ChemElectroChem最新文献

This paper discusses the ethanol oxidation reaction (EOR) on rough Pt electrodes prepared through electrodeposition. EOR on Pt surfaces is typically characterized by a hysteretic cyclic voltammogram in low ethanol concentrations, where anodic current drops due to the formation of surface-poisoning species that hinder further reaction. In this study, we show that Pt electrodes with increased surface roughness (R_f) exhibit a linear EOR response up to 1.4 V versus RHE, in contrast to the hysteretic behavior reported in the literature. We further show that comparable linearity can be induced by increasing the bulk ethanol concentration or decreasing the water content in the electrolyte. These systemic perturbations suggest that enhanced surface roughness promotes higher local coverage of ethanol and its intermediates at the electrode surface, thereby suppressing competitive adsorption of water/OH⁻ species and shifting Pt surface poisoning to more positive potentials. Furthermore, we demonstrate that the antipoisoning effect associated with rough Pt electrode can be amplified by polymer co-electrodeposition, which yields lower current decay rates and higher acetate formation rates compared to rough Pt without polymer. Together, these findings highlight the critical role of catalyst surface roughness in mitigating surface-poisoning processes and promoting efficient electro-oxidation of small organic molecules.

The cover image illustrates a modular workflow for electrode fabrication via 3D printing, electrocatalytic evaluation, and mechanistic analysis of reaction pathways and material properties. The resulting data enable machine-learning approaches to identify optimal reaction and manufacturing conditions and support further process automation. More information can be found in the Review by Dandan Gao and Jennifer Christina Schmidt (DOI: 10.1002/celc.202500397).

A detailed understanding of catalyst degradation under dynamic conditions is essential to develop improved catalysts for the oxygen evolution reaction (OER), the bottleneck for efficient electrochemical water splitting in alkaline media. Perovskite oxides represent an interesting class of OER electrocatalysts, however, the differences in their degradation and repassivation growth rate are not yet fully understood. To address this, epitaxially grown La_0.6Sr_0.4CoO₃ (LSCO), La_0.6Sr_0.4FeO₃ (LSFO), and La_0.6Sr_0.4MnO₃ (LSMO) have been analyzed by in-operando friction force microscopy (FFM) during cyclic voltammetry in 0.1 M KOH. Distinctly different degradation phenomena for these materials were found. Continuous topography and friction force measurements during cycling, and postcatalysis characterization, clearly demonstrated the irreversibility of the degradation process, under dynamic conditions. Specifically, LSMO develops a robust passivation layer accompanied by pronounced roughening. LSFO forms a thin, surface-limited passivating layer with better retention, and LSCO undergoes rapid near-surface conversion with a comparatively soft adlayer. It is demonstrated that the load on the tip has a strong influence on the obtained results, which is used for an attempt to calculate the repassivation rate of the different adlayers. The results elucidate how in-operando FFM can differentiate degradation mechanisms under reaction conditions in alkaline environments and between transition metals in perovskite oxides.

LiNi_0.5Mn_1.5O₄ (LNMO) is a promising high-voltage cathode for next-generation lithium-ion batteries (LIBs) due to its high operating potential, low cost, and cobalt-free composition. However, severe interfacial degradation and structural instability at 4.9 V hinder its practical application. In this work, a uniform niobium-based coating was constructed on LNMO via a scalable sol–gel-assisted solution process. The Nb surface layer provides the mechanical stabilization to maintain the cathode structure and suppress interfacial side reactions. In addition, it enhances Li⁺ diffusion kinetics and is beneficial for the formation of a robust, inorganic-rich cathode–electrolyte interphase. The optimized Nb-LNMO electrode exhibits superior rate capability and cycling stability, retaining 98.3% capacity retention after 200 cycles at 0.3 C in LNMO|Li cells between 3.5–4.9 V, compared to 83.5% for pristine LNMO. This work highlights an effective Nb-based interfacial engineering strategy that reinforces both structural and chemical stability, providing a general approach for designing durable high-voltage cathodes for advanced LIBs.

Membrane electrode assembly (MEA)-based CO₂ electrolyzers enable high-rate electrochemical CO₂ reduction reaction (CO₂RR) with industrially relevant current densities, but their durability is often limited by salt precipitation and electrode flooding. This review aims to elucidate the mechanisms of salt formation in zero-gap MEA systems, emphasizing the coupled roles of ionic transport, water flux, and carbonate chemistry. Recent advances in mitigating salt precipitation are summarized through (i) system-component engineering, including hydrophobic electrode design, electrolyte optimization, flow-field modification, and membrane permselectivity control, and (ii) operational strategies such as elevating temperature, periodic flushing, and pulsed electrolysis. Furthermore, the emerging potential of acidic MEA systems that suppress carbonate crossovers is highlighted while discussing their concurrent challenges in water management. Finally, future directions toward integrated material–system–operation codesign are outlined to achieve stable, scalable, and CO₂-efficient electrolyzer. This work provides a framework for understanding and controlling salt precipitation, guiding the development of next-generation MEA-based CO₂ electroreduction technologies.

