Efficient Electrode Material Research Articles

Influence of anodic treatment of nickel in deep eutectic solvents on electrocatalytic activity in oxygen evolution and urea oxidation reactions

The influence of anodic potentiostatic treatment of nickel surface in deep eutectic solvents, ethaline and reline (eutectic mixtures of choline chloride with ethylene glycol and urea, respectively), on the electrocatalytic activity in the electrochemical reactions of oxygen evolution and urea oxidation in an aqueous alkaline medium (1 M NaOH) was investigated for the first time. It was shown that, depending on the chosen treatment potential and the nature of the eutectic solvent used, a significant increase in the rate of the studied processes was observed. Specifically, after anodic treatment of nickel under certain conditions, the polarization of the oxygen evolution reaction at a current density of 0.1 A/cm2 could be reduced by approximately 150–200 mV, and the maximum current density of urea oxidation could be increased by an order of magnitude (from 0.012 A/cm2 to 0.131 A/cm2 at a urea concentration of 0.33 mol/dm3 in alkaline solution). The observed increase in electrocatalytic activity after anodic treatment of nickel in deep eutectic solvents is likely related to changes in surface morphology patterns and the nature and concentration of relevant electroactive sites on the electrode surface. The results obtained in this work can be used for the development of highly efficient electrode materials for green hydrogen energy.

Hydrothermal synthesis of (NiFe/NiCo)S@NF bilayer electrocatalyst for efficient hydrogen evolution reaction

Hydrogen is widely recognized as a renewable and clean energy source that has the potential to reduce dependence on fossil fuels. However, it is crucial to develop efficient, affordable, and sustainable electrocatalysts for hydrogen production through water splitting. To tackle this challenge, a bilayer Ni–Fe–Co-based sulfide was hydrothermally grown on Ni foam to boost the hydrogen evolution reaction (HER). SEM images revealed the micro-sized NiFe sheets decorated with NiCo nanosheets on the surface. The (NiFe/NiCo)S@NF electrocatalyst demonstrated outstanding performance towards HER in a 1 M KOH solution, where only a low overpotential of 185 mV vs. RHE was required at −10 mA/cm2, being considerably lower than those for NiFeS@NF (230 mV), NiCoS@NF (229 mV), NiFe@NF (237 mV) and NiCo@NF (256 mV) electrodes. This improvement could be attributed to the synergistic effect between constituents, the presence of Ni3S2 and NiCo2S4 phases, and the higher exposed area provided by the 3D nano/micro structure of the (NiFe/NiCo)S@NF electrocatalyst. Furthermore, this electrocatalyst exhibited the lowest Tafel slope of 76 mV/dec compared to NiFeS@NF (92 mV/dec), NiCoS@NF (87 mV/dec), NiFe@NF (89 mV/dec), and NiCo@NF (102 mV/dec), indicating its faster HER kinetics. Finally, in a two-electrode system of (NiFe/NiCo)S@NF||(NiFe/NiCo)S@NF, a low voltage of 1.58 V was required to obtain a current density of 10 mA/cm2 and the synthesized electrocatalyst had excellent stability over 12 h electrolysis. The achieved results proved that the (NiFe/NiCo)S electrocatalyst has great potential as a highly efficient electrode material for alkaline HER.

A Supramolecular Organic Framework‐Mediated Electrochemical Strategy Achieves Highly Selective and Continuous Uranium Extraction

AbstractThe integration of selectivity and electron transfer ability remains a primary challenge in developing electrode materials for uranium electroextraction. Herein, a phenanthroline‐based supramolecular organic framework (MPSOF) is elaborately constructed as a pioneering cathode material through the hydrogen bond‐driven self‐assembly of melamine and 1,10‐phenanthroline 2,9‐dicarboxylic acid (PDA) for selective and continuous electrochemical uranium extraction (EUE). PDA moieties selectively capture UO22+, while the hydrogen bond‐supporting frameworks provide an efficient electron transfer channel for the redox of UO22+. These structural features enable the rapid formation and spontaneous shedding of uranium precipitate from MPSOF, allowing for the regeneration of the selective adsorption sites. As a result, MPSOF‐mediated EUE exhibits a high extraction capacity of 7311 mg U g−1 at a low voltage of −3.5 V but does not reach equilibrium. Cyclic EUE is employed to uranium extraction from simulated high‐salt radioactive effluents and attains high selectivity for uranium. The electroextraction mechanism is confirmed, wherein uranium species transform into (UO2)O2·4H2O. This work not only provides an efficient electrode material for uranium electroextraction, but also presents a novel electrochemical strategy for separation and adsorption of other radionuclides and contaminant ions.

