We present a systematic first-principles study of ANiO 3 perovskites (A = Li, Na, K, Rb, Be, Mg, Ca, Sr, Ba) to elucidate how A-site substitution governs their structural, electronic, and optical properties. Using hybrid density functional theory (PBE 0 and HSE 06 ), we evaluate lattice stability, band structures, density of states, and frequency-dependent optical functions, including absorption, reflectivity, refractive index, extinction coefficient, and energy loss spectra. Results reveal a progression from metallic or semimetallic behavior in LiNiO 3 , RbNiO 3 , and BeNiO 3 to wide-gap insulating states in SrNiO 3 and BaNiO 3 . PBE 0 consistently predicts larger bandgaps and closer agreement with experimental benchmarks compared to HSE 06 . Optical responses strongly correlate with electronic structure: alkali compounds display low-energy absorption and plasmonic peaks, while alkaline earth members show enhanced UV absorption and high dielectric response. These findings highlight A-site chemistry as an effective strategy for tailoring nickelate perovskites for optoelectronic, photonic, and energy-conversion applications. • First-principles DFT study of ANiO 3 perovskites with alkali and alkaline earth cations • Comparative electronic and optical properties analyzed using PBE0 and HSE06 functionals • Bandgap magnitude and character strongly depend on A-site substitution chemistry • Alkali perovskites show low-energy absorption and plasmonic features • Alkaline earth perovskites exhibit enhanced UV absorption and dielectric response

Surface properties of liquid alkali and alkaline earth metals: A theoretical and simulation approach

Tailoring electrocatalytic performance for ORR of medium-entropy Ruddlesden-Popper type electrode through rational ionic potential design.

Investigation of the alkali metal anti-poisoning performance of modified VW/Ce-Ti catalyst in NH3-SCR reaction

Alkali metal migration and slagging prediction model during co-firing of high-silica/alumina lignite and corn stover

Synergetic interlayer effects in MoS₂/GeC van der Waals heterostructures: Toward universal high-performance anodes for alkali metal ion batteries

Pressure induces the structural stability, mechanical, electronic and optical properties of alkali metal AMH (AM=Li and Na) hydrides for hydrogen storage

Exploiting structural benefit of cyclotetraphosphate for delayed quenching concentration of Eu3+ luminescence and efficiency enhancement via co-doping alkali metal

Effect of flue gas humidity and inherent alkali metal on flue gas torrefaction coupled gasification of Chinese herb residues

• Cation-dependent solvation governs spontaneous ion adsorption in microporous carbons • Na⁺, K⁺, and Cs⁺ salts exhibit distinct concentration-dependent pore accessibility and wettability • Ion pairing and aggregation modulate hydration structure and electrosorption behavior • CsTFA delivers superior charge storage due to enhanced confinement and ionophilicity The performance of energy storage devices is strongly dependent on electrolyte properties and their interaction with porous carbon electrodes. This report presents a detailed discussion of the use of trifluoroacetate (TFA)-based water-in-salt (WIS) electrolytes for supercapacitors. Raman spectroscopy is used to analyse contrasting interactions between group 1 cations and TFA. Nuclear Magnetic Resonance (NMR) spectroscopy further confirms differences in ion confinement, showing that CsTFA exhibited enhanced ion adsorption within carbon nanopores, correlating with its superior charge storage capacitance. Additionally, analysis of NMR data revealed that KTFA displayed lower ion adsorption within micropores compared to NaTFA and CsTFA, suggesting lower ionophilicity and explaining the lower capacitance of the K + salt. These differences are attributed to contrasting solvation behavior of Na⁺ and Cs⁺, where Na⁺ strongly interacts with the carbonyl group of the acetate at lower concentrations, but transitions to direct ion pairing at higher concentrations, whereas Cs⁺ favors ion clustering and weaker coordination across all concentrations. Potential of zero charge (PZC) measurements reinforce these findings, revealing shifts in ion adsorption behavior with increasing electrolyte concentration. Electrochemical analysis demonstrated that 20 m CsTFA achieved the highest capacitance while 10 m CsTFA exhibited the fastest charge transfer and highest energy and power density. Adsorption properties of TFA salts on carbon surfaces are of direct relevant to current fluoro-chemical remediation strategies.

