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As reported during the last five years, SnSe is one of the leading thermoelectric (TE) materials with a very low lattice thermal conductivity. However, its elements are not as heavy as those of classical thermoelectric materials like PbTe or Bi2Te3. Its outstanding TE properties were revealed after repeated purification steps to minimize the amount of oxygen contamination, followed by spark plasma sintering. Recently, we showed that hot-pressing—once optimized—can yield comparable or even better TE performance using the examples of Na- and Cu- as well as Na- and Ag-co-doped SnSe. However, long-term stability remains a challenge during cycling between low and high temperatures. Here, we investigated whether the cooling procedure has a significant impact on the thermoelectric properties of SnSe. We compared cooling of the melt with a 1:1 ratio of Sn:Se from 1273 K down to room temperature in air with quenching in water. As typical for undoped SnSe, both materials were extrinsic p-type semiconductors due to Sn defects. The air-quenched sample exhibited higher thermal conductivity, lower electrical conductivity, and higher Seebeck coefficient, all consistent with a smaller number of defects and thus a smaller number of charge carriers due to the slower cooling procedure. This resulted in a comparatively low peak figure-of-merit value zT of 0.61 at 823 K for the air-quenched sample, compared to the substantially higher peak zT of 1.58 at 813 K for the water-quenched sample. [ABSTRACT FROM AUTHOR]

Alkaline water electrolysis is a promising avenue for hydrogen and oxygen production. Yet, the pursuit of highly efficient nonprecious electrocatalysts to drive the hydrogen evolution reaction and oxygen evolution reaction persists as a formidable obstacle. Herein, we present a viable method for constructing a catalyst utilizing distinct interfacial interfaces. Within this catalyst, NiSe2 and FeSe2 are anchored onto NiCo-LDH nanosheets, potentially enhancing the inherent properties of the catalyst and demonstrating remarkable performance across various aspects of water electrolysis. Specifically, it exhibits impressive efficiency in both the OER and HER, displaying overpotentials of 256 and 176 mV, respectively, at 50 mA cm–2. Moreover, it promotes complete splitting of water, achieving 50 mA cm–2 at a potential of 1.63 V under alkaline conditions. Additionally, the NiCo-LDH/FeSe2/NiSe2 catalyst showcases notable attributes such as a substantial electrochemically active surface area and prolonged stability. Given the reported performance, this research provides valuable perspectives on the contributions of multiphase materials to the advancement of water electrolysis technology. [ABSTRACT FROM AUTHOR]

In this paper, pod-like Fe7Se8/C nanocomposite catalyst materials were prepared by MIL-88 selenide annealing and the as-prepared Fe7Se8/C nanocatalyst exhibited excellent electrocatalytic performance in neutral electrolyte for the electrocatalytic nitrogen reduction reaction (eNRR). The average ammonia yield rate was 7.11 μg h−1 mgcat−1 with a corresponding faradaic efficiency (FE) of 10.44% obtained at the optimum potential of −0.3 V. Moreover, the as-prepared Fe7Se8/C electrocatalyst shows good selectivity and stability for the eNRR. [ABSTRACT FROM AUTHOR]

Local charge modulation is an effective method to improve the polarization loss and electromagnetic (EM) absorption characteristics. However, the use of conventional means (doping, defects, heterojunction surfaces) remains singular and limited in achieving local charge modulation. Surprisingly, lattice distortions induced by high‐entropy engineering can intrinsically regulate local charge states and improve EM wave absorption performances. Herein, a series of selenides with enhanced configuration entropy are designed and prepared to improve polarization loss capacity. Due to the different radii of the mixed ions and the Jahn‐Teller distortion effect, the local charge of the selenides is effectively modulated by the presence of defects and strong lattice distortions inside the lattice. Uneven distribution of charge at defects and formation of boundaries promotes defect‐induced polarization and interface polarization, respectively. Compared to single NiSe2, high‐entropy (NiFeCuCoMn)Se2 with an entropy value of 1.53R has more severe lattice defects and suitable impedance matching properties, exhibiting good EM absorption properties both in the absorption intensity and respond frequency. Tailoring the local charge density via an entropy strategy paves a new way for the high‐performance EM absorption materials. [ABSTRACT FROM AUTHOR]

Metal selenides (MSes) have great potential as candidate anode materials in high‐specific‐energy sodium‐ion batteries (SIBs) but are plagued by rapid capacity degradation and slow kinetics. Here, it is reveal that the Bi2Se3 anode discharge process involves multiple‐types of sodium polyselenides (Na‐pSex) which suffer from terrible dissolution and shuttling properties. Based on these observations, a nanoflower‐like composite of dual carbon‐confined Bi2Se3−x crystallites is designed via facile defect chemistry. The robust dual N‐doped carbon layer suppresses the precipitation and aggregation of Bi2Se3, significantly alleviating the dissolution and shuttle effect of Na‐pSex. Theoretical calculations indicate that the pyridine/pyrrole nitrogen sites exhibit strong van der Waals resistance and chemisorption properties against Na2Se4 and Na2Se2. Furthermore, the abundant Se vacancies improve the inherent conductivity of Bi2Se3, reduce the diffusion barrier of Na+, and accelerate the reaction kinetics. Consequently, the resulting Bi2Se3−x@DNC electrode exhibits extraordinary durability (over 2000 cycles at 10.0 A g−1) and high‐rate capability (354.4 mAh g−1 at 75.0 A g−1), propelling the battery performance to new heights. Encouragingly, the assembled hybrid capacitor displays competitive rate performance and an ultra‐long lifespan exceeding 40 000 cycles, making the Bi2Se3−x@DNC electrode a promising candidate for SIBs. [ABSTRACT FROM AUTHOR]