Nitrogen-enriched nanoporous polytriazine as efficient electrode material for high-performance supercapacitor application in non-aqueous medium with high cyclic stability

Nitrogen-enriched nanoporous polytriazine (NENP) synthesized by conventional heating method possesses a high specific surface area (SABET) of 966 m2 g−1, controlled pore size distribution (1.6, 5, and 8.3 nm) and total pore volume of 2.73 cm3 g−1. The synthesized specimen was utilized as an electrode material for supercapacitor (SC) application in non-aqueous media. The electrodes of NENP were fabricated by two approaches viz., conventional binder-based method and a binder-free electrophoretic deposition (EPD) approach. In case of electrode fabrication by controlled EPD process, the mass of 0.58 mg was obtained as the optimized mass achieved at pH = 2, deposition voltage = 20 V and deposition time = 6 min. The optimized electrodes and tetraethylammonium tetrafluoroborate in adiponitrile (TEA-BF4/ADP) non-aqueous electrolyte were used to fabricate symmetric supercapacitor devices (SC). The SC device, with EPD- based binder-free electrodes, exhibited higher specific capacitance (Csp = 84 F g−1), energy density (Esp = 118.8 Wh kg−1) and power density (Psp = 17 kW kg−1) compared to SC device (49 F g−1, 68.8 Wh kg−1, and 11 kW kg−1 at 0.8 A g−1) fabricated using electrode made from the binder based method. To enhance the SC performance, KI was added as a redox additive to the non-aqueous electrolyte (TEA-BF4/ADP). The SC device, with NENP binder-free electrodes and redox-active nonaqueous electrolyte (TEA-BF4/ADP/KI), achieved the highest Csp, Esp, and Psp (112 F g−1, 150.5 Wh kg−1, and 27 kW kg−1) and demonstrated high cyclic stability (~80.2 % initial capacitance retention after 30,000 cycles, at 5 A g−1).

Morphology controlled synthesis of MnCo2S4 nanoflower structures for different metal precursors used for energy storage applications

Supercapacitors have been considered efficient energy storage devices because of their promising electrochemical charge storage capabilities. Nevertheless, an efficient electrode material is needed to fulfill the demands of current supercapacitor technology. This study examines the influence of various metal precursors (acetate (A), nitrate (N), and chloride (C)) on the morphology-dependent supercapacitor performance of MnCo2S4 (MCS) fabricated on nickel foam using an in situ hydrothermal method to obtain an optimized electrode material. The flower-like porous morphology of MCS N provides a maximum number of electrochemically active sites to the electrode material, enhancing the attainable surface area of the electrolyte upon increasing the electrochemical performance. The electrode material MnCo2S4 derived from a nitrate precursor exhibits higher specific capacity compared to MCS A and MCS C, reaching 2367C g−1 at 1 A g−1 and demonstrating 90 % cycles stability over 5000 cyclings. Likewise, an asymmetric supercapacitor (ASC) is developed by coupling activated carbon (negative electrode) with MnCo2S4 (positive electrode), yielding notable performance, such as 217 F g−1 capacitance at 1 A g−1, along with high energy and power densities of 63.3 Wh/kg and 6000 W kg−1, correspondingly. These outcomes emphasize the morphology-dependent behavior of MnCo2S4 in advancing supercapacitor design.

Encapsulating Mn-Fe prussian blue analog nanocuboids into the graphene framework towards fast and durable sodium storage

The exploration of high-performance sodium-ion hosts is an important issue in the field of advanced energy storage and conversions. Herein, MnFe PBA/rGO composite was prepared by simple coprecipitation and in situ synthesis, and realized the fast kinetics and superior stability for sodium storage. The rGO nanosheets were introduced as the framework to encapsulate the MnFe PBA nanocuboids with uniform particle size and well-defined configuration to further enhance their electrical conductivity and electrochemical properties. The prepared MnFe PBA/rGO composite exhibits superior charge/discharge properties than the pristine MnFe PBA nanocuboids, which show a capacity enhancement of over 30%. In addition, the PBA/rGO composite exhibits excellent cycling stability, which retains 80% of the capacity after 1000 cycles at a high rate of 1 A/g. The electrochemical impedance spectroscopy (EIS) results further demonstrate the low resistance, high durability, and ultrahigh stability of the MnFe PBA/rGO composite during high-rate long-term cycling. Therefore, this work not only provides a high-performance sodium host but also gives a new clue to the design and construction of highly efficient electrode materials for advanced electrochemical systems.

