Understanding cathode materials in aqueous zinc–organic batteries

Organic electrode materials (OEMs) are being investigated as promising candidates for aqueous zinc-ion batteries (AZIBs) owing to their environmental friendliness, cost-effectiveness, and structural diversity, and tunability. Understanding the correlation between structural regulation of OEMs and their electrochemical property in AZIBs is vital to rational design of OEMs. Herein, we first discuss the fundamentals of the energy storage mechanism of OEMs. Then, strategies to improve the electrochemical performance, including the specific capacity, voltage, rate capability, and cycling stability, are elaborated from the perspective of molecular engineering. Finally, we share our views on the remaining challenges and prospects of OEMs in AZIBs.     

Recent Advances of Freestanding Cathodes for Li-S Batteries

Lithium-sulfur batteries (LSBs) with high energy density and low cost have been recognized as one of the most promising next-generation energy storage systems. Although it has taken decades of development, the practical application of LSBs has been hindered by several inherent obstacles, particularly the severe shuttle effect and sluggish reaction kinetics in the sulfur cathode. Various strategies have been proposed to address these problems via rational design of electrode materials and configurations. Freestanding sulfur cathode could be a promising strategy to improve the sulfur mass loading at the cathode level and energy density of LSBs. This minireview will briefly summary the recent advances in freestanding cathodes for LSBs. The advantages and disadvantages of various freestanding cathodes are discussed and the prospects for the development of flexible cathodes are envisioned.     

A technical review of face mask wearing in preventing respiratory COVID-19 transmission

Since the outbreak of the COVID-19 pandemic, most countries have recommended their citizens to adopt social distance, hand hygiene, and face mask wearing. However, wearing face masks has not been well adopted by many citizens. While the reasons are complex, there is a general perception that the evidence to support face mask wearing is lacking, especially for the general public in a community setting. Face mask wearing can block or filter airborne virus-carrying particles through the working of colloid and interface science. This paper assesses current knowledge behind the design and functioning of face masks by reviewing the selection of materials, mask specifications, relevant laboratory tests, and respiratory virus transmission trials, with an overview of future development of reusable masks for the general public. This review highlights the effectiveness of face mask wearing in the prevention of COVID-19 infection.     

Novel palladium nanoparticles supported on mesoporous natural phosphate: Catalytic ability for the preparation of aromatic hydrocarbons from natural terpenes

Various ratios of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) were prepared using the wetness impregnation method. The prepared catalysts were characterized by IR, XRD, CV, SEM, EDX, XRF, TEM and BET analysis. The reduction and preparation of the palladium nanoparticles afford a crystallite size of 10.88 nm. The performance of the synthesized catalyst was investigated in the solvent-free dehydroaromatization of α-, β- and γ-himachalene mixture from Cedrus atlantica oil as a model substrate. In order to achieve an efficient and selective catalysis, the catalytic dehydroaromatization of various terpenes such as limonene, limonaketone, carvone, carveol and perillyl alcohol was studied. The Pd@NP catalyst performed a high catalytic activity, selectivity and recyclability in the terpenes dehydroaromatization reaction.     

Two-Dimensional Germanium Sulfide Nanosheets as an Ultra-Stable and High Capacity Anode for Lithium Ion Batteries

Lithium ion batteries (LIBs) at present still suffer from low rate capability and poor cycle life during fast ion insertion/extraction processes. Searching for high-capacity and stable anode materials is still an ongoing challenge. Herein, a facile strategy for the synthesis of ultrathin GeS₂ nanosheets with the thickness of 1.1 nm is reported. When used as anodes for LIBs, the two-dimensional (2D) structure can effectively increase the electrode/electrolyte interface area, facilitate the ion transport, and buffer the volume expansion. Benefiting from these merits, the as-synthesized GeS₂ nanosheets deliver high specific capacity (1335 mAh g⁻¹ at 0.15 A g⁻¹), extraordinary rate performance (337 mAh g⁻¹ at 15 A g⁻¹) and stable cycling performance (974 mAh g⁻¹ after 200 cycles at 0.5 A g⁻¹). Importantly, our fabricated Li-ion full cells manifest an impressive specific capacity of 577 mAh g⁻¹ after 50 cycles at 0.1 A g⁻¹ and a high energy density of 361 Wh kg⁻¹ at a power density of 346 W kg⁻¹. Furthermore, the electrochemical reaction mechanism is investigated by the means of ex-situ high-resolution transmission electron microscopy. These results suggest that GeS₂ can use to be an alternative anode material and encourage more efforts to develop other high-performance LIBs anodes.     

Bipolar Electrochemistry Exfoliation of Layered Metal Chalcogenides Sb2S3 and Bi2S3 and their Hydrogen Evolution Applications

Efficient exfoliation and downsizing of Sb₂S₃ and Bi₂S₃ layered compounds by using scalable bipolar electrochemistry on their suspensions in aqueous media are here demonstrated. The resulting samples were characterized in detail by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy; their electrochemistry toward hydrogen evolution was also investigated. Hydrogen evolution ability of exfoliated Sb₂S₃ and Bi₂S₃ was investigated and compared to the bulk counterparts.     

Co-hydrolysis and Seed-Induced Synthesis of Basic Mesoporous ZSM-5 Zeolites with Enhanced Catalytic Performance

For zeolite catalysts, the regulation of active site and pore structure plays an important role in the enhancement of their catalytic performance. In this work, a one-pot and organic template-free co-regulation route is proposed to straightforwardly synthesize basic mesoporous ZSM-5 zeolites with adjustable alkaline-earth metal species. The synthesis pathway combines two decisive strategies: 1) the seed-induced interface assembly growth method and 2) the acidic co-hydrolysis/condensation of aluminosilicate species and alkaline-earth metal (e.g., Mg, Ca, Sr, or Ba) sources. It is interesting that the mesoporous structure was self-evolved through particle-attached seed-interfacial crystallization without the assistance of any template. Meanwhile, the incorporation of alkaline-earth metals species is homogeneous and highly dispersed in the solid products during the whole crystallization process, and finally generate the superior basicity. Catalysis tests of the as-synthesized samples displayed their novel performance in the typical base reaction of Knoevenagel condensation, even for bulky substrates owing to the enhanced diffusion arising from the meso/microporous network. This finding opens new possibilities for facile, cost-effective, and environmentally friendly synthesis of mesoporous high-silica zeolites with tunable acid/base properties, and deepens our understanding of the particle-attached crystallization.     

Galactose-Grafted 2D Nanosheets from the Self-Assembly of Amphiphilic Janus Dendrimers for the Capture and Agglutination of Escherichia coli

High aspect ratio, sugar-decorated 2D nanosheets are ideal candidates for the capture and agglutination of bacteria. Herein, the design and synthesis of two carbohydrate-based Janus amphiphiles that spontaneously self-assemble into high aspect ratio 2D sheets are reported. The unique structural features of the sheets include the extremely high aspect ratio and dense display of galactose on the surface. These structural characteristics allow the sheet to act as a supramolecular 2D platform for the capture and agglutination of E. coli through specific multivalent noncovalent interactions, which significantly reduces the mobility of the bacteria and leads to the inhibition of their proliferation. Our results suggest that the design strategy demonstrated here can be applied as a general approach for the crafting of biomolecule-decorated 2D nanosheets, which can perform as 2D platforms for their interaction with specific targets.