Metal selenides with excellent electronic conductivity and high theoretical capacity present great superiority as alternative anodes in sodium ion batteries (SIBs). However, they face huge challenges such as severe sodium polyselenides shuttling and slow sodium ion diffusion kinetics. To address these issues, entropy regulation strategy is employed to optimize the presence of Se vacancies and successfully prepared NiCoFeMnCr/CNTs (HE‐MSe/CNTs) rich in Se vacancies. This material enhances the adsorption energy for shuttle compounds like Na2Se2 and Na2Se4, effectively limiting the dissolution of polyselenides and improving the diffusion kinetics of sodium ions as well as the structural thermodynamics of the NaxHE‐MSe/CNTs adsorption phase. Experimental results indicate that HE‐MSe/CNTs achieve a highly reversible sodium storage process involving intercalation and conversion reaction mechanisms. This enables a superior rate capability of 400.4 mAh g −1 at a high current density of 5 A g−1, and long‐term durability with 90% retention after 1000 cycles at 1 A g−1. Therefore, utilizing entropy regulation to customize vacancy formation provides new insights and methods for enhancing the performance of SIB anodes. [ABSTRACT FROM AUTHOR]

The conversion of a functional group into another represents the core of organic synthesis. Within the arena of functional group interconversions, oxidative and reductive transformations occupy a privileged position and the development of new sustainable, selective, and general methodologies continue to attract significant interest. Owing to the versatility of their chemistry, selenium compounds offer significant opportunities to achieve both oxidation and reduction of a wide range of functional groups. Additionally, the possibility to generate in situ the active oxidant or reducing selenium species from suitable inert precursors enables the development of catalytic processes. In this review, recent advances in selenium‐mediated oxidative and reductive functional group interconversions, with particular emphasis on cutting‐edge researches bringing about new insights into the comprehension of their mechanistic aspects, will be discussed. [ABSTRACT FROM AUTHOR]

In this research, we first fabricated Fe3O4@Dop-Triazine-CuCl2 nanocatalyst by simple method, then its catalytic activity was investigated in the preparation of various derivatives of aryl-heteroaryl and di-heteroaryl selenides through C–Se coupling reactions of aryl iodides with powder selenium and various derivatives of heterocyclic compounds (with active C–H bonds). The catalyst exhibited spherical morphology with a diameter of approximately 20–30 nm and a magnetic saturation moment of 50.032 emu/g. The hydrocarbon content was measured to be around 12% by weight. In this method, a wide range of aryl-heteroaryl and di-heteroaryl selenides (36 examples) were synthesized with high yields (85–97%) using catalytic amount of the Fe3O4@Dop-Triazine-CuCl2 nanomaterial in the presence of KHCO3 in [BMIM]PF6 as solvent. This method has several remarkable features, which can be mentioned as follows: the synthesis of aryl-heteroaryl and di-heteroaryl selenide derivatives with high yields, performing the reactions in a suitable time (4 h), the applicability of this catalytic system for a wide range of substrates, the use of ionic liquid as solvent, high efficiency of Fe3O4@Dop-Triazine-CuCl2 catalyst, simple separation and high reusability of nanocatalyst. [ABSTRACT FROM AUTHOR]

A nickel‐catalyzed cross‐coupling reaction has been developed using two distinct electrophiles: an aryl alkyl selenide and an aryl bromide. The organoselenium compound, due to the lower bond dissociation energy of the C−Se bond, acts as a pseudohalide. This one‐pot reaction proceeds by cleaving the C−Se bond, producing the desired biaryls in moderate to good yields. The use of commercially available aryl bromides eliminates the handling of pre‐formed organomagnesium reagents, enhancing the practicality and applicability of this approach. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Unsymmetric sulfides and selenides have great applications in the pharmaceutical field. Herein, we describe the reductive coupling reaction of xanthate esters with sulfur‐containing and selenium‐containing compounds (thio(seleno)sulfonates and disulfides(selenides)) under the nickel‐catalyzed condition. It provides a mild and effective method for the synthesis of unsymmetric sulfides and selenides which has the advantages of mild reaction conditions, high yields and a wide range of substrates. [ABSTRACT FROM AUTHOR]

We report a novel bimetallic selenide Cu3TaSe4 anode for sodium-ion batteries synthesized via a one-step solid-state method. The integration of Ta–Se motifs into copper selenide forms a cubic grid structure that prevents copper atom aggregation and mitigates electrode failure. Cu3TaSe4 exhibits a high specific capacity of 305 mAh g−1 at 1 C, excellent rate performance of 286 mAh g−1 at 50 C, and superior cycling stability with 272 mAh g−1 after 3500 cycles at 20 C. This work demonstrates the potential of bimetallic selenides in enhancing sodium-ion battery performance. [ABSTRACT FROM AUTHOR]

The development of high-performance hydrogen peroxide (H2O2) sensors is critical for various applications, including environmental monitoring, industrial processes, and biomedical diagnostics. This study explores the development of efficient and selective H2O2 sensors based on bismuth oxide/bismuth oxyselenide (Bi2O3/Bi2O2Se) nanocomposites. The Bi2O3/Bi2O2Se nanocomposites were synthesized using a simple solution-processing method at room temperature, resulting in a unique heterostructure with remarkable electrochemical characteristics for H2O2 detection. Characterization techniques, including powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), confirmed the successful formation of the nanocomposites and their structural integrity. The synthesis time was varied to obtain the composites with different Se contents. The end goal was to obtain phase pure Bi2O2Se. Electrochemical measurements revealed that the Bi2O3/Bi2O2Se composite formed under optimal synthesis conditions displayed high sensitivity (75.7 µA µM−1 cm−2) and excellent selectivity towards H2O2 detection, along with a wide linear detection range (0–15 µM). The superior performance is attributed to the synergistic effect between Bi2O3 and Bi2O2Se, enhancing electron transfer and creating more active sites for H2O2 oxidation. These findings suggest that Bi2O3/Bi2O2Se nanocomposites hold great potential as advanced H2O2 sensors for practical applications. [ABSTRACT FROM AUTHOR]