Fabrication of Co1.5Ni1.5S4 and Prussian blue analogues composites with yolk-shell heterostructures as cathode and biomass derived carbon as anode for asymmetric supercapacitors

As highly efficient electrode materials for supercapacitors, the clean production of transition metal sulfide and biomass-derived carbon played an important role in promoting the practical process. In this work, Prussian blue analogues were grown in situ on glycerate precursors through a simple ion-exchange process, followed by sulfidation to obtain the Co1.5Ni1.5S4 and Prussian blue analogues composite microspheres with yolk-shell structures. Thanks to the unique micro-nano structure and multi-element synergy, composites exhibited excellent specific capacitance (up to 2388.7 F g−1 at 1 A g−1), rate performance (55.0 % capacitance retention at 30 A g−1), and cycling stability (capacitance maintained at 81.5 % after 5000 cycles). In addition, Nitrogen-doped sunflower seed shell derived carbon, prepared by two pyrolysis and salt-activation processes, could attain a specific capacitance of 347.1 F g−1 at 1 A g−1 and an almost undiminished capacity of 5000 cycles. With Co1.5Ni1.5S4 and Prussian blue analogues composites as cathode and derived carbon as anode, the assembled hybrid supercapacitor exhibited an eminent energy density of 82.2 Wh kg−1 (at a power density of 904.9 W kg−1) and stable cycling characteristics (only 16.7 % loss of capacitance after 10,000 cycles). This work provided a feasible scheme for the structure regulation of sulfides and the defect construction of porous carbon.

High Capacitance Porous Ruthenium Nitride Films with High Rate Capability for Micro-Supercapacitors.

The demand for high-performance energy storage devices to power Internet of Things applications has driven intensive research on micro-supercapacitors (MSCs). In this study, RuN films made by magnetron sputtering as an efficient electrode material for MSCs are investigated. The sputtering parameters are carefully studied in order to maximize film porosity while maintaining high electrical conductivity, enabling a fast charging process. Using a combination of advanced techniques, the relationships among the morphology, structure, and electrochemical properties of the RuN films are investigated. The films are shown to have a complex structure containing a mixture of crystallized Ru and RuN phases with an amorphous oxide layer. The combination of high electrical conductivity and pseudocapacitive charge storage properties enabled a 16µm-thick RuN film to achieve a capacitance value of 0.8Fcm-2 in 1m KOH with ultra-high rate capability.

Co-doping mechanism of biomass-derived nitrogen-boron porous carbon and its applications in energy storage and environmental purification

In this paper, we aim to design and synthesize a low-cost, multifunctional and efficient electrode and adsorbent material (nitrogen doped and nitrogen-boron co-doped) by combinatorial doping of heteroatoms using cherry blossoms (Prunus yedoensis) as biomass feedstock. The differences in morphology and structure of the two materials due to the doping of boron atoms were analyzed. Among them, the nitrogen-boron co-doped porous carbon NBKCC had a hierarchical porous structure with a shape similar to that of carbon microspheres and a specific surface area as high as 1184 m2/g. In the three-electrode system, the specific capacitance of the assembled electrodes was 337.5 F/g (current density: 0.5 A/g). In the NBKCC symmetric capacitor test, the energy density could reach 15.1 Wh/kg at a power density of 420.5 W/kg. After 10,000 charge/discharge cycles, the capacitance retention was 96.98 % (5 A/g), which showed good stability. In addition, we evaluated the adsorption capacity of carbon microspheres for malachite green, rhodamine B, and methylene blue. Among them, the maximum adsorption of malachite green in a single system was 572.4 mg/g. Based on this, we demonstrated the feasibility and preparation of porous carbon materials by combinatorial doping with heteroatoms using biomass waste cherry blossoms as carbon substrates.

