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Layered manganese transition metal oxides, such as NaMnO2, have attracted great interest due to the low cost and high capacity. However, complex phase transitions in NaMnO2 lead to poor cycling stability. The introduction of Li doping has been confirmed to improve the performance of NaMnO2. O3-type NaLi1/3Mn2/3O2 (NLMO), synthesized in 2021, has demonstrated excellent electrochemical performance. Notably, irreversible Li interlayer migration (Li migrates from the transition metal layer to the alkali metal layer) has been observed during cycling, which is related to the electrochemical performance. Therefore, it is crucial to understand the mechanism underlying Li interlayer migration in O3-NLMO. However, the environment of Li interlayer migration on cycling is complex and involves interlayer spacing, Na-ion concentration, the degree of O-ion oxidation, and phase transition. Here, in this work, we utilized the first-principles method to decouple the coupling factors influencing the Li interlayer migration. Through analyzing the impact of the single-factor on Li interlayer migration, we aim to identify the crucial factors affecting this process. Our results show that a decrease in Na-ion concentration and an increase in O-ion oxidation degree promote the Li interlayer migration, while the O–P phase transition suppresses the Li interlayer migration. Interlayer spacing was found to play a less influential role in Li interlayer migration. Our investigations provide effective strategies for the subsequent regulation of Li interlayer migration. [ABSTRACT FROM AUTHOR]

Magnetometer cell wall coat molecules play an important role in preserving the lifetime of pumped alkali metal atoms for use in magnetometers that are capable of measuring very small magnetic fields. The goal of this study is to help rationalize the design of the cell coat molecules. Rubidium-87 is studied in terms of its interaction with three template cell coat molecules: ethane, ethene, and methyltrichlorosilane (MeTS). Ab initio electronic structure methods are applied to investigate the effect that the coat molecules have on the 2S ground state and 2P excited state of 87Rb. We find that, from the ab initio results, the three template molecules have differing effects, with MeTS having the largest effect on the ground state and ethane or ethene having the largest effect on the non-degenerate excited states. [ABSTRACT FROM AUTHOR]

Alkali metal doping of multi-walled carbon nanotubes is of great interest, both fundamentally to explore the effect of dopants on quasi-one-dimensional electrical systems and for energy applications such as alkali metal storage. We present an investigation with complementary photoemission and Raman spectroscopies, fully carried out in an ultra-high vacuum, to unveil the electronic and vibrational response of a forest of highly aligned multi-walled carbon nanotubes by in situ potassium doping. The charge donation by the alkali adatoms induces a plasmon mode, and the density of states undergoes an energy shift consistent with electron donation and band filling of the multi-walled carbon nanotube band structure. The π-states in the valence band and the Raman peaks unveil an evolution that can be ascribed to charge donation and partially to a tensile strain exerted by the K adatoms on the carbon lattice. All these effects are thermally reversible, fostering these materials as a potential system for electronic charge harvesting. [ABSTRACT FROM AUTHOR]

Alkali metal dosing has nowadays been extensively used in angle-resolved photoemission spectroscopy (ARPES) for the in situ surface electron doping of materials to provide access to the unoccupied states. This technique also gives rise to nontrivial physical phenomena, such as the appearance of quantum well states and effects due to alkali metal intercalation. Here, we uncovered a previously unobserved type of electronic behavior induced by alkali metal dosing. By employing ARPES to study the evolution of the electronic structure of the Ti2O3 thin film upon rubidium (Rb) dosing, we found that the electron chemical potential of the system remains unchanged throughout the process. Interestingly, a series of electron-like band dispersions first appear with Rb dosing. A further increase in the Rb dosage leads to the eventual disappearance of the electron-like bands and the emergence of a set of hole-like bands. Our finding enriches the phenomenology brought about by alkali metal surface dosing, suggesting a novel functionality of this popular surface doping technique. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a two-dimensional, mechanically strong, and chemically tunable material for separations. Elucidating GO–ion–water interactions at the molecular scale is highly important for predictive understanding of separation systems. However, direct observations of the nanometer region by GO surfaces under operando conditions are not trivial. Therefore, thin films of GO at the air/water interface can be used as model systems. With this approach, we study the effects of alkali metal ions on water organization near graphene oxide films at the air/water interface using vibrational sum frequency generation (SFG) spectroscopy. We also use an arachidic acid Langmuir monolayer as a benchmark for a pure carboxylic acid surface. Theoretical modeling of the concentration-dependent sum frequency signal from graphene oxide and arachidic acid surfaces reveals that the adsorption of monovalent ions is mainly controlled by the carboxylic acid groups on graphene oxide. An in-depth analysis of sum frequency spectra reveals at least three distinct water populations with different hydrogen bonding strengths. The origin of each population can be identified from concentration dependent variations of their SFG signal. Interestingly, an interfacial water structure seemed mostly insensitive to the character of the alkali cation, in contrast to similar studies conducted at the silica/water interface. However, we observed an ion-specific effect with lithium, whose strong hydration prevented direct interactions with the graphene oxide film. [ABSTRACT FROM AUTHOR]

The cathodic catalytic activity for the oxygen reduction reaction (ORR) plays a critical role in determining the performance of proton-conducting solid oxide fuel cells (P-SOFCs). BaCo 0.4 Fe 0.4 Zr 0.2 O 3-δ (BCFZ) has emerged as a promising cathode for P-SOFCs due to its triple-phase conductivity. Nevertheless, its suboptimal proton conductivity and hydration ability at intermediate temperatures prevent it from achieving the anticipated ORR catalytic activity. To address these limitations, this study explores the enhancement of electrocatalytic activity in BCFZ through alkali metal doping and A-site defect construction. The effects of such modifications on oxygen surface exchange kinetics and ORR catalytic activity are systematically investigated. The findings reveal that BCFZ exhibits relatively low parameters in terms of electronic conductivity, oxygen ion conductivity, oxygen vacancy concentration, k chem , and D chem. Conversely, these parameters are markedly improved in A-site deficient BCFZ (D-BCFZ) and Na/K-doped BCFZ. Consequently, the enhancement of these properties yields a significant increase in ORR catalytic activity, with D-BCFZ demonstrating the best electrochemical performance. Specifically, P-SOFC with D-BCFZ cathode achieves an R p value of just 0.073 Ω cm2 and a P max value of 0.928 W cm−2 at 650 °C. This study provides theoretical insight into the mechanisms by how alkali metal doping and defect construction enhance the ORR catalytic activity of BCFZ. These findings offer valuable guidance for the development and optimization of high-performance P-SOFC cathodes. [ABSTRACT FROM AUTHOR]

Low stability deriving from the accumulation of moisture and intermediates represents the major challenge for practical applications of manganese oxides (MnO x) for ozone elimination. Here, Li+, Na+ and K+ were successfully introduced into the channel framework of amorphous MnO x to improve its stability through a simple post-treatment method. Alkali metal modification can promote the removal of ozone by amorphous MnO x , and Na-MnO x exhibited superior catalytic activity and remarkable stability in water-resistance, cycling and long-term tests. The Na introduction facilitated the formation of oxygen vacancies, and improved low-temperature reducibility and lattice oxygen mobility. The mechanism of ozone decomposition on amorphous MnO x and Na-MnO x catalysts was deeply investigated by in situ diffuse reflectance infrared Fourier transform spectra (in-situ DRIFTS). The Na addition strengthened the hydrophobicity of oxygen vacancies, but also greatly boosted the desorption of intermediate oxygen species and the ozone decomposition cycle. [Display omitted] [ABSTRACT FROM AUTHOR]