2D materials hold transformative promise for next-generation nanoelectronics. However, successfully integrating these materials from laboratory-scale discoveries into real-world devices depends on precisely controlling their properties, which are fundamentally determined by their composition. Detailed characterisation using atom probe tomography of 2D Ti0.87O2, a candidate high-$κ$ dielectric, reveals deviations from its commonly assumed stoichiometry. Compositional analysis and comparison with the bulk K0.8[Ti1.73Li0.27]O4 precursor evidences an oxygen deficit indicative of oxygen vacancy formation in the 2D material, as well as the retention of low concentrations of alkali metals that were presumed to be removed during synthesis. Such deviations from stoichiometry indicate a reconstruction mechanism that mitigates the effect of the characteristic, negatively charged vacancies on the titanium sublattice, thereby influencing the local electronic structure and, consequently, functional properties. These findings underscore the importance of a detailed compositional analysis in both understanding and optimizing the extraordinary functional properties of 2D materials, opening pathways to tailored functionalities in next-generation nanoelectronics.

Study on structure, properties of alkaline earth boroaluminosilicate sealing glasses and silver electrodes sintering behavior

Spatio-temporal variation in hydrogeochemical characteristics and trace elements occurrence in groundwater in parts of Lakhimpur district, Uttar Pradesh

The oxygen evolution reaction (OER) is key to the operation of various sustainable technologies like water-splitting devices and metal-air batteries. Realization of efficient OER depends on robust electrocatalyst materials as well as optimized electrolytes. The cations in electrolytes have a pronounced impact on the kinetics of OER. However, the mechanistic origin of this effect remains poorly addressed. In this study, using cobalt vanadium oxide Co3V2O8 (CVO) as a model electrocatalyst, the cation-dependent OER activity was investigated using fundamental electrochemical study in conjunction with ex situ (electron microscopy and Raman spectroscopy) analyses. The results demonstrate that OER performance is not only affected by surface/bulk reconstruction, but also governed by electrolyte cation adsorption. In situ Raman study in 1 M KOH electrolyte identified the generation of Co-oxyhydroxide species accompanied by vanadium dissolution, whereas ex situ Raman spectra revealed a more distinct VO bond in catalysts when subjected to 1 M CsOH. While partial amorphization was noticed in LiOH and NaOH systems, structural retention with irregular Co(O)OH domains was observed in CVO after catalysis in KOH and CsOH electrolytes. Electrochemical evaluation further establishes exchange current density as the sole parameter significantly affected due to the presence of different cations, directly correlating with reduced overpotential (320 mV) and extended durability (>12 hr continuous electrolysis). These findings highlight the critical role of electrolyte cations in modulating the intrinsic kinetics of Co3V2O8 toward OER electrocatalysts.

ABSTRACT Zhundong coal has severe slagging and fouling from alkali metals, with sintering being the most critical step in slagging. Co – firing with kaolin is a relatively effective solution to these issues, but the sintering mechanism of kaolin on Zhundong coal ash remains unclear, which limits the optimization of its addition ratio and particle size parameters. In this study, the effects of kaolin particle size and addition ratio on the sintering characteristics of Zhundong coal ash were systematically investigated. The results indicated that as the temperature increased, the area shrinkage rate of ash blocks underwent stages of stabilization, decrease, increase, and rapid decrease. After kaolin was added, the temperature at which the shrinkage rate began to decrease was increased by approximately 100°C compared with that of the raw coal ash. At the sintering temperature, when kaolin with larger particle sizes was added, the ash blocks tended to form an abundant porous structure, thereby reducing the compactness of the ash blocks. The sintering strength of the ash blocks increased with an increase in addition ratio but decreased with an increase in particle size. When the addition ratio of 100–150 µm kaolin reached 3 wt.%, the sintering strength of the ash blocks decreased to 6.15 MPa, a 23.9% reduction compared to that without kaolin. Furthermore, after the addition of kaolin, NaAlSiO4 was detected in all ash samples, which is consistent with the conclusion that kaolin can capture alkali metals in coal ash. Finally, the influence mechanism of kaolin on the sintering process of Zhundong coal ash was proposed.

Replacing conventional transition metals with main-group elements for chemical bond activation and catalysis is of increasing interest, yet alkali metals remain largely underexplored in this context. Herein, we introduce a new strategy for alkali metal-mediated catalysis based on metal-ligand cooperation (MLC) driven by dearomatization-aromatization of the ligand. Potassium pincer complexes bearing dearomatized picolyl ligands were synthesized and shown to activate a variety of molecules, including CO2, CS2, phenyl iso(thio)cyanates, ketones, and H2, thereby enabling the design of alkali metal catalysis. Notably, a dearomatized potassium complex efficiently catalyzed the hydrogenation of ketones and C─C multiple bonds, reactions that remain challenging in alkali metal catalysis. Density functional theory (DFT) calculations elucidated the electronic structures and bonding characteristics of the obtained complexes and provided mechanistic insight into the transformations. This work establishes a new paradigm in alkali metal chemistry and broadens the scope of MLC for bond activation and catalysis.