The superphosphate thin film of Fe₃(NH₄)H₈(PO₄)₆.6H₂O is electrodeposited using a concentrated solution of 2 M phosphoric acid and a Mohr's salt precursor (Fe(NH₄)₂(SO₄)₂.6H₂O). The electrochemical oxidation of the Fe(H₂PO₄)⁺ complex present in the medium is monitored by cyclic voltammetry and shows that the deposition results from a combination of different phenomena such as diffusion and adsorption. The electrodeposition is carried out using the chronoamperometric method at a potential of 0.6 V/saturated calomel electrode. The resulting material is studied by X-ray diffraction and has a hexagonal structure corresponding to the P31c space group, with lattice parameters of a = 9.15 Å and c = 16.86 Å; its morphology is studied by scanning electron microscopy combined with energy dispersive X-ray spectroscopy, which shows a rod structure and confirms the presence of its constituent elements. Fourier transform infrared spectroscopy reveals lattice vibration bands, associated with (PO₄)₃⁻ ions and water molecules. Meanwhile, thermogravimetric analysis and differential scanning calorimetry indicate water loss at around 187 °C.

Combining transition metal oxides with polarity and 3D porous carbon materials to leverage their synergistic effects is an effective strategy for addressing the challenges in lithium–sulfur batteries. In this work, in order to accelerate catalytic conversion of polysulfides, the co-growth strategy is proposed, in which transition metal spinel oxide NiCo₂O₄ (NCO) is anchored on the surface of the reduced graphene oxide aerogel (rGA) to form hierarchical structure NCO@rGA-13. The results show that the specific surface area of NCO@rGA-13 is 226 m²g⁻¹, which is higher than rGA (133 m²g⁻¹), indicating that the addition of NCO can increase the reactive sites and adsorption sites. Besides, it has been found that NCO@rGA-13/S cathode delivers an initial discharge specific capacity of 1112 mAh g⁻¹ at 1 C, keeping a capacity of 722 mAh g⁻¹ after 500 cycles and a low capacity fading rate of 0.07% per cycle. In situ ultraviolet-visible spectroscopy confirms that the concentration of $$ for NCO@rGA-13 is higher than rGA, indicating that NCO@rGA-13 can accelerate the conversion of polysulfides. Therefore, this work presents an efficient strategy to simultaneously achieve dual adsorption and catalytic conversion of polysulfides, which is conducive to facilitating the industrialization of LSBs.

Electrochemical CO₂ reduction is a promising technology for captured carbon utilization, but its economic viability is limited by the oxygen produced at the anode. Replacing water oxidation with the oxidation of organic substrates can offset the CO₂ reduction costs. In particular, the selective oxidation of ethylene glycol (EG) to glycolic acid (GA) can add value to the process. Here, we study the compatibility of the electrochemical ethylene glycol oxidation over palladium and CO₂ reduction. To do this, we synthesized a layered PdAg@NF_L electrode by the electrodeposition method. Voltammetry experiments, optical microscopy, and X-ray diffraction analysis confirmed the formation of the layered electrode. Electrolysis runs at 10 mA/cm²_{geo anode} studying {EGO} and {EGO-CO₂R} systems showed excellent selectivity toward glycolate (85–100% Faraday yield). Only trace amounts of oxalate and formate were observed in the anolyte of both systems. CO₂ reduction was performed using a 60% Au@Vulcan gas diffusion electrode. The cathodic products were CO, formic acid, and H₂, with the latter being the majority product.

This work presents analytical solutions for the impedance of a relaxation process whose time-constant distribution follows 1) a Cauchy-distribution or 2) a Gauss-distribution. Both functions are commonly used as basis for the numerical reconstruction of the time-constant distribution from experimental impedance data (i.e., the opposite way). Herein it is, however, demonstrated that neither a single Cauchy, nor a single Gauss function, can resemble common experimental features of impedance—especially the nonperpendicular traversal in the Nyquist representation, which is oftentimes seen for experimental data. While both functions will (depending on their width) qualitatively introduce a ‘depressed semi-circle’ in the Nyquist plot, a Gaussian relaxation function leads to a perpendicular intercept with the abscissa and a Cauchy-type relaxation function to an angle of zero degree at high and low frequencies.

Electrochemical CO₂ reduction is a promising approach for a sustainable economy, as it converts CO₂ into valuable products. However, converting CO₂ into multicarbon products specifically, toward acetate as the major product, is challenging due to high energy barriers and low CO* coverage on the catalyst surface. This leads to the primary products being ethylene and ethanol instead. While electrochemical approaches for converting CO to acetate are gaining attention, accomplishing this directly through CO₂ reduction remains a substantial challenge. This mini review summarizes recent advancements in catalyst design and experimental strategies to convert CO₂ into acetate. We discuss various strategies, innovations in catalyst design, and electrochemical setups to enhance selectivity and efficiencies.