Alkali metal catalysts show great application potential in the gasification process of coal attributed to their characteristics of high activity and reusability. However, this type of catalysts has strong water absorption, which causes the agglomerating during storage and limits pipeline transportation by water. In order to solve the hydration of alkali metal catalysts and to release them at the target temperatures, they were encapsulated by cost effective and environment friend inorganic materials. The capsules were fabricated through in situ formation of calcium carbonate as shell. The water resistance, water erosion resistance and shell rupture temperature of the capsules were tested. And the effect of temperature on the properties of capsules was studied. The microstructure and composition were characterized by SEM and XRD. The results showed that the best performance of the capsules was obtained after heat treatment at 600 °C, with the pH of catalyst solution was reduced from 13.65 to 10.89 before and after encapsulation. The percentage of capsule breakage after 2 h of water scouring was 8.46 %. And the catalysts were fully released between 700–750 °C due to the crack of shell. The shell was composed mainly of CaCO 3 -AlPO 4 -Al 4 (P 2 O 7) 3. The shell was porous in the middle, gradually denser outwards, and eventually formed a dense layer in the outer layer. This was attributed to the volume expansion caused by the reaction of calcium oxide and calcium hydroxide to form calcium carbonate. This study provides a novel approach for the transportation of alkali metal catalyst and expands its application in coal gasification. [Display omitted] • The alkali metal catalysts were successfully encapsulated by CaCO 3 shells. • The pH of catalyst was reduced from 13.65 to 10.89 before and after encapsulation. • The percentage of capsule breakage after 2 h of water scouring was 8.46 %. • The catalysts were fully released between 700–750 °C due to the crack of shell. [ABSTRACT FROM AUTHOR]

The development of lead-free primary explosives is urgent from industrial and military aspects. Herein, a typical energetic molecule with the dinitromethyl group and tetrazole ring was selected as the ligand for different alkali metals (Na, K, Rb, and Cs) to achieve a series of energetic coordination polymers (ECPs), namely, ECP 1 to ECP 4. The DNMT molecule showed outstanding coordination ability with metal ions to form diverse metal complexes and coordination frameworks. It was found that the conformation of the energetic ligand as well as the framework structure can be tuned by the deprotonation of DNMT and the corresponding metal centers. Interestingly, a rare metal–π(tetrazole) coordinate bond was also observed in ECP 3, which is valuable for designing new ECPs and energetic metal complexes (EMCs). A new method has been developed for predicting the energetic properties of EMCs and ECPs. The calculation results indicate that the DNMT-based ECPs have good detonation performance and can be used as lead-free primary explosives. Moreover, the perforated lead plate test reveals the extensive application of the DNMT-based ECPs in emerging laser-initiated explosives. Compared to pure DNMT, the DNMT-based ECPs show significantly enhanced thermal stability. The mechanisms behind different detonation performances and thermal stabilities among the DNMT-based ECPs were also discussed. All the results will be valuable for the future development of ECPs in the applications of lead-free primary explosives. [ABSTRACT FROM AUTHOR]

BACKGROUND: A material of natural origin, clinoptilolite, was modified with selected metals in order to obtain a catalyst for the conversion of xylose – the main component of the hemicellulose fraction present in lignocellulosic biomass – to selected carboxylic acids. RESULTS: The starting material without modification (0‐parent), the hydrogen form (0‐hydrogen) of zeolite and zeolite after hierarchization with hydrochloric acid (0‐dealuminated) were used. Iron, copper and cobalt ions were introduced as active centers using the sonication technique. The catalytic process was carried out in a pressure autoclave for 2 h at a temperature of 220 °C. Compounds such as formic acid with a yield of 91% (0‐parent) and lactic acid with a yield of 66.1% (Fe‐hydrogen) were obtained. Conclusion: The catalytic processes carried out using xylose lead to the obtaining of a mixture of carboxylic acids: lactic acid, pyruvic acid and formic acid. An important role here is played by the presence of iron as an active site, which leads to the transformation of xylose into lactic acid by dehydration, and the presence of Lewis and Brønsted active sites. In the case of formic acid, which has never been reported in publications on a similar topic, the starting zeolite without modification contributed to its preparation. It is possible that the content of alkali metals contributed to its preparation along with the coupling of the oxidation reaction of the intermediate product, because of the presence of small amounts of iron, which are present in the natural material. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: Magnesium oxide (MgO) is favored for solid‐state carbon dioxide (CO2) capture due to its high theoretical adsorption capacity, abundant reserves, low cost, and environmental friendliness. However, its practical application in industry is hindered by low CO2 adsorption capacity under moderate operating conditions. In this work, MgO was modified by a deposition method using LiNO3, NaNO3, KNO3, Na2CO3 and K2CO3 as additives. RESULTS: The study determines optimal ratios within the [(Li, Na, K)x − (Na, K)]y/MgO system, specifically identifying x = 0.5 and y = 0.15 as most effective. At 275 °C under pure CO2 conditions, the adsorption capacity peaks at 0.631 g CO2 g−1 adsorbent. Effective regeneration of the adsorbent occurs at 400 °C under 100% N2 for 15 min. Under Integrated Gasification Combined Cycle (IGCC) conditions, the adsorption capacity stabilizes at 0.462 g g−1 after 20 cycles, representing a 25% decrease from initial capacity. CONCLUSION: Experimental findings demonstrate that the inclusion of alkali metal salts in MgO precursors enhances the adsorbent's microstructure, thereby improving its CO2 capture efficiency and bolstering cycling stability. This research enhances our understanding of the factors influencing CO2 adsorption and cyclic stability in alkali metal salt‐promoted MgO, providing valuable insights for further refinement in the formulation and synthesis protocols of MgO‐based CO2 adsorbents. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

High-energy-density alkali metal batteries (AMBs) offer a potentially promising and sustainable option for energy storage. However, notorious dendrite growth and uncontrollable plating behaviors resulting from random spatial ion/atom distribution and related high barriers restrict the development of AMBs. Different from interphase engineering and architecture construction, the emerging catalysis modulation is proposed to overcome above-related barriers, achieving uniform alkali metal nucleation and atom diffusion. Among the various catalysts, single atom catalysts (SACs) exhibit an atomic exposure of nearly 100%, displaying high atomic catalytic capability and efficiency. Although it is still at an early stage, the adoption of SACs for modulating alkali metal ion/atom desolvation or diffusion has shown great promise in both fundamental research and practical applications. In this review, the fabrications and characterizations of SACs are briefly summarized, and the principal mechanisms of SAC-incorporated alkali metal anode systems are highlighted in terms of electrochemical analysis, microscopic/spectroscopic characterizations, and theoretical simulations. In addition, sustainable paths for future critical battery chemistry and material selections based on SACs are highlighted. The associated opportunities and challenges are further prospected to achieve a high-performance alkali metal anode. [ABSTRACT FROM AUTHOR]