Nonlinear optical (NLO) crystals with transparency extending into the deep-ultraviolet (DUV) region have received intense research interest. However, designing DUV NLO crystals with well-balanced comprehensive performance remains challenging. Here, we report a new mixed alkali and alkaline-earth metal polyborate NLO crystal, LiCaB9O15 (LCBO), synthesized via spontaneous nucleation. LCBO belongs to the chiral orthorhombic space group P212121 (No. 19) and features a three-dimensional framework formed by the spiral alignment of [B3O7] groups. This unique structure results in a deep-UV cutoff edge below 200 nm with a large bandgap of 5.7 eV. Moreover, LCBO exhibits a moderate second-harmonic generation response (SHG) of 0.8 × KDP and a suitable birefringence of 0.033 at 1064 nm. First-principles calculations trace the optical characteristics of LCBO primarily to the B-O sp hybrid orbitals in [B3O7] groups. The combination of these properties positions LCBO as a potential candidate for short-wave UV NLO applications and contributes to the expanding structural diversity in metal polyborate chemistry.

Two-dimensional (2D) inorganic materials provide a powerful platform for electronic-structure engineering through precise control of the composition and crystal structure. While cation substitution has been widely exploited in oxide nanosheets, anion engineering remains far less developed, particularly in molecularly thin oxynitride systems with controlled nitrogen doping. Here, we report a generalizable route to nitrogen-doped perovskite oxide nanosheets that overcomes long-standing challenges associated with nitridation and structural instability. Using Dion-Jacobson (DJ)-type perovskite oxynitrides, RbSr2(Nb1-xTax)3O10-yNy, as a model platform, we demonstrate that the combination of cation substitution and nitrogen doping enables systematic modulation of both composition and electronic band structure in 2D perovskites. DJ-type perovskite oxynitrides with substantial nitrogen incorporation can be obtained via an unexpected transformation from pseudo-Ruddlesden-Popper-type phases, induced by alkali metal salt-assisted nitridation followed by simple aqueous treatment, without altering the anion composition. These oxynitrides are subsequently exfoliated into single-layer nanosheets that preserve the perovskite framework and the designed cation stoichiometry. Direct determination of both valence and conduction band edges by combined ultraviolet and inverse photoelectron spectroscopy reveals composition-dependent, nonmonotonic band alignment behavior that cannot be resolved by indirect optical or electrochemical approaches. This work establishes an integrated materials and characterization framework for the rational electronic-structure design in 2D oxynitride nanosheets.

The strategic selection of alkali metal nitrates in molten salt synthesis critically governs the structural evolution and electrocatalytic performance of iridium oxide hydrate (IrOx·nH2O) catalysts for oxygen evolution reaction (OER). While NaNO3-mediated synthesis has shown superior catalytic activity, we systematically investigated LiNO3 and KNO3 as alternative molten salt media to elucidate structure-property relationships. X-ray pair distribution function (PDF) analysis revealed that the LiNO3-derived catalysts retained a significant amount of unreacted amorphous IrCl3 precursor, yielding the poorest electrocatalytic efficiency. This incomplete conversion is attributed to the exceptionally high viscosity of molten LiNO3, which severely restricts precursor diffusion and crystal growth. In contrast, KNO3-mediated synthesis produced a local structure that can be described as a mixture of hollandite- and rutile-type motifs, delivering intermediate performance. The emergence of rutile-type IrO6 octahedral connectivity due to localized thermal hotspots arising from the lower thermal conductivity of molten KNO3 relative to NaNO3 promotes temperature-induced phase transformations. These findings establish a fundamental correlation between the physicochemical properties of molten salts and catalyst architecture, demonstrating that NaNO3-facilitated hollandite-type local structures optimize ion transport pathways and electrocatalytic activity. This work highlights the critical importance of rational molten salt selection in the design of high-performance OER catalysts.

How additives steer sewage sludge hydrochar properties: Divergent pathways of MgO/CaO versus sawdust in carbon/nutrient fate and magnetism.