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Rechargeable aqueous zinc-ion batteries (AZIBs) have garnered widespread attention due to their low cost, non-flammability, eco-friendliness, and abundant anode element content, with the potential to supplant lithium-ion batteries. Nevertheless, their development is hindered by zinc dendrite growth, corrosion passivation, the hydrogen evolution reaction (HER), and active material decomposition, severely impairing the cycling lifespan and coulombic efficiency of AZIBs. As a cathode material, sulfur offers superior theoretical capacity, non-toxicity, and lower cost compared to traditional aqueous zinc-ion battery active materials, thus compensating for the shortcomings of low discharge capacity and insufficient overall energy density in AZIBs. Although research on aqueous zinc-sulfur batteries (AZSBs) is relatively scarce, their exceptional performance has yielded outstanding results. This paper first reviews the cathode materials and reaction mechanisms of aqueous zinc–sulfur batteries, and then systematically analyzes the pertinent electrochemical performance data following the latest research on electrolyte modification and additive engineering. Subsequently, we discuss and analyze potential solutions to the existing impediments in zinc–sulfur batteries. Finally, based on an analysis of current research findings, we propose future research directions with the aim of providing inspiration to overcome the latent challenges facing aqueous zinc-sulfur batteries. [ABSTRACT FROM AUTHOR]

Both polyoxometalates (POMs) and organic small molecular catalysts show excellent performance in chemical synthesis. The incorporation of nanoscale POMs and organocatalysts allows the full expression of their respective merits and enables elusive reactions to be achieved in one catalytic system. However, the covalent combination of such two components has been rarely explored. Here, we have successfully designed and synthesized a bifunctional nanomolecular catalyst L -Pro-Mn-Anderson by grafting L -proline onto an Mn-Anderson POM for the first time, and catalytic experiments show that L -Pro-Mn-Anderson can realize the one-pot alcohol oxidation/three-component reaction to synthesize two types of heterocyclic compounds (5-aryl-pyrimido[4,5-b]quinoline-dione derivatives and pyrazolo[3,4-b] pyridine derivatives) in high yields up to 97%. The detailed characterization of the catalyst and the catalytic mechanism has shown that L -Pro-Mn-Anderson exhibits synergistic effects that combine both organic and inorganic catalytic functions, and the covalent linkage improves the overall redox activity of the molecular catalyst. This study opens up a new way for the design and application of covalently combined organic–inorganic molecular catalysts toward de novo organic synthesis. [ABSTRACT FROM AUTHOR]

A Keggin-type polyoxometalate-based crystalline complex, [(SiMo12O40)Cu6(2,2′-bipy)6(Mo6O22)] (complex 1), has been prepared by using a Waugh-type polyoxometalate building block [MnMo9O32]6−, and for the first time, Waugh-type polyoxometalate was converted to a Keggin-type structure under hydrothermal conditions by using a Teflon-lined reactor with glass vials. The synthesized complex was characterized by single-crystal and powder X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis. Structural characterization results show that complex 1 comprises Keggin-type [SiMo12O40]4− anions and [Cu6(2,2′-bipy)6(Mo6O22)]4+ cation moieties composed of isopolymolybdates with 2,2′-bipy-coordinated copper ions, leading to a three-dimensional (3D) supramolecular network. This polyoxometalate assembly exhibits excellent photocatalytic properties and good cyclic stability for the photodegradation of methylene blue (MB) dye. In addition, the experimental results demonstrate that complex 1 also possesses outstanding electrocatalytic activity for nitrite reduction. [ABSTRACT FROM AUTHOR]