Electrochemical energy storage systems based on sulfur and lithium can theoretically deliver high energy with the further benefit of low cost. However, the working mechanism of this device involves the dissolution of sulfur to high‐molecular weight lithium polysulfides (LiPs with general formula Li2Sn, n≥4) in the electrolyte during the discharge process. Therefore, the resulting migration of partially dissociated LiPs by diffusion or under the effect of the electric field to the lithium anode, activates an internal shuttle mechanism, reduces the active material and in general leads to loss of performance and cycling stability. These drawbacks poses challenges to the commercialization of Li/S cells in the short term. In this study, we report on the decoration of reduced graphene oxide with MoO3 particles to enhance interactions with LiPs and retain sulfur at the cathode side. The combination of experiments and density functional theory calculations demonstrated improvements in binding interactions between the cathode and sulfur species, enhancing the cycling stability of the Li/S cells. [ABSTRACT FROM AUTHOR]

Unlocking the full potential of hydrogen as a clean fuel requires overcoming the challenge of efficient storage. A promising method involves utilizing metals decorated, high surface area materials for hydrogen storage. We employed density functional theory (DFT) calculations to investigate how H 2 molecules interact with h-BNNT decorated by alkali metals (AM) and transition metals (TM). The h-BNNT's stability is confirmed by negative cohesive energy, positive phonon dispersion curves, and room temperature AIMD calculations. Our calculations reveal that the adsorption energies of H 2 molecules on AM/TM decorated h-BNNT fall within the physisorption regime. Notably, Na, K, and Au decorated surfaces can store up to seven H 2 molecules each, while Cu and Ag atom can bind up to eight. Li atom, however, can only accommodate six H 2 molecules around it. We also predicted that under optimal conditions, h-BNNT decorated with a high concentration of AM/TM could achieve a hydrogen storage capacity of 3.77–6.72 wt%. This highlights the potential of decorated h-BNNT as a material for hydrogen storage medium. [Display omitted] • Alkali and transition metals decorated on hexagonal boron nitride nanotubes (h-BNNTs) are promising for hydrogen storage medium. • Single alkali metals (AM) and transition metals (TM) adsorbed six to eight H 2 molecules. • The average adsorption energy per H 2 molecule on AM/TM decorated h-BNNT is in the range of −0.177 to −0.299 eV/H 2. • Gravimetric weight percentage capacity (wt%) is in the range of 3.77–6.72 % for hydrogen storage. [ABSTRACT FROM AUTHOR]

The rapid advancement of clean energy has aroused an increased demand for advanced energy storage systems. Alkali metal‐ion batteries (AMIBs) including lithium/sodium/potassium‐ion batteries (LIBs/SIBs/PIBs) play a crucial role in these systems, and their development is closely related to the progress of electrode materials. Niobium (Nb)‐based materials exhibit distinctive features such as quasi‐2D framework, high intercalation potential, robust pseudo‐capacitance effect, and minimal volume expansion during cycles. These characteristics render them highly valuable for energy storage applications. However, the low conductivity and limited capacity of Nb‐based electrode materials significantly limit their widespread development in energy storage applications. To address these challenges, various strategies have been explored. This review primarily summarizes the recent advancements in research on Nb‐based anode materials for AMIBs over the past decade. The synthesis strategy, structure design, and material composite of Nb‐based materials are systematically discussed, and the performances of different types of batteries are also well analyzed and compared. Meanwhile, their merits in the fast‐charging realm are then highlighted. Importantly, this review presents the key issues and challenges encountered by Nb‐based anode materials in future energy storage, along with novel concepts and solutions for the research and development of next‐generation Nb‐based anodes. [ABSTRACT FROM AUTHOR]

In order to alleviate the influence of greenhouse effect on global climate change, the effective utilization of CO2 to prepare fine chemicals should be paid more attention to, however, which is greatly blocked by the catalyst with low efficiency. Here, alkali metal (Li, Na, or K) are employed as a modification aid to prepare CuO/ZrO2 catalyst for CO2 hydrogenation to methanol. The effects of alkali metal on physicochemical properties and catalytic activities of CuO/ZrO2 catalyst were studied in detail by the XRD, N2‐physisorption, ICP‐OES, SEM/EDS, H2/N2O/CO2/NH3‐chemisorption, and evaluation test. The results verified that the use of complex combustion method enabled the uniform combination of all components in precursor. High‐temperature calcination (700 °C) further enhanced the strong interaction and synergistic effect between Cu and ZrO2. Most importantly, the introduction of alkali metal effectively altered the structure and catalytic activity of CuO/ZrO2 catalysts. However, the selectivity to methanol increased while the CO2 conversion decreased regardless of different kinds of alkali metal being introduced to the CuO/ZrO2 catalysts. For example, CuO/ZrO2 catalyst modified by K exhibited excellent performance for methanol production that 98.9% selectivity of methanol based on 8.8% conversion of CO2 after 48 h online reaction. [ABSTRACT FROM AUTHOR]

A computational mechanistic study was performed to investigate the transfer hydrogenation of styrene catalysed by a potassium tris‐hexamethyldisilazide magnesiate in the presence of 1,4‐cyclohexadiene. Exploiting cooperative effects between Mg and K centres present in this tris(amide) complex results in the selective formation of the desired product ethylbenzene. The calculations demonstrate the synergy of the metal centres within the bimetallic complex, since neither the monometallic potassium amide K(HMDS) nor the magnesium amide Mg(HMDS)2 on their own can efficiently execute this transformation under the experimental conditions. Several distinct mechanistic pathways have been explored, leading to the identification of the most plausible sequence in which both metal centres act in a synchronised manner. [ABSTRACT FROM AUTHOR]

High-yielding synthetic routes to five new extremely bulky aminopyridine pro-ligands were developed, viz. (C5H3N-6-Ar1)N(H)Ar2-2; Ar1 = Trip, Ar2 = TCHP (HAmPy1), Ar* (HAmPy2) or Ar† (HAmPy3); Ar1 = TCHP, Ar2 = Ar* (HAmPy4) or Ar† (HAmPy5) (Trip = 2,4,6-triisopropylphenyl, TCHP = 2,4,6-tricyclohexylphenyl, Ar* = C6H2(CHPh2)2Me-2,6,4, Ar† = C6H2(CHPh2)2Pri-2,6,4. Four of these were deprotonated with LiBun in diethyl ether to give lithium aminopyridinate complexes which were dimeric for the least bulky ligand, [{Li(AmPy1)}2] or monomeric for the bulkier aminopyridinates, i.e., in [Li(AmPy2−4)(OEt2)]. One aminopyridine was deprotonated with MeMgI to give monomeric [Mg(AmPy3)I(OEt2)2]. When treated with sodium or potassium mirrors or 5% w/w Na/NaCl, over-reduction occurred, leading to the alkali metal aminopyridinates, [M(AmPy3)(η6-toluene)] (M = Na or K) or [{Na(AmPy3)}∞]. An attempted reduction of [Mg(AmPy3)I(OEt2)2] with a dimagnesium(I) compound led only to partial loss of diethyl ether and the formation of [(AmPy3)Mg(μ-I)2Mg(AmPy3)(OEt2)]. All prepared complexes have potential as ligand transfer reagents in salt metathesis reactions with metal halide complexes. [ABSTRACT FROM AUTHOR]