Selenium-containing molecules represent a valuable class of compounds with a variety of applications in chemical and biological fields. Selenated reagents are used as intermediates to introduce functional groups (e.g., double bonds) onto different substrates or in the synthesis of various selenated derivatives. Among the variety of selenium-containing reagents, silyl selenides are frequently used to transfer a selenated moiety due to the smooth functionalization of the Se-Si bond, which allows for the generation of selenium nucleophilic species under mild conditions. While the use of the analogous sulfur nucleophiles, namely silyl sulfides, has been widely explored, a relatively limited number of reports on selenosilanes have been provided. This contribution will focus on the application of selenosilanes as nucleophiles in a variety of organic transformations, as well as under radical and redox conditions. The use of silyl selenides to prepare metal complexes and as selenium precursors of materials for atomic layer deposition will also be discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal selenides are promising anode candidates for sodium ion batteries (SIBs) because of their high theoretical capacity, low cost, and environmental friendship. However, the low rate capability at high current density due to its inherent low electrical conductivity and poor cycle stability caused by inevitable volume variations during cycling frustrate its practical applications. Herein, we have developed a simple metallic-organic frameworks (MOFs)-derived selenide strategy to synthesize a series of heterogeneous bimetallic selenides encapsulated within graphene aerogels (GA) as anodes for SIBs. The bimetallic selenides/GA composites have unique structural characteristics that can shorten the migration path for Na+/electrons and accommodate the volume variations via additional void space during cycling. The built-in electric fields induced at the heterointerfaces can greatly reduce the activation energy for rapid charge transfer kinetics and promote the diffusion of Na+/electrons. GA is also beneficial for accommodating the volume variations during cycling and improving conductivity. As an advanced anode for SIBs, the MoSe2-Cu1.82Se@GA with a special porous octahedron can deliver the highest capacity of 444.8 mAh/g at a high rate of 1 A/g even after 1000 cycles among the bimetallic selenides/GA composites. [ABSTRACT FROM AUTHOR]

Rocking‐chair configurations based on advanced anodes with reliable zinc‐ion storage can intrinsically avoid the deterioration of flexible zinc‐ion energy devices by corrosion, dendrites, and inadequate mechanical stability of zinc metal, yet the identification of durable anode materials is still challenging. Herein, the first reported conversion‐type Cu2‐xSe is proposed as an ultra‐stable anode for flexible rocking‐chair aqueous zinc‐ion batteries. Differing from these well‐recognized intercalation‐type copper selenide anodes, the unique Cu2‐xSe structure features a preferred thermodynamic deep transformation path, and the high‐reversible conversion reaction is fully illuminated by in situ synchrotron X‐ray diffraction and substantial ex situ characterization, demonstrating an outstanding performance combination of high capacity (150 mAh g−1 at 0.5 A g−1) and record‐high stability (91% capacity retention after 20 000 cycles at 5 A g−1 in Cu2‐xSe||ZnxMnO2 full cells). Consequently, fiber‐shaped batteries using Cu2‐xSe as the anode are successfully assembled and exhibited an ultra‐long life (89.8% capacity retention after 900 cycles) and extraordinary flexibility (98% capacity retention after 4500 cycles of bending), far exceeding those of representative flexible batteries previously reported. The findings provide novel insights into the energy storage mechanism of copper selenides and, as an elegant forerunner, offer a plausible path for the development of rocking‐chair flexible aqueous zinc‐ion batteries. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is considered to be a green and flexible strategy for the mass production of hydrogen fuel, while the high cost and insufficent activity of current cathode catalysts severely suffocate the widespread thriving of hydrogen economy. Herein, we present a bottom‐up assembly strategy to the controllable construction of 2D/2D heterojunctions built from cobalt‐iron selenide nanolamellas and Ti3C2Tx MXene nanosheets. This unique architectural design gives the resulting CoyFe1‐ySe2/Ti3C2Tx catalysts a series of interesting structural advantages, such as 2D/2D heterostructure, large active surface areas, modulated electronic structure, uniform CoyFe1‐ySe2 dispersion, and good electron conductivity, thereby leading to strong synergistic coupling effects. As a consequence, the optimized Co0.7Fe0.3Se2/Ti3C2Tx electrocatalyst with an appropriate Co/Fe ratio possesses unusual hydrogen evolution properties in terms of a low overpotential of 69 mV at 10 mA cm−2, a small Tafel slope of 51 mV dec−1 and reliable long‐term durability, which are more competitive than those of bare Ti3C2Tx, FeSe2 and CoSe catalysts. [ABSTRACT FROM AUTHOR]

To achieve high‐energy‐density and safe lithium‐metal batteries (LMBs), solid‐state electrolytes (SSEs) that exhibit fast Li‐ion conductivity and good stability against lithium metal are of great importance. This study presents a systematic exploration of selenide‐based materials as potential SSE candidates. Initially, Li8SeN2 and Li7PSe6 were selected from 25 ternary selenides based on their ability to form stable interfaces with lithium metal. Subsequently, their favorable electronic insulation and mechanical properties were verified. Furthermore, extensive theoretical investigations were conducted to elucidate the fundamental mechanisms underlying Li‐ion migration in Li8SeN2, Li7PSe6, and derived Li6PSe5X (X = Cl, Br, I). Notably, the highly favorable Li‐ion conduction mechanism of vacancy diffusion was identified in Li6PSe5Cl and Li7PSe6, which exhibited remarkably low activation energies of 0.21 and 0.23 eV, and conductivity values of 3.85 × 10−2 and 2.47 × 10−2 S cm−1 at 300 K, respectively. In contrast, Li‐ion migration in Li8SeN2 was found to occur via a substitution mechanism with a significant diffusion energy barrier, resulting in a high activation energy and low Li‐ion conductivity of 0.54 eV and 3.6 × 10−6 S cm−1, respectively. Throughout this study, it was found that the ab initio molecular dynamics and nudged elastic band methods are complementary in revealing the Li‐ion conduction mechanisms. Utilizing both methods proved to be efficient, as relying on only one of them would be insufficient. The discoveries made and methodology presented in this work lay a solid foundation and provide valuable insights for future research on SSEs for LMBs. [ABSTRACT FROM AUTHOR]

