Search

The transition to a sustainable energy economy requires the availability of renewably produced hydrogen through proton exchange membrane water electrolysis. The techno‐economic viability of this technology requires addressing materials challenges regarding the lack of active and stable catalysts for the electrochemical oxygen evolution reaction (OER) in acidic conditions. Herein, core‐shell iridium/titanium dioxide (Core‐shell Ir@TiO2) catalysts for acidic OER are synthesized through a polyol method to create TiO2 nanoparticles, followed by urea reduction with Ir, and subsequent annealing in hydrogen. The formation process of the core‐shell structure is observed through in situ environmental transmission electron microscopy under annealing conditions. Ir segregation occurred from an initially blended mixed metal oxide structure to a core‐shell configuration at 500 °C. Core‐shell Ir@TiO2 showed a three‐fold higher stability number (i.e., S‐number) than commercial IrOx (3.34 × 106 versus 1.02 × 106). Furthermore, an Ir‐mass normalized activity of 1,880 A gIr−1 at 1.7 V versus RHE is measured for Core‐shell Ir@TiO2, compared to 624 A gIr−1 for commercial IrOx. The developed synthetic route to prepare a composite structure with a TiO2 core and Ir‐based shell has enabled an Ir content reduction without a compromise in activity and stability, thus offering a promising avenue for developing next‐generation catalysts tailored for acidic water electrolysis. [ABSTRACT FROM AUTHOR]

Partial electro‐oxidation using renewable electricity offers a sustainable route for valorizing glycerol, a major by‐product of biofuel production. This study introduces a bimetallic electrode with nanostructured platinum dendrites on nickel foam (Pt/NiF), achieving a peak geometric current density of 235 mA cm−2 and a Pt‐mass normalized current density of 3.71 AmgPt−1${\mathrm{A\ mg}}_{{\mathrm{Pt}}}^{ - {\mathrm{1}}}$ for glycerol electro‐oxidation at 0.92 V versus a reversible hydrogen electrode (RHE) in 3 m KOH electrolyte containing 1 m glycerol, outperforming most previously reported Pt‐containing catalysts. The Pt/NiF electrode demonstrates over 92% cumulative selectivity toward C3 products, with 64% selectivity for lactic acid at 0.65 V versus RHE over 5 h of testing. This research also highlights the role of chemical oxidation pathways (isomerization and rearrangements) in converting glycerol to lactic acid. After 5 h at 0.65 V versus RHE, the Pt/NiF electrode maintains 35% of its initial current density, plateauing at 12.2 mA cm−2 (0.15 AmgPt−1${\mathrm{A\ mg}}_{{\mathrm{Pt}}}^{ - {\mathrm{1}}}$), with performance loss likely due to surface poisoning by carbon‐based reaction intermediates/byproducts or passivating platinum (hydr)oxide species. These findings pave the way for developing low‐platinum group metal catalysts with high glycerol oxidation affinity and highlight the importance of considering chemical transformations during catalyst evaluation and reactor design. [ABSTRACT FROM AUTHOR]

The current global warming, coupled with the growing demand for energy in our daily lives, necessitates the development of more efficient and reliable energy storage devices. Lithium batteries (LBs) are at the forefront of emerging power sources addressing these challenges. Recent studies have shown that integrating hexagonal boron nitride (h‐BN) nanomaterials into LBs enhances the safety, longevity, and electrochemical performance of all LB components, including electrodes, electrolytes, and separators, thereby suggesting their potential value in advancing eco‐friendly energy solutions. This review provides an overview of the most recent applications of h‐BN nanomaterials in LBs. It begins with an informative introduction to h‐BN nanomaterials and their relevant properties in the context of LB applications. Subsequently, it addresses the challenges posed by h‐BN and discusses existing strategies to overcome these limitations, offering valuable insights into the potential of BN nanomaterials. The review then proceeds to outline the functions of h‐BN in LB components, emphasizing the molecular‐level mechanisms responsible for performance improvements. Finally, the review concludes by presenting the current challenges and prospects of integrating h‐BN nanomaterials into battery research. [ABSTRACT FROM AUTHOR]

