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Gel electrolytes have attracted increasing attention for solid-state supercapacitors. An ideal gel electrolyte usually requires a combination of advantages of high ion migration rate, reasonable mechanical strength and robust water retention ability at the solid state for ensuring excellent work durability. Here we report a zwitterionic gel electrolyte that successfully brings the synergic advantages of robust water retention ability and ion migration channels, manifesting in superior electrochemical performance. When applying the zwitterionic gel electrolyte, our graphene-based solid-state supercapacitor reaches a volume capacitance of 300.8 F cm −3 at 0.8 A cm −3 with a rate capacity of only 14.9% capacitance loss as the current density increases from 0.8 to 20 A cm −3 , representing the best value among the previously reported graphene-based solid-state supercapacitors, to the best of our knowledge. We anticipate that zwitterionic gel electrolyte may be developed as a gel electrolyte in solid-state supercapacitors. Gel electrolytes are promising for solid-state supercapacitors, due to their favourable properties such as high ion migration rate, mechanical strength, and water retention. Here, the authors report on a zwitterionic gel electrolyte giving robust performance in graphene-based solid-state supercapacitors.

Layered materials have attracted tremendous interest for accessing two-dimensional structures. Materials such as graphite or transition metal dichalcogenides, in which the layers are held together by van der Waals interactions, can be exfoliated through a variety of processes in a manner that retains the structure and composition of the monolayers, but this has proven difficult for solids with stronger interlayer interactions. Here, we demonstrate the exfoliation of AgCrS2, a member of the AMX2 family (where A is a monovalent metal, M is a trivalent metal and X is a chalcogen), through intercalation with tetraalkylammonium cations, chosen for their suitable redox potential. The as-exfoliated nanosheets consist of Ag layers sandwiched between two CrS2 layers, similar to their structure in the bulk. They show superionic behaviour at room temperature, with an ionic conductivity of 33.2 mS cm−1 at 298 K that originates from Ag+ ions rapidly hopping between neighbouring tetrahedral interstices; in the bulk, this behaviour is only observed above 673 K.Layered materials held together by weak interactions can be exfoliated into monolayers that retain the structure and composition of their bulk counterpart, but this has remained challenging to achieve for non-van der Waals materials. Now, AgCrS2 has been exfoliated into such [CrS2]Ag[CrS2] nanosheets through intercalation with tetraalkylammonium cations chosen for their suitable redox potential. The nanosheets show superionic behaviour at room temperature.

Multiferroic materials, which simultaneously exhibit ferroelectricity and magnetism, have attracted substantial attention due to their fascinating physical properties and potential technological applications. With the trends towards device miniaturization, there is an increasing demand for the persistence of multiferroicity in single-layer materials at elevated temperatures. Here, we report high-temperature multiferroicity in single-layer CuCrSe 2 , which hosts room-temperature ferroelectricity and 120 K ferromagnetism. Notably, the ferromagnetic coupling in single-layer CuCrSe 2 is enhanced by the ferroelectricity-induced orbital shift of Cr atoms, which is distinct from both types I and II multiferroicity. These findings are supported by a combination of second-harmonic generation, piezo-response force microscopy, scanning transmission electron microscopy, magnetic, and Hall measurements. Our research provides not only an exemplary platform for delving into intrinsic magnetoelectric interactions at the single-layer limit but also sheds light on potential development of electronic and spintronic devices utilizing two-dimensional multiferroics. The authors observe multiferroicity in a single-layer non van der Waals material, CuCrSe 2 . The coexistence of room-temperature ferroelectricity and ferromagnetism up to 120 K is corroborated by a set of comprehensive experimental techniques.