Hydrogen selenide (H2Se) is an emerging biomolecule of interest with similar properties to that of other gaseous signaling molecules (i.e., gasotransmitters that include nitric oxide, carbon monoxide, and hydrogen sulfide). H2Se is enzymatically generated in humans where it serves as a key metabolic intermediate in the production of selenoproteins and other selenium-containing biomolecules. However, beyond its participation in biosynthetic pathways, its involvement in cellular signaling or other biological mechanisms remains unclear. To uncover its true biological significance, H2Se-specific chemical tools capable of functioning under physiological conditions are required but lacking in comparison to those that exist for other gasotransmitters. Recently, researchers have begun to fill this unmet need by developing new H2Se-releasing compounds, along with pioneering methods for selenide detection and quantification. In combination, the chemical tools highlighted in this review have the potential to spark groundbreaking explorations into the chemical biology of H2Se, which may lead to its branding as the fourth official gasotransmitter. [ABSTRACT FROM AUTHOR]

In this study, carbon nanotubes (CNTs) coated with various phases of nanostructured nickel selenides were successfully synthesized with a simple and effective technique. These nanocomposites were then used as highly effective electrocatalysts for the urea oxidation reaction (UOR). The strategy involved depositing CNTs onto stainless steel (SS) foam using chemical vapor deposition, followed by pulse-reversal electrodeposition of nickel selenides in a layer-by-layer fabrication process. Different phases of nanostructured nickel selenides, such as NiSe 2 , NiSe 2 /Ni 0.85 Se, and Ni 0.85 Se, were successfully deposited on the surface of CNTs by controlling the reversal potential. Among all the different nanocomposites, the Ni 0.85 Se@CNTs-SS electrode exhibited the best electrocatalytic activity towards UOR. It required only a low overpotential, about 158 mV, to reach a benchmarking current density of 10 mA cm−2, and showed a low Tafel slope value of 85 mV dec−1. Additionally, the results of the prolonged stability study for 24 h confirmed the remarkable electrochemical stability of the Ni 0.85 Se@CNTs-SS electrode. After conducting stability studies, the overpotential shifted from 158 mV to 107 mV. This shift is due to the activation of the electrocatalyst during the stability test. The excellent electrocatalytic activity observed after the stability test is attributed to the presence of hydroxide and oxyhydroxide phases, which are remarkably active phases. This is the first-ever report where the Ni 0.85 Se@CNTs-SS nanocomposite electrode is shown to hold great potential as an effective electrocatalyst for UOR, which is an important step toward the design of a future electrocatalyst for UOR. • Various phases of nickel selenides were deposited on free-standing CNTs. • The deposition was achieved by using a facile PR electrodeposition. • Ni 0.85 Se@CNTs-SS electrode showed superior electrocatalytic activity towards UOR. • Ni 0.85 Se@CNTs-SS electrode demonstrated excellent electrochemical stability. [ABSTRACT FROM AUTHOR]

Iron selenide (FeSe2), cobalt selenide (Co3Se4), and iron cobalt selenide (FeCo2Se4) have been synthesized via a two-step hydrothermal process. The formation of FeSe2, Co3Se4, and FeCo2Se4 has been proven by sample characterization to support their catalytic activity as the counter electrodes for dye-sensitized solar cells (DSSCs). The poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)/propylene carbonate (PC)/1,2-dimethoxyethane (DME)/1-methyl-3-propyl imidazolium iodide (MPII)/sodium iodide (NaI)/iodine (I2) gel electrolytes were assembled into DSSCs with FeCo2Se4, FeSe2, Co3Se4, or platinum (Pt) as the counter electrode. The DSSC with FeCo2Se4 counter electrode shows an efficiency of 8.55%, whereas Pt counter electrode shows an efficiency of 7.06%. The highest performance of DSSC achieved with FeCo2Se4 can be attributed to its highest surface area and pore volume. Hence, FeCo2Se4 can be used as a Pt-free counter electrode for high-performance DSSCs. [ABSTRACT FROM AUTHOR]

The chemical reduction within a family of organic selenocyanates, as masked selenols, using reducing agents, such as Rongalite, sodium dithionite, and sodium thiosulfate is investigated. Using Rongalite, the corresponding diselenides were obtained quantitatively and selectively in very good to excellent yields (51–100 %) starting from alkyl, aryl, and benzyl selenocyanates. The scope of the reaction is unaffected by the electronic nature of the substituents. Furthermore, the reducing agent, Rongalite, is compatible with hydrolysable and reducing‐sensitive functional groups. Additionally, a simple methodology employing the in‐situ generated benzyl selenolate anion (PhCH2Se−) to promote aliphatic nucleophilic substitution, epoxide ring opening, and Michael addition reactions has been developed; thus, extending the structural diversity of the synthesized selenium derivatives. [ABSTRACT FROM AUTHOR]

Gallylene supported by a bis(oxazolinyl)(phenyl)methanide (Boxm) ligand was synthesized and structurally characterized. The reaction of this gallylene with triphenylphosphine sulfide/selenide yielded dimeric gallium sulfide and selenide. These compounds could be converted to monomeric terminal sulfide and selenide by coordination of an external Lewis base such as an N‐heterocyclic carbene (NHC or IMe4) and 4‐dimethylaminopyridiene (DMAP). These doubly‐base‐stabilized gallium sulfide/selenide reacted with phenyl isocyanate to give the corresponding cycloadducts by releasing the Lewis base, indicating the formation of a single‐base‐stabilized gallium sulfide/selenide intermediate. [ABSTRACT FROM AUTHOR]

This work demonstrates that the packaging material commonly called "bubble wraps" (Aeroplast) can be leveraged to serve as a probe to visible sunlight exposure. This probe relies on a newly developed layered metal selenide photocatalyst with the general formula (DMAH)2xMnxSn3–xSe6 (DMSe‐1) (x = 1.3–1.7; DMAH+ = dimethylammonium), featuring a narrow bandgap of 0.76 eV, in addition to an indicator dye and a reducing agent. The photochemically sensitive probe is introduced into the air‐filled compartments of bubble wraps and undergoes photocatalytic degradation, resulting in a chromatic response to sunlight exposure. The probe's sensitivity to variable irradiation doses can be adjusted by varying the amount of the photocatalyst. The color intensity correlates with the absorbed irradiation dose, allowing for qualitative assessment by the naked eye or quantitative measurement using the RGB color system. The results obtained from the new probe agree with those obtained from standard sunlight pyranometers (r = 0.98), with an average error of <15%. This suggests that beyond their use as protective coatings, bubble wraps can be successfully repurposed as visible light sensors. Furthermore, this study describes the initial use of metal chalcogenides as visible light probes, potentially paving the way for the development of innovative light‐sensitive materials. [ABSTRACT FROM AUTHOR]

