Electroanalysis最新文献

Graphene aerogel (GA), known for their loose and porous three-dimensional structures, has been extensively studied and applied in various fields due to their exceptional mechanical strength, thermal conductivity, and electrical properties. However, GA is usually made by freeze-drying method, which is expensive and time-consuming. In this study, a one-pot hydrothermal synthesis method was proposed to successfully fabricate platinum–gold nanoparticle-embedded graphene aerogels (PtAu/3DGA). The resulting PtAu/3DGA material exhibits a highly cross-linked 3D porous structure, a large surface area, and uniformly dispersed metal nanoparticles, which mainly contributes to its outstanding properties. As a methanol fuel cell catalyst, PtAu/3DGA achieves a catalytic activity of 638.3 mA mg⁻¹ and maintains excellent long-term stability. This approach not only improves the high cost and limited catalytic performance of platinum-based alternatives but also offers a scalable and efficient fabrication pathway. The outstanding performance of PtAu/3DGA highlights its potential applications in various fields, including fuel cells, supercapacitors, photocatalysis, and sensors. This work provides a promising strategy for the development of advanced materials with multifunctional applications.

Graphene aerogel (GA), known for their loose and porous three-dimensional structures, has been extensively studied and applied in various fields due to their exceptional mechanical strength, thermal conductivity, and electrical properties. However, GA is usually made by freeze-drying method, which is expensive and time-consuming. In this study, a one-pot hydrothermal synthesis method was proposed to successfully fabricate platinum–gold nanoparticle-embedded graphene aerogels (PtAu/3DGA). The resulting PtAu/3DGA material exhibits a highly cross-linked 3D porous structure, a large surface area, and uniformly dispersed metal nanoparticles, which mainly contributes to its outstanding properties. As a methanol fuel cell catalyst, PtAu/3DGA achieves a catalytic activity of 638.3 mA mg⁻¹ and maintains excellent long-term stability. This approach not only improves the high cost and limited catalytic performance of platinum-based alternatives but also offers a scalable and efficient fabrication pathway. The outstanding performance of PtAu/3DGA highlights its potential applications in various fields, including fuel cells, supercapacitors, photocatalysis, and sensors. This work provides a promising strategy for the development of advanced materials with multifunctional applications.

The use of molybdenum disulfide (MoS₂) as a non-noble metal electrocatalyst for the hydrogen evolution reaction (HER) has gained significant attention due to its affordability and the ease of modifying factors such as voltage, current, duration, and the composition and concentration of the electrolyte solution using electrodeposition techniques. To increase the number of active sites on the surface of MoS₂, fine nanoscale tailoring of the crystalline phase is necessary. This can be accomplished using electrochemical phase formation. In this study, four types of MoS₂ nanoparticles are successfully electrodeposited on copper foil substrates using a mixture of Na₂MoO₄ and Na₂S electrolytes, namely fine nodular MoS₂ (FNMoS₂), small sheet MoS₂ (SSMoS₂), highly porous MoS₂ (HPMoS₂), and low porous MoS₂ (LPMoS₂), with nanoparticles of FNMoS₂, SSMoS₂, HPMoS₂, and LPMoS₂ being produced at potentials of −0.9, −1.0, −1.1, and −1.2, respectively. The electrochemical performance of these nanoparticles on HER is carefully investigated using techniques such as high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and energy dispersive spectroscopy. Linear sweep voltammetry, Tafel plot analysis, and electrochemical impedance spectroscopy are used to study the electrocatalytic performance of HER in a 0.5 M KOH electrolyte. HPMoS₂ electrodeposited at −1.1 V for 200 s had a HER current density of 10 mA cm⁻² at η = −270 mV and a Tafel slope (vs RHE) of 35.8 mV/dec, lower than that of FNMoS₂, SSMoS₂, and LPMoS₂. These results have significant implications for the development of low cost, affordable, and environmentally friendly electrochemical methods of producing hydrogen, and pave the way for further research in this field.

The use of molybdenum disulfide (MoS₂) as a non-noble metal electrocatalyst for the hydrogen evolution reaction (HER) has gained significant attention due to its affordability and the ease of modifying factors such as voltage, current, duration, and the composition and concentration of the electrolyte solution using electrodeposition techniques. To increase the number of active sites on the surface of MoS₂, fine nanoscale tailoring of the crystalline phase is necessary. This can be accomplished using electrochemical phase formation. In this study, four types of MoS₂ nanoparticles are successfully electrodeposited on copper foil substrates using a mixture of Na₂MoO₄ and Na₂S electrolytes, namely fine nodular MoS₂ (FNMoS₂), small sheet MoS₂ (SSMoS₂), highly porous MoS₂ (HPMoS₂), and low porous MoS₂ (LPMoS₂), with nanoparticles of FNMoS₂, SSMoS₂, HPMoS₂, and LPMoS₂ being produced at potentials of −0.9, −1.0, −1.1, and −1.2, respectively. The electrochemical performance of these nanoparticles on HER is carefully investigated using techniques such as high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and energy dispersive spectroscopy. Linear sweep voltammetry, Tafel plot analysis, and electrochemical impedance spectroscopy are used to study the electrocatalytic performance of HER in a 0.5 M KOH electrolyte. HPMoS₂ electrodeposited at −1.1 V for 200 s had a HER current density of 10 mA cm⁻² at η = −270 mV and a Tafel slope (vs RHE) of 35.8 mV/dec, lower than that of FNMoS₂, SSMoS₂, and LPMoS₂. These results have significant implications for the development of low cost, affordable, and environmentally friendly electrochemical methods of producing hydrogen, and pave the way for further research in this field.