Facile controllable sequential electrochemical in-situ synthesis of Fe3O4/PPY hybrid electrode for supercapacitor

In this work, a facile sequential electrochemical synthesis strategy is employed for the precisely controlled in situ polymerization of pyrrole on an iron oxide substrate in the oxalic acid system. The use of porous iron oxide as a template allows for the modification of polypyrrole to create a large conductive network while preserving the integrity of the substrate. This process improves the poor conductivity of conventional metal oxides, allowing for the synthesis of a Fe3O4/PPY hybrid electrode material. The experiments elucidated the mechanism of pyrrole surface morphology coupled with the deposition amount threshold affecting the electrode performance. This was achieved by elucidating the regulation laws of key deposition process parameters (pyrrole monomer concentration, scanning rate, and number of cycles) on the diffusion and oxidation behaviors of pyrrole during the continuous polymerization process. Furthermore, the electrochemical behaviors of the Fe3O4/PPY hybrid electrode were better resolved. The results demonstrate that the deposition amount of PPY on the Fe3O4/PPY hybrid electrode material is within the optimized threshold (1 × 10−6∼3 × 10−6 g), exhibiting a regular and uniform surface morphology with no agglomeration, which indicates a competitive specific capacitance (215.12 mF cm−2 at 1.1 mA cm−2). This strategy of structure-modulated synergistic functional hybridization offers a new approach for designing efficient binder-free hybridized electrode materials.

Fabrication of porous Ni–Co LDH@rGO nanocomposites as efficient electrode materials for asymmetric supercapacitor

Fabrication of porous Ni–Co LDH@rGO nanocomposites as efficient electrode materials for asymmetric supercapacitor

Molybdenum Sulfide Nanoflowers as Electrodes for Efficient and Scalable Lithium-Ion Capacitors.

Hybrid supercapacitors (HSCs) bridge the unique advantages of batteries and capacitors and are considered promising energy storage devices for hybrid vehicles and other electronic gadgets. Lithium-ion capacitors (LICs) have attained particular interest due to their higher energy and power density than traditional supercapacitor devices. The limited voltage window and the deterioration of anode materials upsurged the demand for efficient and stable electrode materials. Two-dimensional (2D) molybdenum sulfide (MoS2) is a promising candidate for developing efficient and durable LICs due to its wide lithiation potential and unique layer structure, enhancing charge storage efficiency. Modifying the extrinsic features, such as the dimensions and shape at the nanoscale, serves as a potential path to overcome the sluggish kinetics observed in the LICs. Herein, the MoS2 nanoflowers have been synthesized through a hydrothermal route. The developed LIC exhibited a specific capacitance of 202.4 F g-1 at 0.25 A g-1 and capacitance retention of >90 % over 5,000 cycles. Using an ether electrolyte improved the voltage window (2.0 V) and enhanced the stability performance. The ex-situ material characterization after the stability test reveals that the storage mechanism in MoS2-LICs is not diffusion-controlled. Instead, the fast surface redox reactions, especially intercalation/deintercalation of ions, are more prominent for charge storage.

Interfacial Interaction in MeOx/MWNTs (Me-Cu, Ni) Nanostructures as Efficient Electrode Materials for High-Performance Supercapacitors.

Due to their unique physical and chemical properties, complex nanostructures based on carbon nanotubes and transition metal oxides are considered promising electrode materials for the fabrication of high-performance supercapacitors with a fast charge rate, high power density, and long cycle life. The crucial role in determining their efficiency is played by the properties of the interface in such nanostructures, among them, the type of chemical bonds between their components. The complementary theoretical and experimental methods, including dispersion-corrected density functional theory (DFT-D3) within GGA-PBE approximation, scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, X-ray photoelectron, and X-ray absorption spectroscopies, were applied in the present work for the comprehensive investigation of surface morphology, structure, and electronic properties in CuOx/MWCNTs and NiOx/MWCNTs. As a result, the type of interfacial interaction and its correlation with electrochemical characteristics were determined. It was found that the presence of both Ni-O-C and Ni-C bonds can increase the contact between NiO and MWCNTs, and, through this, promote electron transfer between NiO and MWCNTs. For NiOx/MWCNTs, better electrochemical characteristics were observed than for CuOx/MWCNTs, in which the interfacial interaction is determined only by bonding through Cu-O-C bonds. The electrochemical properties of CuOx/MWCNTs and NiOx/MWCNTs were studied to demonstrate the effect of interfacial interaction on their efficiency as electrode materials for supercapacitor applications.