Electroreduction of greenhouse gas CO2 into value-added fuels and chemicals provides a promising pathway to address the issues of energy crisis and environmental change. However, the regulations of the selectivity towards C2 product and the competing hydrogen evolution reaction (HER) are major challenges for CO2 reduction reaction (CO2RR). Here, we develop an interface-enhanced strategy by depositing a thin layer of nitrogen-doped graphene (N-G) on a Cu foam surface (Cu-N-G) to selectively promote the ethanol pathway in CO2RR. Compared to the undetectable ethanol selectivity of pure Cu and Cu@graphene (Cu-G), Cu-N-G has boosted the ethanol selectivity to 33.1% in total Faradic efficiency (FE) at −0.8 V vs. reversible hydrogen electrode (RHE). The experimental and density functional theory (DFT) results verify that the interconnected graphene coating can not only serve as the fast charge transport channel but also provide confined nanospace for mass transfer. The N doping can not only trigger the intrinsic interaction between N in N-G and CO2 molecule for enriching the local concentration of reactants but also promote the average valence state of Cu for C-C coupling pathways. The confinement effect at the interface of Cu-N-G can not only provide high adsorbed hydrogen (Had) coverage but also stabilize the key ⋆HCCHOH intermediate towards ethanol pathway. The provided interface-enhanced strategy herein is expected to inspire the design of Cu-based CO2RR electrocatalysts towards multi-carbon products. [ABSTRACT FROM AUTHOR]

The carbon–carbon bond cleavage of 1,2-diols is an important chemical transformation. Although traditional stoichiometric and catalytic oxidation methods have been widely used for this transformation, an efficient and valuable method should be further explored from the views of reusable catalysts, less waste, and convenient procedures. Herein an inorganic-ligand supported iron catalyst (NH4)3[FeMo6O18(OH)6]·7H2O was described as a heterogeneous molecular catalyst in acetic acid for this transformation in which hydrogen peroxide was used as the terminal oxidant. Under the optimized reaction conditions, carbon–carbon bond cleavage of 1,2-diols could be achieved in almost all cases and carboxylic acids or ketones could be afforded with a high conversion rate and high selectivity. Furthermore, the catalytic system was used efficiently to degrade renewable biomass oleic acid. Mechanistic insights based on the observation of the possible intermediates and control experiments are presented. [ABSTRACT FROM AUTHOR]

A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8 as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid. [ABSTRACT FROM AUTHOR]

Organo disulfides represent an abundant class of compounds in chemical biology, pharmaceutical fields, and industry. They are traditionally synthesized by the oxidation of mercaptan in the presence of an organic ligand supported metal catalyst or toxic oxidants under harsh conditions. Here, we disclose a highly-efficient pathway in which disulfide is synthesized by organic boric acid and Na2S2O3 using the catalyst (NH4)3[CrMo6O18(OH)6], demonstrating a high activity and excellent selectivity. Various boric acid derivatives have been successfully transformed into the corresponding disulfides. Mechanistic insights have been furnished based on the observation of intermediate and control experiments. [ABSTRACT FROM AUTHOR]

We report an efficient method for the oxidative dehydrogenation of hydrazines and diarylamines in aqueous ethanol using Anderson-type polyoxomolybdate-based iron(III) as a catalyst and hydrogen peroxide as an oxidant. A series of azo compounds and tetraarylhydrazines were obtained in moderate to excellent yields. The reaction conditions and substrate scopes are complementary or superior to those of more established protocols. In addition, the catalyst shows good stability and reusability in water. The preliminary mechanistic studies suggest that a radical process is involved in the reaction. [ABSTRACT FROM AUTHOR]

Aimed at energy conservation and water saving for the lab, we have designed and constructed one kind of lab-scale small recirculating device of cooling water utilizing a water recirculator coupled to a solar energy system via a self-made multifunctional voltage regulator, which is equipped with an active heat radiator and powered by a solar energy system. It can provide cooling water for 1-3 sets of ordinary refluxing setups in series without additional consumption of water and electricity. The temperature difference between the water in the bucket and the environment is less than 4 °C for eight common solvents in single refluxing set-up or three combined refluxing setups with different solvents in series. In the performance assessment experiments for the refluxing of eight common solvents with different boiling point, the largest solvent loss is less than 6% if the condenser is open to the air in the refluxing time of 8 h, but none obvious solvent loss are found if the condensers were equipped with an oil bubbler. Control experiments indicates that the preparation of bromoethane/ethyl acetate/propyl hexanoate using our water recirculator can achieve almost unanimous yields in relative to those reactions using tap water as cooling water., (© 2024. The Author(s).)

A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K 2 S 2 O 8 as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.