The quest for alternative energy sources has been spurred by the drawbacks and environmental risks of fossil fuels, with hydrogen emerging as a viable contender. But finding materials that can effectively store hydrogen with the best adsorption energy is a major obstacle to building a hydrogen‐based economy. As a result, a significant amount of research has been conducted worldwide to examine fullerene's (C60) potential for hydrogen adsorption. The results of extensive DFT calculations are presented here, pertaining to the adsorption of hydrogen molecules onto fullerenes doped with alkali metals, namely Rubidium (Rb), Ceasium (Cs), and Fransium (Fr). The study analyzes a number of parameters, such as global properties, electronic, optical, and surface annihilation energy. These analyses are performed using the Gaussian 09 simulation package with the 6–31G/B3LYP level of theory DFT methodology. The findings show that an exothermic process is involved in the adsorption of hydrogen onto fullerene doped alkali elements, as evidenced by the negative adsorption energy. The attractive interactions between the polarized dipole of hydrogen molecules and the surface dipole of doped fullerenes can be the cause of this exothermicity. These results imply that fullerenes decorated with alkali metals are promising as likely hydrogen storage media. [ABSTRACT FROM AUTHOR]

The extraction of the solid state materials "MSnBix" (M/x=Cs/1, Na/3) in liquid ammonia in the presence of different chelating agents yielded the novel Zintl anion [Sn5Bi3]3−. The anion could be crystallized and characterized via single crystal X‐ray diffraction in [Cs@[18]crown‐6]3[Sn5Bi3] ⋅ 7NH3, [K@[18]crown‐6]1.5[Cs@[18]crown‐6][Cs@([18]crown‐6)2]0.5[Sn5Bi3] ⋅ 3.98NH3, [Na@DB[18]crown‐6]2[Na(NH3)6][Sn5Bi3] ⋅ 14NH3 and [Cs@[2.2.2]crypt]6[Sn5Bi3]2 ⋅ 9.53NH3. The [Sn5Bi3]3− anion is further investigated by mass spectrometry and DFT calculations to confirm its composition and elucidate its electronic structure. [ABSTRACT FROM AUTHOR]

In this study, first‐principles calculations are used to systematically study the structural, mechanical, and optical properties of the honeycomb AuTe monolayer, as well as the influence of layered structures on their stability and electronic properties. Additionally, the effect of alkali metal atoms decorating AuTe‐X (X = Li, Na, K) and related structural, electronic, optical, and topological insulator properties, along with the biaxial strain on the lithium‐decorated AuTe‐Li monolayer are investigated. The AuTe monolayer shows metallic characteristics, and when alkali metal atoms are decorated onto it, the resulting structures remain dynamically stable. Notably, the introduction of Li, Na, and K atoms induces bandgap opening in the decorated Li and Na monolayers near the Fermi level, causing metal‐to‐narrow bandgap semiconductor and Dirac semi‐metal transitions. Conversely, the metallic nature of the decorated AuTe‐K monolayer is retained. The emergence of a bandgap near the Fermi level, caused by alkali metal decoration, triggers a topological phase transition in AuTe‐Li, AuTe‐Na, and AuTe‐K monolayers. Optical analyses reveal that AuTe‐K decorated structure enhances light absorption in the visible spectrum. Consequently, the findings provide insights into the decoration of these two‐dimensional material monolayers, potentially advancing research and motivating the production of such monolayers for current nanodevice applications. [ABSTRACT FROM AUTHOR]

The extraction of the solid state materials "MSnBix" (M/x=Cs/1, Na/3) in liquid ammonia in the presence of different chelating agents yielded the novel Zintl anion [Sn5Bi3]3−. The anion could be crystallized and characterized via single crystal X‐ray diffraction in [Cs@[18]crown‐6]3[Sn5Bi3] ⋅ 7NH3, [K@[18]crown‐6]1.5[Cs@[18]crown‐6][Cs@([18]crown‐6)2]0.5[Sn5Bi3] ⋅ 3.98NH3, [Na@DB[18]crown‐6]2[Na(NH3)6][Sn5Bi3] ⋅ 14NH3 and [Cs@[2.2.2]crypt]6[Sn5Bi3]2 ⋅ 9.53NH3. The [Sn5Bi3]3− anion is further investigated by mass spectrometry and DFT calculations to confirm its composition and elucidate its electronic structure. [ABSTRACT FROM AUTHOR]

Industrial sulfuric acid waste catalysts contain a large amount of vanadium, sodium, potassium, sulfur, and a small amount of aluminum, iron, and arsenic. They are often used as important raw materials for extracting vanadium and alkali metal salts. Rapid and accurate determination of relevant components in waste catalysts and leaching residues is crucial for their separation and extraction. On the basis of column chromatography separation, this article investigated the leaching rates of V, Na, S, and K in the samples after leaching treatment, which were 95.28%, 98.39%,98.88%, and 97.82%, respectively. SEM showed that the sediment dissolved and disappeared on the surface of the carrier and in the pores. At the same time, the inductively coupled plasma emission spectroscopy (ICP-OES) method was used for determination, and the spectral lines of each element (V 309.311 nm, Na 589.490 nm, K 766.490 nm, S 180.731 nm, Al 394.401 nm, Fe 238.204 nm, As 189.042 nm) were determined. The results showed that the mass concentration of each element was linear with emission intensity within a certain range, and the linear correlation coefficient of the calibration working curve was greater than 0.9999, except for arsenic, which was 0.999 7, The detection limit of each element was 0.004-0.017 µg/g, and the relative deviation (RSD,n=11) of the determination results excluding As was 2.2%. The other elements were less than 0.90%, and the recovery of the added standard was between 98. 9% and 102%. The accuracy and precision of the method can meet the requirements for testing various elements in industrial sulfuric acid waste catalysts, providing data reference for the content of each element in the leaching and separation process of waste catalysts. [ABSTRACT FROM AUTHOR]

Nanoscale materials often undergo structural, morphological, or chemical changes, especially in solution processes, where heterogeneity and defects may significantly impact the transformation pathways. Liquid phase transmission electron microscopy (TEM), allowing us to track dynamic transformations of individual nanoparticles, has become a powerful platform to reveal nanoscale materials transformation pathways and address challenging issues that are hard to approach by other methods. With the development of modern liquid cells, implementing advanced imaging and image analysis methods, and strategically exploring diverse systems, significant advances have been made in liquid phase TEM, including improved high-resolution imaging through liquids at the atomic level and remarkable capabilities in handling complex systems and reactions. In the past more than a decade, we spent much effort in developing and applying liquid phase TEM to elucidate how atomic level heterogeneity and defects impact various physicochemical processes in liquids, such as growth, self-assembly of nanoparticles, etching/corrosion, electrodeposition of alkali metals, catalyst restructuring during reactions, and so on. This article provides a brief review of the liquid phase TEM study of nanoscale materials transformations, focusing on the growth of nanomaterials with distinct shape/hierarchical structures, such as one-dimensional (1D) growth by nanoparticle attachment, two-dimensional (2D) growth with nanoparticles as intermediates, core-shell structure ripening, solid-liquid interfaces including those in batteries and electrocatalysis, highlighting the impacts of heterogeneity and defects on broad nanoscale transformation pathways. [ABSTRACT FROM AUTHOR]