Coal-based carbon nanosheets contained carbon microfibers modified with grown carbon nanotubes as efficient air electrode material for rechargeable zinc-air batteries

Coal-based oxygen electrocatalysts hold immense promise for cost-effective applications in rechargeable Zn-air batteries (ZABs) and the value-added, clean utilization of traditional coal resources. Herein, an electrospun membrane electrode comprising coal-derived carbon nanosheets and directly grown carbon nanotubes (CNS/CMF@CNT) was successfully synthesized. The hierarchical porous structure of the electrode, composed of multiple components, significantly facilitates mass and ion transportation, resulting in exceptional electrochemical performance. Employing Fe as the catalyst for CNT growth, the CNS/CMF@CNT electrode exhibits a remarkable onset potential of 0.96 V and a half-wave potential of 0.87 V in the oxygen reduction reaction (ORR). In-situ surface-enhanced Raman spectroscopy reveals that hydroxyl radical desorption on the surface of CNS/CMF@CNT(Fe) is the rate-determining step of the ORR. Notably, the aqueous ZAB featuring the CNS/CMF@CNT(Fe) electrode achieved a peak power density of 216.0 mW cm−2 at a current density of 414 mA cm−2 and maintained a voltage efficiency of 65.1 % after 2000 charge/discharge cycles at 5 mA cm−2. Furthermore, the all-solid-state ZAB incorporating this electrode displayed an open-circuit voltage of 1.43 V, a peak power density of 70.1 mW cm−2 at a current density of 110 mA cm−2, and a voltage efficiency of 66.5 % after 150 charge/discharge cycles. The utilization of abundant coal as the raw material for electrode fabrication not only brings conceivable economic benefits in ZAB construction, but also commendably advances the effective application of traditional coal resources in a more sustainable manner.

PDDA-modified nanoflower-like BiOCl/MXene hybrid electrode for efficient capacitive deionization dichlorination

Currently, chloride ions in industrial water limits its reuse when extending the circulating water cycle. Therefore, it is necessary to remove Cl− to ensure its effective reuse. Considering the development of new materials for efficient electrochemical chloride removal is a key issue limiting the development of capacitive deionization technology for chlorine removal. In this study, BiOCl was grown in situ on the surface of V-MXene, and then a nanoflower-like BiOCl/MXene composite was synthesized by utilizing the properties of MXene as a structure-directing agent to modulate the morphology, which exhibits superior pore structure and specific capacitance. The poly (diallyl dimethylammonium) (PDDA) modification improved the materials’ specific capacitance and reduced energy consumption for dichlorination. The optimal BMP-10 exhibited superior performance for dichlorination, the maximum dichlorination capacity and rate were 161.64 mg g−1 and 2.20 mg g−1 min−1. We found that MXene has excellent properties for exfoliation and morphology modulation of layered materials. Additionally, the electrical properties have an important influence on the electrochemical removal of chloride ions. Here we successfully synthesized an efficient electrode material with unique morphological structure for CDI dichlorination and provided ideas for structure-directing agents and electrical modulation in material design for electrochemical dichlorination.

Ti3AlC2 MAX Phase Modified Screen-Printed Electrode for the Fabrication of Hydrazine Sensor.

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1-50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology.

Improved electrochemical performance of hydrothermally synthesized Zn-Ni-S/rGO nanocomposite as an electrode for supercapacitor application

This present work reports on the hydrothermal synthesis of zinc-nickel sulfide with reduced graphene oxide (Zn-Ni-S/rGO) nanocomposite for supercapacitor applications. The synthesized samples are evaluated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), and high-resolution scanning transmission electron microscopy (HR-TEM), which are employed to examine the structure, morphology, and chemical composition of the Zn-Ni-S/rGO nanocomposite. The XRD results indicates formation of high crystalline Zn-Ni-S/ rGO nanocomposites. FE-SEM equipped with an EDX spectrum, illustrates a spherical morphology of Zn-Ni-S combined with a thin layer of rGO in the form of composite nature. Furthermore, elemental composition of Zinc, Nickel, Sulfur and Carbon presence in the EDS spectra further supports the formation of Zn-Ni-S/rGO nanocomposite. The electrochemcial properties of ZnS and Zn-Ni-S/rGO nanocomposite are studied through cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. High specific capacitance of 284 F/g is obtained at 11 mA g−1 current density. The Zn-Ni-S/rGO nanocomposite demonstrates high capacitance retention of 96 % over 3,000 cycles. The potential application of the Zn-Ni-S/rGO nanocomposite as an efficient electrode material for pseudocapacitors is supported by its favourable performance.