The interest in bismuth-based anodes for energy storage devices has recently been heightened due to their high specific capacity, low working potential, excellent electrical conductivity, and environmentally friendly nature. However, capacity fading during early battery cycling is associated with solid electrolyte interphase forming and volume changes that result in performance loss and cyclic instability. In this study, we propose a strategy to engineer the interface of nanostructured Bi2Te3 particles with amorphous zirconium oxide nanocoating to enhance the performance of lithium-ion batteries (LIBs). The active nanomaterial was synthesized by mechanical alloying followed by low-temperature calcination of zirconium-(IV) oxynitrate at 280°C, which was predeposited on the particle surfaces via facile wet chemistry. X-ray photoelectron spectroscopy and transmission electron microscopy revealed that an amorphous ZrO2 shell with few nanometer thicknesses uniformly formed and covered the particle surfaces. It was also found that Te and Bi oxides were formed at the surface, which facilitated stable interfacial bonds with the oxide nanocoating. Electrochemical studies determined that the amorphous oxide ceramic slightly increased the electrical resistance but significantly reduced the Li+ diffusion coefficient (by an order of magnitude) and the formation of solid electrolyte phases. As a result, the discharge capacity of the nanostructured Bi2Te3 anode enhanced from 145.8 mAh g-1 to 245.1 mAh g-1 after interfacial engineering by 2-nm-thick amorphous ZrO2 nanocoating, while the stability was enhanced by three folds after 100 cycles at a current density of 0.5 C. The facile synthesis of amorphous nanocoating to engineer the interfacial of nanostructured anode materials paves the way to fabricate high-performance energy storage materials. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal dichalcogenides (TMDs) offer fascinating opportunities for fundamental nanoscale science and various technological applications. They are a promising platform for next generation optoelectronics and energy harvesting devices due to their exceptional characteristics at the nanoscale, such as tunable bandgap and strong light-matter interactions. The performance of TMD-based devices is mainly governed by the structure, composition, size, defects, and the state of their interfaces. Many properties of TMDs are influenced by the method of synthesis so numerous studies have focused on processing high-quality TMDs with controlled physicochemical properties. Plasma-based methods are cost-effective, well controllable, and scalable techniques that have recently attracted researchers' interest in the synthesis and modification of 2D TMDs. TMDs' reactivity toward plasma offers numerous opportunities to modify the surface of TMDs, including functionalization, defect engineering, doping, oxidation, phase engineering, etching, healing, morphological changes, and altering the surface energy. Here we comprehensively review all roles of plasma in the realm of TMDs. The fundamental science behind plasma processing and modification of TMDs and their applications in different fields are presented and discussed. Future perspectives and challenges are highlighted to demonstrate the prominence of TMDs and the importance of surface engineering in next-generation optoelectronic applications. [ABSTRACT FROM AUTHOR]