Metal selenides have garnered significant attention as promising anode materials for sodium-ion batteries, thanks to their high theoretical capacity, excellent conductivity, and natural abundance. However, their potential is hampered by disappointing capacity retention and unsatisfactory lifespan, primarily attributed to volume expansion and unwanted structural collapse resulting from the insertion and extraction of relatively large Na+ ions during the charge and discharge processes. This feature article provides a brief overview of our endeavors to address the challenges associated with metal selenide-based anode materials, aiming to achieve high-performance electrode materials for sodium-ion batteries. Our strategy encompasses nanostructure design, materials composite engineering, heteroatoms doping, and topography and interface engineering. Additionally, future research directions are also outlined. [ABSTRACT FROM AUTHOR]

The general synthesis of heteroleptic acyclic silylenes with a bulky carbazolyl substituent (dtbpCbz) is detailed and a series of compounds with a chalcogenide substituent of the type [(dtbpCbz)SiE16R] (E16R=OtBu, SEt, SePh, TePh) is reported. With the bulky carbazolyl substituent present, the chalcogenide moiety can be very small, as is shown by incorporating groups as small as ethyl, phenyl or tert‐butyl. For the first time, the electronic properties of the silylene can be tuned along a complete series of chalcogenide substituents. The effects are clearly visible in the NMR and UV/Vis spectra, and were rationalised by DFT computations. The reactivity of the heaviest chalcogenide‐substituted silylenes was probed by reactions with trimethylphosphine selenide and the terphenyl azide TerN3 (Ter=2,6‐dimesitylphenyl). [ABSTRACT FROM AUTHOR]

Copper selenide nanoparticles (Cu2-x Se NPs) have received a lot of attention in recent decades due to their interesting properties and potential applications in various areas such as electronics, health, solar cells, etc. In this study, details of the synthesis and characterization of copper selenide nanoparticles modified with gum arabic (GA) are reported. Also, through transmission electronic microscopy (TEM) analysis, the transformation of the morphology and particle size of copper selenide nanoparticles in aqueous solution was studied. In addition, we present an antimicrobial study with different microorganisms such as Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Candida albiacans (C. albicans). Copper selenide nanoparticles were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry analysis (DSC) and TEM. XRD confirmed the crystal-line structure of the nanoparticles such as cubic berzelanite with a particle size of 6 nm ± 0.5. FTIR and TGA corroborated the surface modification of copper selenide nanoparticles with gum arabic, and DSC suggested a change in the structural phase from cubic to hexagonal. TEM analysis demonstrated that the surface modification of the Cu2-x Se NPs stabilized the nanostructure of the particles, preventing changes in the morphology and particle size. The antimicrobial susceptibility analysis of copper selenide nanoparticles indicated that they have the ability to inhibit the microbial growth of Staphylococcus aureus, Escherichia coli and Candida albicans. [ABSTRACT FROM AUTHOR]

The redistribution of electrons is driven by the electric field at the heterogeneous interface, optimizing the electronic structure of the anode material and improving the reaction kinetics. This optimization contributes to the enhanced sodium storage performance of transition metal selenides with the dual-carbon-confined strategy. [Display omitted] Transition metal selenides (TMSs) stand out as a promising anode material for sodium-ion batteries (SIBs) owing to their natural resources and exceptional sodium storage capacity. Despite these advantages, their practical application faces challenges, such as poor electronic conductivity, sluggish reaction kinetics and severe agglomeration during electrochemical reactions, hindering their effective utilization. Herein, the dual-carbon-confined CoSe 2 /FeSe 2 @NC@C nanocubes with heterogeneous structure are synthesized using ZIF-67 as the template by ion exchange, resorcin-formaldehyde (RF) coating, and subsequent in situ carbonization and selenidation. The N -doped porous carbon promotes rapid electrolyte penetration and minimizes the agglomeration of active materials during charging and discharging, while the RF-derived carbon framework reduces the cycling stress and keeps the integrity of the material structure. More importantly, the built-in electric field at the heterogeneous boundary layer drives electron redistribution, optimizing the electronic structure and enhancing the reaction kinetics of the anode material. Based on this, the nanocubes of CoSe 2 /FeSe 2 @NC@C exhibits superb sodium storage performance, delivering a high discharge capacity of 512.6 mA h g−1 at 0.5 A g−1 after 150 cycles and giving a discharge capacity of 298.2 mA h g−1 at 10 A g−1 with a CE close to 100.0 % even after 1000 cycles. This study proposes a viable method to synthesize advanced anodes for SIBs by a synergy effect of heterogeneous interfacial engineering and a carbon confinement strategy. [ABSTRACT FROM AUTHOR]

An efficiently aerobic dehydrazination of arylhydrazines promoted by potassium tert‐butoxide (tBuOK) is detailed in this study. This method smoothly produces aromatics analogues from arylhydrazines using catalytic amount of tBuOK under practical conditions, exhibiting excellent functional group tolerance and a broad substrate scope. The application potential of this approach is further demonstrated through the preparation of deuterated, iodinated and brominated aromatics. Moreover, it shows that this aerobic base‐mediated dehydrazination could be utilized to prepare unsymmetrical aryl sulfides, selenides and tellurides with high efficiency. [ABSTRACT FROM AUTHOR]

