOH species, while OER involves three highly oxidized Ni-species.

Sustainable ammonia synthesis, a key focus in electrochemistry, has seen significant advancements with the emergence of Metal-Organic Frameworks (MOFs). This review provides a comprehensive analysis of the recent strides in MOF-based materials for green ammonia production, reflecting the urgency to develop eco-friendly and energy-efficient chemical commodities. It explores the reaction mechanisms, emphasizing the importance of structure-performance relationships in MOF optimization and the design of MOF-based electrocatalysts, including metal node engineering and hybrid materials. The review also highlights in-situ characterization techniques that are crucial for understanding MOF catalytic activity. It establishes a correlation between MOF features, synthesis methods, and material performance, showcasing their potential in catalysis. Finally, it identifies challenges and future directions for MOFs in green ammonia production, aiming to inspire innovation towards sustainable and economically viable processes.

[The Acknowledgements should be changed from “The authors are grateful for the financial support from the NCN, Poland, UMO-2020/39/B/ST8/02937.” To “The authors are grateful for the financial supports from Project Number 101092189 (Acronim: HEDAsupercap) under the framework of HORIZON-CL4-2022-RESILIENCE-01, funded by European Commission“]

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Active particle materials with high capacity, safety, and abundance, such as Sn and Si-based materials, and nickel-rich layered materials like LiNi_xCo_yMn_1−x−yO₂ (with x≥0.8) are viewed as promising candidates for the evolution of next-generation batteries. However, structural degradation during cycling often limits the application of these active particle materials. Currently, research efforts are focused on developing new characterization techniques to understand the structural degradation mechanisms of active particle materials during the cycle, to improve their performance. This paper reviews advanced single-particle electrochemical and structural characterization techniques and their main findings. These findings included lattice displacement and rotation, microstructure evolution, and reaction kinetics of single-particle during cycling. In addition, we also discuss the potential future applications and developments of single-particle measurement technologies.

The Front Cover shows how the most typical elements present in electrochemistry work together to power and light up the 10th anniversary sign celebrating the last decade of excellent research published in ChemElectroChem. Cover art by Tomáš Belloň (IOCB Prague).

We investigate the flat band voltage (V_FB) of silicon (Si) surfaces functionalized with methyl (Me), 9-anthracene (Anth), 1,8-anthracene (DiAnth; two attachment points), and 9-bianthracene (BiAnth) on n-type and p-type Si substrates. Flat band potential (E_FB, by Mott-Schottky) provided V_FB (or V_BI) dependent on the contacted redox couple (E_Redox). On p-type Si, V_FB increased linearly until a limiting value was reached; similarly, the n-type Si V_FB decreased linearly until it plateaued at more negative potentials. Notably, the slope of V_FB depended on the surface modifier, exhibiting opposite trends for p-type and n-type Si. Curiously, anthracene-functionalized p-Si exhibited an unexpectedly more shallow (and beneficial) slope than -methyl, attributed to the polarizability of the anthracene π electron cloud and a potential drop across the molecular interface. On n-type Si, anthracene-functionalized surfaces displayed a higher slope than -methyl, suggesting a gradual cancellation of the voltage shift effect due to a fixed surface dipole. We also quantified the interfacial potential drop across p-Si–Anth as 275 mV using variable frequency (10 kHz vs 1 kHz) Mott-Schottky analysis. The interfacial potential drop and dipoles that result from molecular functionalization are thus critical design parameters for PEC cells that utilize moderate-potential redox couples or reactions; however, such effects are negligible with redox couples that reside at or beyond the semiconductor band-edge.

Zinc-based batteries are promising for applications in large-scale energy storage and other scenarios due to their high voltage, large theoretical capacity, and abundant reserves. Compared to traditional aqueous electrolytes, deep eutectic solvents (DESs) offer advantages such as wide electrochemical window, good stability, and fewer parasitic reactions. They can effectively regulate the growth morphology of zinc deposits and suppress dendrite formation during zinc deposition/stripping processes. However, there is currently a lack of direct observation for underlying mechanisms of zinc deposition/stripping processes in DESs. In this study, combined with electrochemical methods, in-situ atomic force microscopy (in-situ AFM) has been utilized to investigate the deposition behavior of zinc metal from ZnCl₂ precursor in a deep eutectic solvent composed of choline chloride and ethylene glycol (ethaline). Cyclic voltammetric measurements indicate that zinc deposition is a kinetically controlled process. And in-situ AFM reveals the hexagonal morphology and layered deposition of zinc on highly oriented pyrolytic graphite (HOPG). Our observations benefit the understanding of the kinetics of zinc deposition/stripping in deep eutectic solvent ethaline at a microscopic level.

Strain engineering is an effective approach for modulating the activity of single-atom catalysts, yet the underlying mechanisms are not fully understood. This review focuses on the strain effects on single-atom catalysts, detailing the geometric structure distortion and electronic structure changes of the active sites with different strains. It also discusses the mechanisms behind the modulation of electrocatalytic activity for single-atom catalysts.