Smart and remote sensing technologies offer significant advantages across various applications. This study introduces an innovative approach integrating printed electrochemical nanosensors with a remotely controllable underwater robot, creating a "Robo-sensor" for underwater and surface water sensing. Unlike conventional underwater sensors, the Robo-sensor operates in three dimensions, both on the surface and underwater, targeting specific locations such as coastal areas and deep-sea environments while transmitting data to an external analytical unit. To achieve this, we developed a conductive nanoink by combining graphite, silver nanorods (AgNRs; diameter: 30 ± 20 nm, length: 2 ± 0.2 μm), nail polish as a cohesive agent, and an organic solvent. This ink was used to fabricate an electroanalytical system on the mini-robot's body. The Robo-sensor, connected to a portable potentiostat, demonstrated linear responses to hydroquinone (HQ) and nitrite ions, with detection ranges of 5.0-1356.0 and 3.0-1200.0 μM, respectively, under artificial seawater conditions (High salinity). Its repeatability (RSD <6%), stability (up to 40 continuous applications with an error < ± 10%), and sensitivity were thoroughly evaluated. The Robo-sensor's practical applications included detecting chemical leaks in underwater pipelines containing HQ, a hazardous chemical relevant to coastal industries such as petrochemicals. Additionally, it analyzed surface water contaminated with NO 2 - near and far from a wastewater discharge pipeline, providing valuable insights for environmental and ecosystem investigations. In conclusion, the developed Robo-sensor enables on-site analysis both on the surface and underwater, reducing time, costs, and risks in high-hazard environments like deep waters. With further modifications, this strategy could be adapted for diverse applications, including offshore oil and petrochemical operations, corrosion studies, and underwater environmental monitoring, thus expanding the real-world impact of electrochemical science.

Molybdenum disulfide (MoS 2 ) is a promising material for applications in sensors, energy storage, energy conversion devices, solar cells, and fuel cells. Because many of those applications require conductive materials, we recently developed a method for preparing a conductive form of MoS 2 (c-MoS 2 ) using dilute aqueous hydrogen peroxide in a simple and safe way. Here, we investigate modulating the chemical and mechanical surface properties of c-MoS 2 thin films using diazonium chemistry. In addition to a direct passivation strategy of c-MoS 2 with diazonium salts for electron-withdrawing groups, we also propose a novel in situ synthetic pathway for modification with electron-donating groups. The obtained results are examined by Raman spectroscopy and X-ray photoelectron spectroscopy. The degree of surface passivation of pristine and functionalized c-MoS 2 films was tested by exposing them to aqueous solutions of different metal cations (Fe 2+ , Zn 2+ , Cu 2+ , and Co 2+ ) and detecting the chemiresistive response. While pristine films were found to interact with several of the cations, modified films did not. We propose that a surface charge transfer mechanism is responsible for the chemiresistive response of the pristine films, while both modification routes succeeded at complete surface passivation. Functionalization was also found to lower the coefficient of friction for semiconducting 2H-MoS 2 , while all conductive materials (modified or not) also had lower coefficients of friction. This opens up a pathway to a palette of dry lubricant materials with improved chemical stability and tunable conductivity. Thus, both in situ and direct diazonium chemistries are powerful tools for tuning chemical and mechanical properties of conductive MoS 2 for new devices and lubricants based on conductive MoS 2 .

Layered-graphene reinforced-metal matrix nanocomposites with excellent mechanical properties and low density are a new class of advanced materials for a broad range of applications. A facile three-step approach based on ultra-sonication for dispersion of graphene nanosheets (GNSs), ball milling for Al-powder mixing with different weight percentages of GNSs, and equal-channel angular pressing for powders' consolidation at 200 °C was applied for nanocomposite fabrication. The Raman analysis revealed that the GNSs in the sample with 0.25 wt.% GNSs were exfoliated by the creation of some defects and disordering. X-ray diffraction and microstructural analysis confirmed that the interaction of the GNSs and the matrix was almost mechanical, interfacial bonding. The density test demonstrated that all samples except the 1 wt.% GNSs were fully densified due to the formation of microvoids, which were observed in the scanning electron microscope analysis. Investigation of the mechanical properties showed that by using Al powders with commercial purity, the 0.25 wt.% GNS sample possessed the maximum hardness, ultimate shear strength, and uniform normal displacement in comparison with the other samples. The highest mechanical properties were observed in the 0.25 wt.% GNSs composite, resulting from the embedding of exfoliated GNSs between Al powders, excellent mechanical bonding, and grain refinement. In contrast, agglomerated GNSs and the existence of microvoids caused deterioration of the mechanical properties in the 1 wt.% GNSs sample., Competing Interests: The authors declare no conflict of interest.