A series of titanium μ2‐nitrido complexes supported by the triamidoamine ligand Xy‐N3N (Xy‐N3N={(3,5‐Me2C6H3)NCH2CH2}3N3−) is reported. The titanium azido complex [(Xy‐N3N)TiN3] (1‐N3), prepared by salt metathesis of the chloride complex [(Xy‐N3N)TiCl] (1‐Cl) with NaN3, reacted with lithium metal or with alkali metal naphthalenides (alkali metal M=Na, K, and Rb) in THF to give the corresponding dinuclear μ2‐nitrido complexes M[(Xy‐N3N)Ti=N‐Ti(Xy‐N3N)] (2‐M; M=Li, Na, K, Rb). Single crystal X‐ray diffraction studies of 2‐Li, 2‐Na, and 2‐K revealed alkali metal dependent structures in the solid state. While 2‐Li and 2‐K contain a μ2‐nitrido ligand with a linear Ti−N−Ti core, 2‐Na includes a μ3‐nitrido ligand as part of a T‐shape Ti2NaN fragment with the sodium cation weekly coordinated to the nitrido nitrogen atom. When the synthesis of the nitrido complexes was carried out in the presence of excess alkali metals, decomposition of the nitrido complexes was observed affording some intractable titanium species along with the trialkali metal salts [M3(Xy‐N3N)] (3‐M) (M=Li, Na, K, and Rb). These salts were also prepared by deprotonation of (Xy‐N3N)H3 with the corresponding alkali metal hexamethyldisilazide and characterized by multinuclear NMR spectroscopy as well as single crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

Birch reactions employing alkali metals in ammonia have been a well‐established method for the reduction and functionalisation of aromatic compounds for nearly 100 years. Speculations regarding intermediates in the reaction pathway have been discussed since the beginning. We hereby report the isolation of NMe4(HNaph) (1), a kinetically trapped intermediate of the Birch reaction of naphthalene and sodium in liquid ammonia. 1 has been fully characterised and has been shown to continue to react to 1,2/1,4‐dihydronaphthalene – the Birch product of the reduction of naphthalene. The reactivity of 1 was investigated towards activity as an electron and hydride transfer agent with both, elements and small organic molecules. 1 demonstrates a tamed reduction potential which allows for controlled reactions such as the selective formation of hexasulphide and hexaselenide anions. [ABSTRACT FROM AUTHOR]

Effectively suppressing nonradiative recombination at the SnO2/perovskite interface is imperative for perovskite solar cells. Although the capabilities of alkali salts at the SnO2/perovskite interface have been acknowledged, the effects and optimal selection of alkali metal cations remain poorly understood. Herein, a novel approach for obtaining the optimal alkali metal cation (A‐cation) at the interface is investigated by comparatively analyzing different alkali carbonates (A2CO3; Li2CO3, Na2CO3, K2CO3, Rb2CO3, and Cs2CO3). Theoretical calculations demonstrate that A2CO3 coordinates with undercoordinated Sn and O on the surface, effectively mitigating oxygen vacancy (VO) defects with increasing A‐cation size, whereas Cs2CO3 exhibits diminished preferability owing to enhanced steric hindrance. The experimental results highlight the crucial role of Rb2CO3 in actively passivating VO defects, forming a robust bond with SnO2, and facilitating Rb+ diffusion into the perovskite layer, thereby enhancing charge extraction, alleviating deep‐level trap states and structural distortion in the perovskite film, and significantly suppressing nonradiative recombination. X‐ray absorption spectroscopy analyses further reveal the effect of Rb2CO3 on the local structure of the perovskite film. Consequently, a Rb2CO3‐treated device with aperture area of 0.14 cm2 achieves a notable efficiency of 22.10%, showing improved stability compared to the 20.11% achieved for the control device. [ABSTRACT FROM AUTHOR]

In this work, we comprehensively studied the cathodic corrosion of Au electrodes as a function of the identity of alkali metal hydroxides at different concentrations and various negative potentials. We reveal that the ratio of free water and water bound in hydration shells controls the overall cathodic corrosion behavior, alongside the specific adsorption of alkali metal cations. Moreover, we highlight the crucial role of electrolyte cleanliness, particularly regarding the presence of trace metal impurities. Interestingly, the presence of trace amounts of nickel and iron in as‐received CsOH suppresses cathodic corrosion by their deposition onto Au surfaces. In contrast, after purification the polarization of Au surfaces in 10 M CsOH leads to the formation of nanoporous surfaces with high electrochemically active surface area, in which the degree of porosity can be tuned by varying the polarization time at −1.6 V vs. RHE. [ABSTRACT FROM AUTHOR]

Tuning the selectivity of CO2 electroreduction reaction (CO2RR) solely by changing electrolyte is a very attractive topic. In this study, we conducted CO2RR in different aqueous electrolytes over bulk metal electrodes. It was discovered that controlled CO2RR could be achieved by modulating cations in the electrochemical double layer. Specifically, ionic liquid cations in the electrolyte significantly inhibits the hydrogen evolution reaction (HER), while yielding high Faraday efficiencies toward CO (FECO) or formate (FEformate) depending on the alkali metal cations. For example, the product could be switched from CO (FECO=97.3 %) to formate (FEformate=93.5 %) by changing the electrolyte from 0.1 M KBr‐0.5 M 1‐octyl‐3‐methylimidazolium bromide (OmimBr) to 0.1 M CsBr‐0.5 M OmimBr aqueous solutions over pristine Cu foil electrode. In situ spectroscopy and theoretical calculations reveal that the ordered structure generated by the assembly of Omim+ under an applied negative potential alters the hydrogen bonding structure of the interfacial water, thereby inhibiting the HER. The difference in selectivity in the presence of different cations is attributed to the hydrogen bonding effect caused by Omim+, which alters the solvated structure of the alkali metal cations and thus affects the stabilization of intermediates of different pathways. [ABSTRACT FROM AUTHOR]

Metal chalcogenides, as a new class of semiconductor materials, have a broad range of applications in synthetic chemistry due to their rich structures and excellent properties. We have synthesized two selenoantimonates A4Zn2Sb2Se7 [A = Rb(1), Cs(2)] under solvothermal conditions in the visible region using a band gap optimization strategy with alkali metals as structure-directing agents. Compounds 1 and 2 have a two-dimensional layered structure consisting of charge-balanced Rb+(1) or Cs+ (2) cations and [Zn2Sb2Se7]4- anions with novel 20-membered rings (20-MR) [Zn6Sb4Se10] with an aperture of 5.6949 × 13.7741 Ų formed in the middle. Furthermore, we have investigated the crystal structure, band gap, photoelectronic properties, and energy band structure. [ABSTRACT FROM AUTHOR]