We present a comprehensive investigation into the potential of n-type indium-doped cadmium selenide telluride (CST:In) as a high-performance candidate for solar cell applications, without the need for resource-intensive post-growth treatments that are required for CdTe:In. We compared undoped CST and CST:In crystals under different growth conditions, analyzing their structural and electronic properties using x-ray diffraction (XRD), electron probe microanalysis (EPMA), current–voltage (IV) and Hall effect measurements, time-resolved photoluminescence (TRPL), optical transmission, and photoluminescence (PL) mapping. The results reveal that as-grown CST:In crystals achieve nearly 100% carrier activation, yielding an electron concentration of 9.5 × 1018 cm−3, mobility of 653 cm2/V·s and a 5 ns lifetime which approaches the radiative limit. Furthermore, comparison of PL maps from crystal growths having different cooling profiles suggests a strong effect of cooling rate on selenium segregation and cubic/hexagonal/polytype phase distribution. Slower cooling leads to a more homogeneous cubic structure with lower Se segregation, while a faster cooling rate results in increased Se segregation, and twin boundaries and stacking faults with polytypic and hexagonal character. [ABSTRACT FROM AUTHOR]

Metal selenides are widely considered as an emerging anode electrode material for lithium‐ion batteries (LIBs). Hence, the present study uses a conductive carbon materials matrix such as carbon nanotubes (CNTs) with copper–iron selenide (CuFeSe2). The composites (CuFeSe2@CNTs) are synthesized by a hydrothermal method and examined for electrochemical performance as anode applications in LIBs. Herein, the CuFeSe2@CNTs show excellent specific capacity of 783.7 and 720.6 mA h g−1 at 0.1 and 1 A g−1, respectively. This composite further exhibits a high‐capacity value compared to only FeSe2 and CuFeSe2 and a reversible capacity of 691 mA h g−1 after 200 cycles at 1 A g−1 current density. Moreover, the homogeneous combination of CuFeSe2 nanoflakes and CNTs provides structural stability that reduces the volume change during lithium‐ion interactions and successively improves the conductivity of the complex, which is advantageous for better ion and electron kinetics during the reaction. [ABSTRACT FROM AUTHOR]

The development of new sulfide and selenide-based thermoelectric (TE) materials is critical for the mass production of TE devices due to the higher earth abundance of S/Se than Te. In this work, we have prepared single crystals of Ag-substituted BaCu2−xAgxSe2 (x = 0 – 0.8) by direct fusion of elements at high temperatures. As characterized by single crystal X-ray diffraction (SCXRD) studies, each of the structures (space group: Pnma) contains two transition metal sites (M1 and M2), and the Ag atoms are disordered with Cu atoms at both sites with a slight preference for the M2 site. Phase pure polycrystalline BaCu2−xAgxSe2 (x = 0 – 1.0) samples have also been synthesized, which are semiconductors as confirmed by optical absorption and resistivity studies. All these samples show positive values of the Seebeck coefficient, suggesting the p-type electrical conduction. Our thermal conductivity (ktot) studies demonstrate a remarkable drop in ktot values on increasing the Ag-substitution in the BaCu2−xAgxSe2 phases with the lowest ktot value of 0.33 W m−1 K−1 (673 K) for the x = 1.0 sample. Our studies show the potential of the BaCuAgSe2 for TE applications with higher zT values if the hole concentration of the phase can be fully optimized. [ABSTRACT FROM AUTHOR]

A series of phenyl β-carbonyl selenides with o-ester functionality substituted on the oxygen atom with chiral and achiral alkyl groups was synthesized. All compounds are the first examples of this type of organoselenium derivatives with an ester substituent in the ortho position. The obtained derivatives were tested as antioxidants and anticancer agents to see the influence of an ester functionality on the bioactivity of β-carbonyl selenides by replacing the o-amide group with an o-ester group. The best results as an antioxidant agent were observed for O-((1R,2S,5R)-(−)-2-isopropyl-5-methylcyclohexyl)-2-((2-oxopropyl)selanyl)benzoate. The most cytotoxic derivative against breast cancer MCF-7 cell lines was O-(methyl)-2-((2-oxopropyl)selanyl)benzoate and against human promyelocytic leukemia HL-60 was O-(2-pentyl)-2-((2-oxopropyl)selanyl)benzoate. [ABSTRACT FROM AUTHOR]

In this study, magnesium Selenide (MgSe) thin films were synthesized on glass substrate using the chemical bath deposition (CBD) method for thermoelectric power generation. After cleaning of glass substrate, selenium powder was dissolved in nitric acid to produce SeO 2 and magnesium chloride was then introduced as the source of magnesium. Both SeO 2 and MgCl 2 were dissolved in 100 ml of dI water and later, these solutions were unified gradually. After that, the cleaned glass substrates were placed in the solution, while keeping the reaction temperature constant at 50o C for the deposition durations of 24, 48, 72, and 96 h. A number of characterization techniques, namely X-ray Diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopy (SEM) were performed for structural and surface analysis of grown thin films. The effect of deposition time duration on the thermoelectric properties was investigated in depth using the Seebeck and Hall systems. It was found that the values of the Seebeck coefficient and power factor obey the increasing trend with maximum values 196.93 μV/K and 21.5 × 10−8 W/mK2 respectively. These observed values are seems to be the highest values for magnesium selenide thin film ever reported in the literature according to the best of our knowledge. Therefore, we have concluded that MgSe thin films supposed to be emerging material for thermoelectric power generation applications. [ABSTRACT FROM AUTHOR]

Herein, a series of novel ferrocenyl/phenyl/thiophenyl‐azoles was disclosed by vinylic amination of ferrocenyl/phenyl/thiophenyl substituted β‐chloro cinnamaldehydes and acrylonitriles. A highly economical and robust chalcogen‐stabilized iron selenide carbonyl cluster Fe3Se2(CO)9 worked as an efficient catalyst under aerobic conditions. The amination of ferrocenyl/phenyl/thiophenyl substituted β‐chloro‐vinylic Csp2‐Cl with azole derivatives was fully established and fabrication of the Csp2‐N bond was completely supported by various spectral analysis. Moreover, wide range of substrates with functionally different azoles were investigated for the present reaction and good to excellent transformation was recorded. Some of the selected ferrocenated azole derivatives were screened for anti‐cancer activity against the prostate cancer cells (PC‐3) and found to be highly active at low concentration of 5.77 μM with IC50 value. Furthermore, HOMO and LUMO levels and energy gap of some selected compounds were calculated by the density functional theory (DFT). [ABSTRACT FROM AUTHOR]