Electrocatalytic N₂ reduction reaction (NRR) into ammonia (NH₃), especially if driven by renewable energy, represents a potentially clean and sustainable strategy for replacing traditional Haber–Bosch process and dealing with climate change effect. However, electrocatalytic NRR process under ambient conditions often suffers from low Faradaic efficiency and high overpotential. Developing newly regulative methods for highly efficient NRR electrocatalysts is of great significance for NH₃ synthesis. Here, we propose an interfacial engineering strategy for designing a class of strongly coupled hybrid materials as highly active electrocatalysts for catalytic N₂ fixation. X-ray absorption near-edge spectroscopy (XANES) spectra confirm the successful construction of strong bridging bonds (Co–N/S–C) at the interface between CoSₓ nanoparticles and NS-G (nitrogen- and sulfurdoped reduced graphene). These bridging bonds can accelerate the reaction kinetics by acting as an electron transport channel, enabling electrocatalytic NRR at a low overpotential. As expected, CoS₂/NS-G hybrids show superior NRR activity with a high NH₃ Faradaic efficiency of 25.9%at −0.05 V versus reversible hydrogen electrode (RHE). Moreover, this strategy is general and can be extended to a series of other strongly coupled metal sulfide hybrids. This work provides an approach to design advanced materials for ammonia production.

Yuxi Taihe Douchi (THDC) is a traditional fermented condiment from the multi-ethnic region of Yunnan Province, known for its distinctive sensory properties. However, the lack of characteristic flavor research has restricted its product iteration upgrade and commercial promotion. This study comprehensively investigated the flavor characteristics, flavor dynamic changes during fermentation, and their associations with microbial diversity in THDC. Results indicated that esters, phenols, and aldehydes were the predominant aroma compounds contributing to its aroma. A total of 22 key volatile flavor compounds (VFCs) were identified, among which 1-octen-3-ol, methional, benzene acetaldehyde, and 4-vinylguaiacol exhibited the highest odor activity values (OAVs) of 316.56, 378.10, 427.23, and 749.73, respectively. High-throughput sequencing identified ten dominant microbial genera in THDC, including Staphylococcus , Bacillus , Weissella , and Aspergillus . Spearman correlation analysis revealed that core microorganisms such as Acinetobacter , Achromobacter and Aspergillus were positively correlated with various free amino acids and aroma compounds. These findings enhance the understanding of microbial community succession in Yuxi THDC and offer a theoretical basis for flavor strain selection, thereby providing a theoretical foundation for flavor enhancement and development of novel Douchi products with regional characteristics.

Two-dimensional materials have been an ideal material platform for constructing flexible ultrathin-film supercapacitors, offering great advantages of flexibility, ultra-thinness and even transparency. Exploring new two-dimensional pseudocapacitive materials with high electrochemical activity is needed to achieve flexible ultrathin-film supercapacitors with higher energy densities. Here we report an inorganic graphene analogue, α 1 -vanadyl phosphate ultrathin nanosheets with less than six atomic layers, as a promising material to construct a flexible ultrathin-film pseudocapacitor in all-solid-state. The material exhibits a high potential plateau of ~ 1.0 V in aqueous solutions, approaching the electrochemical potential window of water (1.23 V). The as-established flexible supercapacitor achieves a high redox potential (1.0 V) and a high areal capacitance of 8,360.5 μF cm −2 , leading to a high energy density of 1.7 mWh cm −2 and a power density of 5.2 mW cm −2 . Graphene-like materials with pseudocapacitive characteristics are desirable for flexible solid-state pseudocapacitors. Here Wu et al . report such a graphene analogue, vanadyl phosphate ultrathin nanosheets, which exhibits excellent pseudocapacitive properties, leading to a high energy density.