The transition metal properties of heavy alkaline earth metals have been extensively studied, and their neighbouring heavy alkali metals have been limited to the interactions with CO‐σ ligands. Based on this, the complexes [K2M(COT)2]− (M=K, Rb, Cs) interacting with heavy alkali metals and COT‐π ligands are theoretically designed in this paper. The electronic structure analysis showed that the three complexes had 10 occupied molecular orbitals (MOs), in which 8 of them were related to the atomic orbitals (AOs) of central alkali metals, including 4 d orbitals (dxy, dx2−y2, dxz, dyz), so they also exhibited the typical behaviors of transition metals. NBO analysis indicated that the central metals in these complexes are common valence of +1, the ligands are negative, so the electrostatic coulomb interaction between positive and negative ions makes them more stable. This can be reflected by the high binding energies of −585.8 to −594.0 kcal/mol, which are much higher than those of −6.5 to −63.3 kcal/mol for the trace amount of complexes combined by neutral metals and ligands. It would be a feasible strategy for the design of the macrosynthesis of related complexes by combining the positive ions and negative ligands, which can stabilize the complexes through the favorable Coulomb attractions. [ABSTRACT FROM AUTHOR]

The potential for decorating single Li, Na, or K atoms onto BeS monolayers and their subsequent hydrogen storage performance were investigated using first-principle density functional theory (DFT) calculations. The single-atom Li, Na, or K exhibited strong adhesion to the BeS monolayer, with binding energies of −2.662 eV, −1.982 eV, or −1.669 eV, respectively. Each Li or Na atom on BeS demonstrated the ability to capture four H 2 molecules, while a single K atom could bind only three H 2 molecules. Notably, Li exhibited stronger binding with stored H 2 compared to Na or K. Moreover, by increasing the number of Li atoms on each side of the BeS monolayer to nine, the storage of H 2 molecules was improved to a total of 54, concomitant with an advantageous average adsorption energy of −0.236 eV. This enhancement resulted in a significant increase in the hydrogen storage capacity to 6.514 wt%. Molecular dynamics simulations indicated a desorption temperature of approximately 450 K, with the 18 Li atoms remaining strongly bonded to the BeS due to their high diffusion energy of 0.578 eV. Thus, the Li-decorated BeS monolayer emerges as a promising substrate for achieving exceptional and reversible hydrogen storage performance. • Alkali-metal atom (Li, Na, or K) could be well dispersed on the BeS monolayer. • Li atom shows a stronger adsorption strength to H 2 molecules than Na or K. • 18 Li atoms on BeS can capture 54H 2 with an ideal E adsav of −0.236 eV. • Li atoms remain dispersed on BeS even at desorption temperature of the 54H 2. • Li-decorated BeS demonstrates a high hydrogen storage capacity of 6.514 wt%. [ABSTRACT FROM AUTHOR]

During the operation of the waste liquid incinerator, the alkali metal slag might adhere to the surface of the refractory material to form an inhomogeneous solid slag layer, causing the furnace lining to be simultaneously corroded by three phases of alkali metals: vapor, molten salt, and slag. This phenomenon intensifies the damage to the refractory material. Therefore, this paper investigates the mass transfer and permeation process, phase change process and corrosion rate of Na 2 CO 3 inside corundum refractory materials in three phases: Na vapor, molten Na 2 CO 3 and Na-slag. The results showed that alkali vapor penetrated the interior through the pores, and the NaAlO 2 and β-Al 2 O 3 generated by the reaction led to the volume expansion and microcracks. Na vapor continued to penetrate the interior along the cracks and eroded the sample, and the higher the temperature the greater Na vapor penetration. In vapor phase corrosion, the effect of corrosion time on the erosion resistance of corundum refractories is less than that of temperature, and the increase in corrosion time does not lead to the formation of additional new phases. In the molten salt corrosion experiments, it was found that the molten salt corrosion was accompanied by vapor phase corrosion at 1100 °C, and the amount of Na 2 CO 3 has a greater effect on the corroded mass than the temperature. Comparing the corrosion of refractory materials by the three phases of Na 2 CO 3 , the molten salt corrosion rate was the highest, followed by the vapor phase corrosion, and finally the slag corrosion. It is concluded that the slag layer can effectively prevent the corrosion of the refractory material by alkali metal molten salts and vapors, thus prolonging the service life of refractories. [ABSTRACT FROM AUTHOR]

The solid‐state structures of the first rubidium and caesium pentalenides [Rb(THF)]2[Ph4Pn] and [Cs(THF)]2[Ph4Pn] have been determined by single crystal X‐ray diffraction. Both were found to be polymeric in the solid state through interactions of the cations with the phenyl substituents, in contrast to their lighter group 1 congeners which are monomeric for lithium and sodium, and THF‐bridged for potassium. Both [Rb(THF)]2[Ph4Pn] and [Cs(THF)]2[Ph4Pn] displayed increased η8 coordination, demonstrating a shift towards higher hapticities down the group as previously predicted computationally for the parent M2[Pn] complexes (M=group 1 metal). The solid‐state structures of the polydentate donor adducts [M(DME)x]2[Ph4Pn] (M=Li, x=1; M=Na, x=2) and [M(Me6TREN)]2[Ph4Pn] (M=K, Rb, Cs) were all monomeric and displayed increased metal‐carbon distances and decreased ring slippage values relative to the THF adducts. [ABSTRACT FROM AUTHOR]

The document is the contents list for the journal "Chemical Communications" published on September 14, 2024. It includes highlights, feature articles, and communications on various topics in chemistry. Some of the topics covered include transition metal complexes, electrochemical biosensors, and photochemical catalysis. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

Chemical reduction of a vertically expanded pentacene, TIPS-peri-pentacenopentacene (TIPS-PPP), with sodium metal in THF readily afforded a doubly-reduced product isolated as [{Na+(THF)3}2(TIPS-PPP2−)]. Single-crystal X-ray diffraction revealed the formation of a π-complex of TIPS-PPP2− with two {Na+(THF)3} moieties. The sodium ion is coordinated to three C-atoms at the most negatively charged edge sites and at the lateral ethynyl group. The delocalisation of the charge on the ethynyl function is accompanied by its notable elongation (Δ = 0.015 Å) coupled with the contraction of the adjacent single C–C bond (Δ = 0.033 Å). Bond length analysis supported by Harmonic Aromaticity Oscillator Model (HOMA) shows that the dianion can be written with four aromatic sextets in agreement with the Clar representation. Although TIPS-PPP2− has 36 π-electrons (4n), it does not show a global magnetic paratropic response. The rings with the most negative charge density have a very low paratropic response, while the other rings have a low diatropic response. Overall, the dianion is a non-aromatic molecule. [ABSTRACT FROM AUTHOR]