Binary transition metal selenides (BTMSs) are more promising than single transition metal selenides (TMS) as anode materials of sodium-ion batteries (SIBs). However, it is still very challenging to prepare high-performance BTMSs in the pure phase, instead of a mixture of two TMSs. In this study, a binary metal center-based MOF derived selenization strategy was developed to prepare iron–cobalt selenide (Fe2CoSe4@NC) and iron–nickel selenide (Fe2NiSe4@NC) nanocomposites in the single phase and when wrapped with carbon layers. As the anode material of SIBs, Fe2CoSe4@NC exhibits higher long-term cycling performance than Fe2NiSe4@NC, maintaining a capacity of 352 mAh g−1 after 2100 cycles at 1.0 A g−1, which is ascribed to the higher percentage of the nanopores, larger lattice spacing, and faster Na+ diffusion rate in the electrode materials of the former rather than the latter. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) is essential to the water splitting and CO2 reduction reactions, while this reaction is kinetically sluggish and demands the efficient electrocatalyst. Transition metal selenides (TMSes) have gained greater attention as nonprecious metal‐based electrocatalysts due to their low cost, earth abundance, and high efficiency. Typically, TMSe can exhibit superior OER activity to their counterparts such as hydroxides/oxyhydroxides and sulfides. As such, their unique way to boost the catalytic activity is intriguing to researchers and many studies have been recently carried out. The last decades have witnessed the rapid development of TMSe‐based electrocatalysts in design and preparation for OER. However, there is still no exclusive review summarizing the recent development of this material for OER electrocatalysis. Herein, this article underscores the significant promise of TMSes in advancing the field of high‐performance OER electrocatalysts. The research progress is summarized and the importance of strategies to improve the performance of selenide electrodes including multimetal composite, hybrid composite with carbonaceous materials, morphological engineering, heterostructure engineering, and vacancies engineering is emphasized. Finally, the future challenges and opportunities concerning the improvement of TMSe electrocatalysts are outlined, which are essential for their further application in electrochemical energy conversion. [ABSTRACT FROM AUTHOR]

Quantum dots of I–III–VI ternary compounds exhibit unusual photophysical properties and technological utility, which attract attention and have been intensely investigated. CuInSe2 quantum dots are an environmentally friendly composition, a direct transition, and an adjustable bandgap. Here, we discuss the influence of the Cu/In molar ratio of CuInSe2 quantum dots on Cu-related defects and photo-physical properties, and CuInSe2 quantum dots are synthesized by a green, safe, and low-temperature method in triethylene glycol. The proportion of the +1 and +2 oxidation states of Cu in the quantum dots will change with the Cu/In molar atomic ratio. The +1-oxidation state of Cu will prolong the carrier recombination lifetime and provide favorable conditions for the transfer and collection of carriers. By adjusting for different defect types, we can better apply CISe quantum dots in devices and other fields. [ABSTRACT FROM AUTHOR]

Group IIIA metal chalcogenides are an auspicious material system due to their variability of properties and hence the multitude of application options, for example, in the fields of optoelectronic, thermoelectric, piezo‐, and ferroelectric devices. Indium and gallium selenide films are innovatively grown in a sequential PVD (physical vapor deposition) process starting from metal precursor layers of various thicknesses, which are then subject to chalcogenization in different selenium contents. The resulting thin films are investigated for structural and optical properties by Raman, XRD (X‐ray diffraction), and UV–Vis–NIR spectrometry, revealing that all the compounds In2Se3, InSe, In4Se3, Ga2Se3, and GaSe as well as different polytypes can be achieved depending on the metal/chalcogen ratio. Results from Raman and XRD spectroscopy are highly consistent, and also from the optical measurements changes in absorption characteristics can be correlated. The results indicate, that by fine‐tuning the selenium content, deliberately growing ultra‐thin layers of the different indium and gallium phases will be possible, thus opening up a promising route for 2D material fabrication. Given the scalability of the fabrication method, it is highly promising for large‐scale deployment of the materials. [ABSTRACT FROM AUTHOR]

We describe here the synthesis of isoselenochromenes via a nucleophilic selenocyclization reaction of benzodiynes with sodium selenide. The central parameters that affect this cyclization reaction were studied, and the best reaction conditions were applied to different substrates to determine the scope of the method. The results indicated that isoselenochromenes were obtained in higher yields when the reactions were performed by the addition of NaBH4 (3 equiv), at room temperature, under nitrogen atmosphere, to a solution of elemental selenium (2 equiv) in dimethylformamide (2 mL). After 1 h, a benzodiynes (0.25 mmol) solution in EtOH (3 mL) was added at room temperature. The reaction was stirred at 75 °C until the starting material was consumed. The best conditions were applied to benzodiynes having electron‐rich, electron poor aromatic rings, and alkyl groups directly bonded to the alkynes. The same reaction condition was extended to isothiochromene derivatives but failed to prepare isotelurochromenes. The isoselenochromenes were easily transformed into three new classes of organoselenium compounds using classical methods available in the literature. We also conducted several control experiments to propose a reaction mechanism. [ABSTRACT FROM AUTHOR]

Stimulus-responsive materials containing selenide under oxidizing conditions have wide application prospects, especially in biomedicine. Due to the intricate preparation process, the scarcity of studies on the structure–activity relationship of regulatory factors in the oxidative stimulus response poses challenges to material design. Herein, based on selenol-ene chemistry, a diverse library of unsymmetric selenides is synthesized, enabling systematic investigation into the regulation of selenide oxidative elimination with variable substituent groups and positions. The α/β-positions of β-carbonyl unsymmetric selenides are efficiently modified with electron-donating or electron-withdrawing groups through a one-pot, two-step reaction involving ammonolysis of γ-selenobutyrolactone (SBL), followed by nucleophilic addition with unsaturated acrylate. In situ NMR tracking shows that the oxidative elimination of selenide had a distinct substituent effect. Both the electron and steric effects of the substituent influence the induction period of the selenide oxidative and elimination reactions. With the optimal substituent and position, the selenides would exhibit a timebomb-type response upon oxidation stimulus. Finally, a novel amphiphilic polymer comprising selenide-linked polyethylene glycol (PEG) and cholesterol moieties is synthesized as a representative ROS-sensitive material and exhibits a time-dependent reduction in micelle size. [ABSTRACT FROM AUTHOR]