Electron transfer is always the spotlight in electrochemistry, especially electrochemical energy storage. However, the current understanding of electron transfer, particularly in heterogeneous systems as explained by Marcus theory, faces challenges in accurately accounting for surface effects, solvent reorganization, and quantum tunneling, which are critical to real-world applications. Here, this review presents a comprehensive analysis of the heterogeneous electron transfer processes within the framework of Marcus theory, focusing on computing approaches using Python and Wolfram Language. The introduction outlines the significance of Marcus theory in explaining electron transfer reactions and sets the stage for the subsequent discussions. In the results and discussions section, the electron distribution in heterogeneous systems is explored, comparing the effects of different formalisms on electron transfer. A detailed comparison of the computational approaches using Python and Mathematica underscores the essential role of programing in tackling complex electron transfer models. These tools offer powerful, complementary capabilities for simulating the nuanced behavior of heterogeneous electron transfer processes, providing researchers with the flexibility and precision necessary to address the limitations of traditional theoretical methods. Finally, the work delves into the law of conservation of energy within the context of Marcus theory, offering a nuanced discussion of its implications for electron transfer studies. This review aims to equip researchers with practical insights and computing tools to enhance their understanding and application of Marcus theory in heterogeneous systems.

Electron transfer is always the spotlight in electrochemistry, especially electrochemical energy storage. However, the current understanding of electron transfer, particularly in heterogeneous systems as explained by Marcus theory, faces challenges in accurately accounting for surface effects, solvent reorganization, and quantum tunneling, which are critical to real-world applications. Here, this review presents a comprehensive analysis of the heterogeneous electron transfer processes within the framework of Marcus theory, focusing on computing approaches using Python and Wolfram Language. The introduction outlines the significance of Marcus theory in explaining electron transfer reactions and sets the stage for the subsequent discussions. In the results and discussions section, the electron distribution in heterogeneous systems is explored, comparing the effects of different formalisms on electron transfer. A detailed comparison of the computational approaches using Python and Mathematica underscores the essential role of programing in tackling complex electron transfer models. These tools offer powerful, complementary capabilities for simulating the nuanced behavior of heterogeneous electron transfer processes, providing researchers with the flexibility and precision necessary to address the limitations of traditional theoretical methods. Finally, the work delves into the law of conservation of energy within the context of Marcus theory, offering a nuanced discussion of its implications for electron transfer studies. This review aims to equip researchers with practical insights and computing tools to enhance their understanding and application of Marcus theory in heterogeneous systems.

Nanoparticles are an indispensable part of our lives. From electronic devices to drug delivery to catalysis and energy storage, nanoparticles have found various important applications. Out of the many synthetic strategies to generate nanoparticles, electrodeposition has stood out due to its cost effectiveness, low time consumption and simplicity. However, traditional electrodeposition techniques have suffered from controlling the size, shape, morphology and microstructure of nanoparticles. Here, we use a technique called nanodroplet-mediated electrodeposition, where nanodroplets carrying the metal salt precursor collide with a negatively-biased electrode. In this work, we use this nanodroplet-mediated electrodeposition technique along with transmission electron microscopy, selected-area electron diffraction and high-angle-annular dark-field scanning transmission electron microscopy to show control over the microstructure of single nanoparticles. Along with that, we use X-ray photoelectron spectroscopy to get mechanistic insights behind the alteration of microstructure observed. Having achieved a control over the microstructure, we show the application by synthesising polycrystalline alloys at room temperature and evaluating the electrocatalytic behavior of the different microstructures towards the hydrogen evolution reaction. This fundamental work of controlling microstructures of single nanoparticles and its applications in alloy synthesis and electrocatalysis opens a new avenue of tuning nanoparticles for various applications.

Nanoparticles are an indispensable part of our lives. From electronic devices to drug delivery to catalysis and energy storage, nanoparticles have found various important applications. Out of the many synthetic strategies to generate nanoparticles, electrodeposition has stood out due to its cost effectiveness, low time consumption and simplicity. However, traditional electrodeposition techniques have suffered from controlling the size, shape, morphology and microstructure of nanoparticles. Here, we use a technique called nanodroplet-mediated electrodeposition, where nanodroplets carrying the metal salt precursor collide with a negatively-biased electrode. In this work, we use this nanodroplet-mediated electrodeposition technique along with transmission electron microscopy, selected-area electron diffraction and high-angle-annular dark-field scanning transmission electron microscopy to show control over the microstructure of single nanoparticles. Along with that, we use X-ray photoelectron spectroscopy to get mechanistic insights behind the alteration of microstructure observed. Having achieved a control over the microstructure, we show the application by synthesising polycrystalline alloys at room temperature and evaluating the electrocatalytic behavior of the different microstructures towards the hydrogen evolution reaction. This fundamental work of controlling microstructures of single nanoparticles and its applications in alloy synthesis and electrocatalysis opens a new avenue of tuning nanoparticles for various applications.

Cover picture provided by Dr. Elena Benito-Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point-of-care diagnostics, wearable sensors, and practical applications.

Cover picture provided by Dr. Elena Benito-Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point-of-care diagnostics, wearable sensors, and practical applications.