A facile room-temperature synthetic method is presented to produce alkali metal salts of tert-butyl phosphonic acid. The reaction between equimolar amounts of alkali metal carbonates and tert-butyl phosphonic acid in methanol results in the formation of [(tBuPO3H)Li(H2O)3•(H2O)] (1), [(tBuPO3)Na2(H2O)4]n (2), and [(tBuPO3H)K(H2O)]n (3). Solid-state structures of these compounds have been confirmed by single-crystal X-ray diffraction studies and further validated using numerous spectroscopic and analytical techniques. Compounds 1--3 are polymeric solids that are predominantly made up of a 1-D polymeric metal phosphonate chain. This synthetic approach leads to the formation of network structures/polymers in the solid state that otherwise are absent in solution due to the ionic nature of the interaction between the alkali metal ions and phosphonate anions. Apart from the multidentate nature of the phosphonate ligands, additional hydrogen bonding interactions involving water molecules, free P--OH groups, and P O moieties allow these chains to be propagated into 2-D sheets. We have further utilized the completely metalated sodium phosphonate 2 to synthesize layered metal phosphonates [(tBuPO3)Ca(H2O)]n (4), [(tBuPO3)Mn(H2O)]n (5) and [(tBuPO3)Co(H2O)]n (6) via a simple metathesis reaction. [ABSTRACT FROM AUTHOR]

In this work, we predict a new two-dimensional metallic carbon-boron material, named Me–C 8 B 5 , which is composed of octagons, pentagons and hexagons. By DFT calculation, we examine the efficacy of hydrogen storage in alkali and alkaline-earth metals modified Me–C 8 B 5 structures. Our findings reveal that these metals exhibit a robust affinity for the Me–C 8 B 5 substrate, characterized by substantial binding energies, thereby mitigating the tendency to form clusters. In particular, the hydrogen storage capacity for Li, Na, Mg and Ca modified Me–C 8 B 5 reach 6.87 wt%, 7.60 wt% and 5.74 wt% and 9.51 wt%, respectively, higher than the DOE requirement of 4.5 wt%. The results of relative energy reveal that the Li-modified system exhibits more appropriate pressure (8.4 bar) and temperature (370 K) for maintaining stable hydrogen storage. Notably, the suitable average desorption temperatures coupled with the stability exhibited in AIMD simulations indicate that Me–C 8 B 5 scaffolds modified with metals Li, Na, Mg, and Ca may possess viable practical applications in the realm of reversible hydrogen storage. These outcomes are anticipated to stimulate the pursuit and continued refinement of novel, superior two-dimensional materials for hydrogen storage. [Display omitted] • Me–C 8 B 5 : A new two-dimensional metallic carbon-boron material. • Using DFT, H 2 storage in alkali and alkaline earth metal decorated Me–C 8 B 5 is reported. • Ca decorated Me–C 8 B 5 possesses ultrahigh gravimetric H 2 uptake (9.51 wt%). • The stability of adsorption systems is proved by ab-initio MD simulations. [ABSTRACT FROM AUTHOR]

Water structures at electrolyte/electrode interfaces play a crucial role in determining the selectivity and kinetics of electrochemical reactions. Despite extensive experimental and theoretical efforts, atomic-level details of ion-specific water structures on metal surfaces remain unclear. Here we show, using scanning tunneling microscopy and noncontact atomic force microscopy, that we can visualize water layers containing alkali metal cations on a charged Au(111) surface with atomic resolution. Our results reveal that Li+ cations are elevated from the surface, facilitating the formation of an ice-like water layer between the Li+ cations and the surface. In contrast, K+ and Cs+ cations are in direct contact with the surface. We observe that the water network structure transitions from a hexagonal arrangement with Li+ to a distorted hydrogen-bonding configuration with Cs+. These observations are consistent with surface-enhanced infrared absorption spectroscopy data and suggest that alkali metal cations significantly impact hydrogen evolution reaction kinetics and efficiency. Our findings provide insights into ion-specific water structures on metal surfaces and underscore the critical role of spectator ions in electrochemical processes. Water structures at the electrolyte and electrode interfaces are crucial for electrochemical reactions. Here, the authors report that alkali metal cations can modify two-dimensional water networks at charged surfaces, impacting both reaction kinetics and efficiency. [ABSTRACT FROM AUTHOR]

The catalytic application of chiral phosphoric acids (CPAs) from 2004 to date represents a true milestone for asymmetric organocatalysis. However, not only the free acids can be conveniently employed in numerous different asymmetric synthetic methodologies, thus being strictly compliant to the concept of "organocatalysis", but also their metal salts. This review focuses on asymmetric reactions in which the catalyst is a chiral alkali or alkaline‐earth metal phosphate. [ABSTRACT FROM AUTHOR]

Ammonia decomposition to H2 (ADH) is one of the key reactions in the ammonia‐based energy system. Recent research has been focused on developing more active and affordable catalysts, however, few can operate below 500 °C and typically require the expensive metal ruthenium. Herein, a fundamentally different thermal ADH via a chemical looping process (CLADH) mediated by alkali metal and its amide pairs, which can work under lower temperatures than the catalytic process, is reported. This CLADH consists of two steps: 1) Ammoniation step ̶ NH3 reacts with Na or K to generate NaNH2 or KNH2, respectively, accompanied by releasing one‐third of H2 in NH3 at room temperature; 2) Decomposition step ̶ NaNH2 or KNH2 decomposes to N2 and H2 with the regeneration of Na or K which can be performed above 275 °C. Additionally, due to the significant enthalpy change in the two‐step reactions of this CLADH, −78.0 kJ mol−1 for the first step and 123.9 kJ mol−1 for the second, using the Na and NaNH2 pair—suggest potential for thermal energy storage. This work not only reports an alternative route to produce H2 from NH3, but also unravels the potential of chemical looping process for thermal energy storage. [ABSTRACT FROM AUTHOR]

Layered honeycomb iridates receive significant attention in the materials chemistry and physics fields due to the relevance of their crystal structures to the Kitaev model of a quantum spin liquid (QSL). In quest of liquid‐like magnetic ground state signatures, first‐generation alkali metal iridates A2IrO3 ≡ A3[AIr2]O6 (A = Li, Na) and second‐generation iridates T3[AIr2]O6 (T = Cu, Ag, H) are developed. T3[AIr2]O6 is synthesized from A3[AIr2]O6 via metathesis reactions replacing alkali ions located between honeycomb layers. Herein, the next level of chemical and structural complexity is introduced by synthesizing the honeycomb iridate, Cu3ZnIr2O6, in which alkali ions between and within the honeycomb layers are both selectively exchanged with two different transition metals. Analysis of powder X‐Ray diffraction data reveals corrugation of the honeycomb layers in Cu3ZnIr2O6 that hinders complete magnetic frustration and results in a spin glass behavior observed from magnetization and specific heat data. Thus, Cu3ZnIr2O6 represents yet another model, which broadens understanding of intricate relationships between intralayer distortions and magnetism of prospective Kitaev QSL compounds. [ABSTRACT FROM AUTHOR]