The La'erma and Qiongmo Au–Se deposits are characterized by a paragenetic Au–Se association hosted in the siliceous formation of the Cambrian Taiyangding Group in the western Qinling Orogen, central China. The La'erma and Qiongmo Au–Se deposits, which are considered to be the Carlin gold deposits, comprise a variety of selenides, native gold, and stibnite coexisting with baryte. Four stages have been recognized: sage I comprises pyrite and quartz with minor stibnite; stage II is composed mainly of sulfides; stage III is composed mainly of selenides; and stage IV is dominated by quartz–baryte–dickite. Stages II and III are the main metallogenic stages. Based on changes in mineral assemblages, combined with fluid inclusions and thermodynamic data, we evaluated the physicochemical conditions of the main metallogenic stages. The logfS2 values of ore-forming fluids at stage II ranged between −10.44 and −14.60 with logfSe2 being less than −10.70. Comparably, during stage III, which is characterized by numerous selenides, the logfS2 and logfSe2 ranged from −7.13 to −12.20 and −13.98 to −8.82, respectively. The occurrence of baryte during the mineralization suggests a consistently oxidizing condition, which can effectively remove Au from fluids. More importantly, this study emphasizes that the oxidizing condition was only a fundamental prerequisite for the deposition of selenides, and a high ∑Se/S ratio of the fluid ultimately controlled the precipitation of selenides. In the La'erma and Qiongmo deposits, intense water–rock reactions occurred as ore-forming fluids flowed into the Se-rich siliceous formations, resulting in an increase in the ∑Se/S ratio of the fluid and in the precipitation of selenides. [ABSTRACT FROM AUTHOR]

The pulsed cathodoluminescence spectra of zinc selenide at room temperature were recorded: feedstock and materials required for the synthesis of optical ceramics. Samples of the cubic phase ZnSe with stoichiometric composition were also studied in the presence of additional phases (hexagonal ZnSe and ZnO). Three characteristic luminescence bands were detected for single-phase cubic zinc selenide. For the cubic ZnSe with stoichiometric composition one strong line of interband luminescence with a width of 12–14 nm is observed in the region of 470 nm; with an excess of selenium, an additional broad band appears at 647 nm, and with an increased impurity content and a small excess of zinc a single band is observed at 588 nm. In two-phase materials containing cubic and hexagonal ZnSe as the main or additional phase luminescence is not observed at room temperature. In the spectrum of cubic ZnSe with an additional hexagonal ZnO phase, a strong broad doublet band of hexagonal ZnO appears at 525–900 nm in addition to the interband luminescence line with a wavelength that decreases from 470 to 466 nm with increasing ZnO content. A rapid analysis of the quality of the ZnSe material can be carried out on the basis of the presence or absence of these pulsed cathodoluminescence bands. [ABSTRACT FROM AUTHOR]

Applying the cohesive energy model, this research theoretically studies how the size of nanoparticles affects their optical characteristics. The findings demonstrate that optical characteristics are size-dependent for nanoparticles, with an exponentially growing energy gap for nanoparticles on a scale of less than 4 nm. As the size of nanoparticles is reduced, the absorption wavelength also decreases. Compounds undergo a transition to a higher energy spectral area (blue shift) when their wavelength decreases; this change can make these compounds effective in certain optical nanodevices. [ABSTRACT FROM AUTHOR]

A new member of the A2B5C5X16 family of compounds – the first one containing Se – has been synthesized. Following a one-step mechanochemical synthesis route, starting from the binary selenides and Mg metal, Cu2Mg5Sn5Se16 has been obtained. Structural evaluation was carried out using X-ray diffraction with subsequent Rietveld refinement. Cu2Mg5Sn5Se16 adopts the spinel type with space group Fd 3 ‾ m and exhibits a statistical distribution of Cu, Mg, and Sn on Wyckoff position 16d whereas Wyckoff position 8a is only occupied by Mg. Despite the fact that structures containing MgSe4 tetrahedra are rare in the literature, it appeared to be the most plausible way of distributing the cations in this compound. [ABSTRACT FROM AUTHOR]

Nickel diselenide (NiSe2), which has a high theoretical capacity, has attracted considerable attention as a promising anode material for sodium-ion batteries (SIBs). Nevertheless, the intrinsically low conductivity, large volume variation, and significant aggregation of NiSe2 during sodiation/desodiation remain significant obstacles to its application. Herein, we report flower-like Fe-doped NiSe2/C hybrid spheres (denoted as Fe-NiSe2/C) fabricated by a glucose intercalation strategy for efficient sodium storage. These Fe-NiSe2 /C hybrid spheres are composed of thin porous carbon nanosheets decorated with Fe-NiSe2 nanoparticles. In situ introduced carbon nanosheets derived from intercalated glucose accompanied by moderate Fe doping in NiSe2 nanoparticles can provide accelerated ion/electron transfer kinetics through fast ion channels in the flower-like architecture and intimately contacted interfaces between NiSe2 and carbon nanosheets as well as maintain structural integrity by alleviating volume variation. Consequently, the optimal anode of the Fe-NiSe2 /C hybrid spheres delivered a high discharge capacity of 415 mAh g-1 at 0.5 A g-1, outstanding rate capability (243 mAh g-1 at 5 A g-1), and significantly enhanced cycling stability (388 mAh g-1 at 1 A g-1 over 200 cycles). This work offers an efficient and valuable strategy for realizing tailored heteroatom doping in transition metal selenides, accompanied by an in situ combination of conductive carbonaceous networks for advanced alkali metal ion batteries. [ABSTRACT FROM AUTHOR]