Enhanced electrochemical performance of La2S3/N-rGO/PANI nanocomposites as an efficient electrode material for supercapacitor applications

Enhanced electrochemical performance of La2S3/N-rGO/PANI nanocomposites as an efficient electrode material for supercapacitor applications

Green and sustainable use of macadamia nuts as support material in Pt-based direct methanol fuel cells

The successful commercialization of direct methanol fuel cells (DMFCs) is hindered by inadequate methanol oxidation activity and anode catalyst longevity. Efficient and cost-effective electrode materials are imperative in the widespread use of DMFCs. While Platinum (Pt) remains the primary component of anodic methanol oxidation reaction (MOR) electrocatalysts, its utilization alone in DMFC systems is limited due to carbon monoxide (CO) poisoning, instability, methanol crossover, and high cost. These limitations impede the economic feasibility of Pt as an electrocatalyst. Herein, we present the use of powdered activated carbon (PAC) and granular activated carbon (GAC), both sourced from macadamia nut shells (MNS), a type of biomass. These bio-based carbon materials are integrated into hybrid supports with reduced graphene oxide (rGO), aiming to enhance the performance and reduce the production cost of the Pt electrocatalyst. Electrochemical and physicochemical characterizations of the synthesized catalysts, including Pt-rGO/PAC-1:1, Pt-rGO/PAC-1:2, Pt-rGO/GAC-1:1, and Pt-rGO/GAC-1:2, were conducted. X-ray diffraction analysis revealed crystallite sizes ranging from 1.18 nm to 1.68 nm. High-resolution transmission electron microscopy (HRTEM) images with average particle sizes ranging from 1.91 nm to 2.72 nm demonstrated spherical dispersion of Pt nanoparticles with some agglomeration across all catalysts. The electrochemical active surface area (ECSA) was determined, with Pt-rGO/GAC-1:1 exhibiting the highest ECSA of 73.53 m2 g−1. Despite its high ECSA, Pt-rGO/GAC-1:1 displayed the lowest methanol oxidation reaction (MOR) current density, indicating active sites with poor catalytic efficiency. Pt-rGO/PAC-1:1 and Pt-rGO/PAC-1:2 exhibited the highest MOR current densities of 0.77 mA*cm−2 and 0.74 mA*cm−2, respectively. Moreover, Pt-rGO/PAC-1:2 and Pt-rGO/PAC-1:1 demonstrated superior electrocatalytic mass (specific) activities of 7.55 mA/mg (0.025 mA*cm−2) and 7.25 mA/mg (0.021 mA*cm−2), respectively. Chronoamperometry tests revealed Pt-rGO/PAC-1:2 and Pt-rGO/PAC-1:1 as the most stable catalysts. Additionally, they exhibited the lowest charge transfer resistances and highest MOR current densities after durability tests, highlighting their potential for DMFC applications. The synthesized Pt supported on PACs hybrids demonstrated remarkable catalytic performance, stability, and CO tolerance, highlighting their potential for enhancing DMFC efficiency.

Tin–containing Silicon Oxycarbonitride Ceramic Nanocomposites as Stable Anode for Magnesium Ion Batteries

AbstractThe development of magnesium ion batteries as a viable alternative to lithium–ion batteries is impeded by the lack of efficient and stable electrode materials. Here, we present the synthesis of nanocomposites of tin–containing silicon oxycarbonitride (Sn/SiOCN) as anode materials for magnesium ion batteries (MIBs). The elemental and phase composition, morphology, and surface area of the nanocomposites are assessed by several characterization techniques. The galvanostatic cycling tests indicate a substantial initial discharging capacity for the anode with 42.2 wt . % of tin. Specifically, the first discharging capacities are 489.9 mA/g, 172.9 mA/g, and 136.6 mA/g at current densities of 0.5 mA/g, 50 mA/g, and 500 mA/g, respectively. After 100 cycles at a current density of 500 mA/g, the anode containing 33.8 wt % of tin exhibits a reversible capacity of 101.8 mAh/g and a remarkable rate performance efficiency of 76.5 %. Increasing tin content in the electrode materials increases the battery performance by decreasing electrode impedance and thus facilitating Mg2+ diffusion, as revealed by electrochemical impedance spectroscopy (EIS). Ex situ XRD and X‐ray photoelectron spectroscopy (XPS) characterizations following the magnesiation–demagnesiation process confirm the storage of reversible storage of Mg2+ ions in Sn/SiOCN electrode through incorporation in the SiOCN network and alloying/dealloying process involving Mg−Mg2Sn−Mg.