The structural flexibility of the perovskite blocks in the Dion-Jacobson family of layered perovskite oxides has successfully resulted in the generation of KPrNa n-2 Nb n O 3n+1 and KPrCa n-2 Nb 2 Ti n-2 O 3n+1 (n = 3, 4). The stabilization of K+ ions preferring a six coordination in the interlayer region is significant compared to the facile formation of layered perovskite oxides possessing bigger Rb+ or Cs+ ions with an eight coordination in the interlayer. The structure of the n = 3 members, KPrNaNb 3 O 10 (S. G. Cmcm ; a = 3.8858(1) Å, b = 29.6553(9) Å, c = 7.7635(3) Å) and KPrCaNb 2 TiO 10 (S. G. Cmcm ; a = 3.8634(2) Å, b = 29.4808(2) Å, c = 7.6945(5) Å) were confirmed respectively using the Rietveld and Le Bail methods utilizing the powder X-ray diffraction data. The n = 4 members, KPrNa 2 Nb 4 O 13 and KPrCa 2 Nb 2 Ti 2 O 13 are synthesized through high-temperature ceramic methods. The compounds are phase pure as confirmed from the X-ray diffraction data and were characterized by UV–visible diffuse reflectance measurements. These two-dimensional oxides also undergo facile topochemical ion-exchange and intercalation reactions and opens up several interesting possibilities. We have replaced the K+ ions in the interlayer by H+, Li+, Na+ ions and [CuCl]+ groups through low temperature reactions. The usefulness of various Dion-Jacobson layered perovskite oxides for potential photocatalytic applications has been explored by determining the optical band gaps, the valence band, and the conduction band energy levels based on the UV–visible diffuse reflectance measurements. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction reaction (NO3RR) is a process that requires the participation of eight electrons and nine protons. The regulation of active hydrogen (H*) supply and a deep understanding of related processes are necessary for improving the ammonia yield rate and Faradaic efficiency (FE). Herein, we synthesized a series of atomically precise copper‐halide clusters Cu2X2(BINAP)2 (X=Cl, Br, I), among which the Cu2Cl2(BINAP)2 cluster shows the optimal ammonia FE of 94.0 % and an ammonia yield rate of 373 μmol h−1 cm−2. In situ experiments and theoretical calculations reveal that halogen atoms, especially Cl in Cu2Cl2(BIANP)2, can significantly affect the distance of alkali metal‐ionized water on the catalyst surface, which can promote the water dissociation to enhance the localized H* enrichment for the continues hydrogenation of nitrate to ammonia. This work explains the role of H* in the hydrogenation process of NO3RR and the importance of localized H* enrichment strategy for improving the FEs. [ABSTRACT FROM AUTHOR]

For the first time potassium single-atoms (K SA) are explored as the sensing material to boost electrochemical sensing of hydrogen peroxide (H2O2). The N-doped carbon material with a three-dimensional porous structure (3D NG) was prepared using NaCl as the template, and K SA were anchored to the surface of 3D NG through high-temperature pyrolysis. The structure of K SA/3D NG was characterized by TEM, HAADF-STEM, XPS, and XRD. The results of electrochemical studies indicate that K SA play a crucial role in promoting the electrocatalytic reduction of H2O2, which not only optimized the adsorption strength for H2O2 but also improved the electron transfer rate, therefore improving the sensitivity for detecting H2O2. This study demonstrates the excellent electrocatalytic activity of K SA, which provides a promising sensing material for the detection of H2O2 and lays the foundation for the application of alkali metal single-atoms in the field of electrochemical sensing. [ABSTRACT FROM AUTHOR]

Radiative cooling pigments offer new opportunities for sustainable carbon neutrality as zero‐energy and zero‐pollution functional materials. However, it is a challenge to prepare inorganic yellow pigments simultaneously with environmentally friendly, high color value, and weather resistance. In this study, a series of alkali metal‐doped γ‐Sm2S3 yellow pigments with near‐infrared reflectance were synthesized. The doping of alkali metal ions reduced synthesis temperature of Sm2S3 from 1300°C to 1000°C. The change in energy band structure induced by alkali metal doping allows the products to exhibit modifiable colors. Typical γ‐[Na]‐Sm2S3 pigment powders have a high near‐infrared reflectance and impressive colors (b* = 78.6, C* = 77.6). Furthermore, colored films made by prepared yellow powders with polyvinylidene fluoride in certain ratios had high near‐infrared reflectance and excellent environmental weathering, resulting in an effective cooling of 4–8°C in outdoor experiments. This work expands the range of options for energy‐efficient building and yellow colorant. [ABSTRACT FROM AUTHOR]

The distribution of rare alkalis (Li, Rb, and Cs) is analyzed in spatially linked water objects of the Baikal geosystem: water of Baikal and its tributaries, underground water from boreholes and thermal springs, and the Angara River (the sole outlet), which are located in the Baikal rift zone. The rare alkali content differs significantly in some water objects, but the average and median contents are similar in the surface and deep water of Lake Baikal and the Angara River. The water of Barguzin thermal springs of the eastern shore of Lake Baikal contains the maximum amount of rare alkalis, but this affects the Baikal water insignificantly due to its natural self-cleaning and deep renewal of water during geodynamic movements. The similar rare alkali contents of Barguzin and some thermal springs of Kamchatka emphasize their indicator role in the genesis of water objects. [ABSTRACT FROM AUTHOR]

Leucites are tetrahedrally coordinated silicate framework structures with some of the silicon framework cations that are partially replaced by divalent or trivalent cations. These structures have general formulae A 2 B Si5O12 and AC Si2O6, where A is a monovalent alkali metal cation, B is a divalent cation, and C is a trivalent cation. There are also leucite analogs with analogous tetrahedrally coordinated germanate framework structures. These have general formulae A 2 B Ge5O12 and AC Ge2O6. In this paper, the Rietveld refinements of three synthetic Ge-leucite analogs with stoichiometries of A AlGe2O6 (A = K, Rb, Cs) are discussed. KAlGe2O6 is I 41 /a tetragonal and is isostructural with KAlSi2O6. RbAlGe2O6 and CsAlGe2O6 are $I\bar{4}3d$ cubic and are isostructural with KBSi2O6. [ABSTRACT FROM AUTHOR]

Organometallic complexes containing reactive alkali metals, such as lithium (Li), represent a promising material approach for electron injection layers and electron transport layers (EILs and ETLs) to enhance the performance of Organic Light-Emitting Diodes (OLEDs). 8-Quinolinolato Lithium (Liq) has shown remarkable potential as an EIL and ETL when conveyed in very thin films. Nevertheless, the deposition of nano-layers requires precise control over both thickness and morphology. In this work, we investigate the optical properties and morphological characteristics of Liq thin films deposited via Organic Vapor Phase Deposition (OVPD). Specifically, we present our methodology for analyzing the measured pseudodielectric function <ε(ω)> using Spectroscopic Ellipsometry (SE), alongside the nano-topography of evaporated Liq nano-layers using Atomic Force Microscopy (AFM). This information can contribute to the understanding of the functionality of this material, since ultra-thin Liq interlayers can significantly increase the operational stability of OLED architectures. [ABSTRACT FROM AUTHOR]