In artificial photocatalysis, sluggish kinetics of hole transfer and the resulting high-charge recombination rate have been the Achilles’ heel of photocatalytic conversion efficiency. Here we demonstrate water-soluble molecules as co-catalysts to accelerate hole transfer for improved photocatalytic H 2 evolution activity. Trifluoroacetic acid (TFA), by virtue of its reversible redox couple TFA·/TFA − , serves as a homogeneous co-catalyst that not only maximizes the contact areas between co-catalysts and reactants but also greatly promotes hole transfer. Thus K 4 Nb 6 O 17 nanosheet catalysts achieve drastically increased photocatalytic H 2 production rate in the presence of TFA, up to 32 times with respect to the blank experiment. The molecular co-catalyst represents a new, simple and highly effective approach to suppress recombination of photogenerated charges, and has provided fertile new ground for creating high-efficiency photosynthesis systems, avoiding use of noble-metal co-catalysts. Enhancing the kinetics of hole transfer at photocatalytic surfaces serves to promote the overall efficiency closer to practically implementable levels. Here, the authors employ trifluoroacetic acid to achieve this goal and significantly improve the photocatalytic H 2 evolution activity of K 4 Nb 6 O 17 .

Inorganic graphene analogues (IGAs) are a conceptually new class of materials with attractive applications in next-generation flexible and transparent nanodevices. However, their species are only limited to layered compounds, and the difficulty in extension to non-layered compounds hampers their widespread applicability. Here we report the fabrication of large-area freestanding single layers of non-layered ZnSe with four-atomic thickness, using a strategy involving a lamellar hybrid intermediate. Their surface distortion, revealed by means of synchrotron radiation X-ray absorption fine structure spectroscopy, is shown to give rise to a unique electronic structure and an excellent structural stability, thus determining an enhanced solar water splitting efficiency and photostability. The ZnSe single layers exhibit a photocurrent density of 2.14 mA cm −2 at 0.72 V versus Ag/AgCl under 300 W Xe lamp irradiation, 195 times higher than that of bulk counterpart. This work opens the door for extending atomically thick IGAs to non-layered compounds and holds promise for a wealth of innovative applications. Ultrathin inorganic materials hold promise for a variety of applications, including flexible electronics. This work presents a fabrication method that permits the synthesis of large and flexible freestanding layers of zinc selenide that display a high-photocurrent density.

A method based on the adsorption of ions on the surface of two-dimensional (2D) nanosheets has been developed for photocatalytic CO 2 reduction. Isolated Bi ions, confined on the surface of TiO 2 nanosheets using a simple ionic adsorption method facilitate the formation of a built-in electric field that effectively promotes charge carrier separation. This leads to an improved performance of the photocatalytic CO 2 reduction process with the preferred conversion to CH 4 . The proposed surface ion-adsorption method is expected to provide an effective approach for the design of highly efficient photocatalytic systems. These findings could be very valuable in photocatalytic CO 2 reduction applications.

Subsurface regions critically govern surface events, such as the interactions with reactants in heterogeneous catalysis, thereby significantly modulating catalytic performance. However, precise control of subsurface atomic arrangement remains challenging due to complex metal-adsorbate interactions and limited structural accessibility. Here we achieve precise control of subsurface atomic layer in platinum-based intermetallic compounds through targeted positioning of heterometallic atoms to subsurface via in-situ constructed atomic diffusion pathways. This site-specific placement and subsequent thermodynamic-induced atomic rearrangement are governed by surface energy minimization and adsorbate-induced segregation. Through atomic-precision subsurface engineering, we successfully synthesize a series of L1 0 (face-centered tetragonal, fct)-PtFe@PtM sub , where M sub represents heteroatoms (Ru, Rh, Pd, Ag) incorporated into subsurface layers. As demonstrated, the as-synthesized L1 0 -PtFe@PtPd sub simultaneously stabilizes ligand and strain effects, thereby breaking the trade-off in L1 0 -PtM with Pt skin, where Pt skin typically quenches ligand effects while introducing strain effects. Consequently, L1 0 -PtFe@PtPd sub /C catalyst demonstrates practical proton exchange membrane fuel cells performance, simultaneously delivering high activity and durability. This work provides a rational strategy for catalyst design that promotes the understanding of subsurface active sites in heterogeneous catalysis. Subsurface structure dictates the catalytic activity in heterogeneous catalysis. Here, the authors report an atomic diffusion pathway mediated subsurface engineering strategy, enabling precise control of subsurface atomic layers in Pt-based intermetallic compounds.