Refractory metal-based MXenes refer to MXenes with M as a refractory metal. Due to their high conductivity, large specific surface area, multiple active sites, high photothermal conversion efficiency, adjustable surface groups, and controllable nanolayer spacing, they hold broad application prospects in various fields such as photoelectrocatalysis, biomedicine, water treatment, electromagnetic shielding, and sensors. The unique physical properties of refractory metal-based MXenes are related to their electronic and crystal structures. The interstitial layer causes the carbides to exhibit different behavior compared to the original metal. At the same time, different preparation methods have a great influence on the interlayer spacing and surface termination of refractory metal-based MXenes, thus affecting their performance. This review systematically summarizes the latest progress in the preparation methods and frontier applications of refractory metal-based MXenes, offering new insights for further development. Additionally, various characterization techniques and first-principles calculations are summarized, which are crucial for optimizing refractory metal-based MXenes for applications such as catalysis, energy storage, and sensors. In summary, the current challenges and future development prospects of refractory metal-based Mxenes are addressed, aiming to provide indispensable information for the intelligent design of 2D materials in the future.

Viruses can infiltrate the central nervous system and contribute to depression, which may include alterations in dopamine (DA) metabolism triggered by immune responses though the specific mechanisms involved remain unclear. Here, an electrochemical system to realize the real-time dynamic monitoring of DA with high sensitivity is proposed and it is demonstrated that the viral simulator polyinosinic-polycytidylic acid (poly(I:C)) can inhibit the release of DA (from 5.595 to 0.137 µm) in neurons from the perspective of single cells, cell populations and even in vivo through the combination of multiscale electrodes, including single nanowires, carbon fibers (CFs) and 2D flexible electrodes. These findings are associated with the increase in reactive oxygen species (ROS) produced by microglia. At the molecular level, poly(I:C) significantly decreases the expression of α-synuclein and increases its phosphorylation level, whereas ROS inhibitors can reverse these pathological changes and salvage DA release to half the initial level (≈2.6 µM). These results suggest that viruses may indirectly inhibit DA system function through ROS produced in inflammatory responses and that antioxidant activity may be a potential therapeutic strategy.

The crucial role of active hydrogen (H*) in photocatalytic CO methanation has long been overlooked, although recently, accelerating proton-coupled electron transfer (PCET) processes to enhance CH productivity and selectivity has garnered significant attention. Herein, a single-atom Pt-anchored HPMoO (Pt-PMo) is applied as an efficient proton-electron shuttle to facilitate the photocatalytic performance of NiCo layered double hydroxide (NiCo-LDH). The resultant Pt-PMo@NiCo-LDH exhibited superior CH productivity (723 µmol g h) with CH selectivity of 82.3%, showcasing a 24.9 times productivity enhancement over NiCo-LDH (29 µmol g h). Systematic investigations revealed that abundant H* is generated by the dissociation of HO on Pt sites and stored within Pt-PMo. Subsequently, the multiple H* rapidly migrated from Pt-PMo to the catalytic sites on NiCo-LDH by the engineered strong Mo─O─Ni/Co bonds, thereby significantly expediting the PCET process. The in situ DRIFTS and theoretical calculations elucidated that the Pt-PMo decreased the energy barrier for *CO protonation to *CHO (0.38-0.18 eV) and optimized the rate-determining step of *CH to *CH (0.64 eV), thus promoting highly active and selective CH generation. This work provided novel insights into achieving efficient photocatalytic CO methanation by modulating the fast generation and transport of active H*.

Coal is a promising precursor of hard carbon (HC) anodes for sodium-ion batteries (SIBs), by virtue of resource abundance, low cost, and high product yield. However, the concomitant inorganic salt is usually recognized as impurities and plays an obscure and even contradictory effect on the regulation of pore structure in HCs. Herein, a two-step pyrolysis procedure to the representative salty coal is performed, in which the acid washing program is selectively inserted. It is illuminated that salt acts as a template or activating agent for the generation of open pores at low temperatures but inhibits the closure of pores during the following high-temperature carbonization. The optimized HC delivers a reversible capacity of 322.4 mAh g, a high plateau capacity of 192 mAh g, and an initial coulombic efficiency of 80%, outperforming to most coal-based HCs. Assembled with an NVPOF cathode, the full-cell exhibits a high energy density of 284.7 Wh kg. This work not only provides a systematic understanding of salt-dependent pore structure modulation but also practices a simple, cost-effective, and potentially scalable technique for the production of coal-based HCs.

Structural DNA nanotechnology enables the self-organization of matter at the nanometer scale, but approaches to expand the inorganic and electrical functionality of these scaffolds remain limited. Developments in nucleic acid metallics have enabled the incorporation of site-specific metal ions in DNA duplexes and provide a means of functionalizing the double helix with atomistic precision. Here a class of 2D DNA nanostructures that incorporate the cytosine-Ag-cytosine (dC:Ag:dC) base pair as a chemical trigger for self-assembly is described. It is demonstrated that Ag-functionalized DNA can undergo programmable assembly into large arrays and rings, and can be further coassembled with guanine tetraplexes (G4). It is shown that 2D DNA lattices can be assembled with a variety of embedded nanowires at tunable spacing. These results serve as a foundation for further development of self-assembled, metalated DNA nanostructures, with potential for high-precision DNA nanoelectronics with nanometer pitch.

SnO prepared by chemical bath deposition (CBD) is among the most promising electron transport layers for enabling high efficiency, large area perovskite solar cells (PSCs). However, the uneven surface coverage of SnO and the presence of defects in the film and/or at the SnO/perovskite interface significantly affect the device performance. Herein, a multifunctional molecule of phosphorylcholine chloride (CP) is introduced to modulate the CBD growth of SnO and suppress the generation of defects. The agglomeration of SnO nanoparticles is hindered due to the electrostatic repulsion effect, leading to the formation of dense and conformal films with improved optical transmittance and electrical conductivity. Moreover, the defects both in SnO and at the interface of SnO/perovskite are successfully passivated and the energy band structure is well regulated, contributing to the suppression of nonradiative recombination and the improvement of electron transport. As a result, a remarkably high power conversion efficiency (PCE) of 24.04% is attained for PSCs processed in air ambient. The unencapsulated devices exhibit improved long-term stability, maintaining over 80% of their initial PCE after storing in air ambient for 1500 h or under one-sun illumination for 600 h.

The recent prediction of the new magnetic class, altermagnetism, has drawn considerable interest, fueled by its potential to host novel phenomena and to be utilized in next-generation spintronics devices. Among many promising candidates, rutile RuO is a prototypical candidate for realizing the prospects of altermagnetism. However, the experimental studies on RuO are still in the early stages. In this study, the magnetic responses in RuO film are investigated by the Planar Hall effect (PHE). By rotating the external field (H), the PHE exhibits twofold behaviors. Moreover, the planar Hall conductivity shows a nonlinear response to the H. These observed features in PHE resemble those in ferromagnet and topologically nontrivial systems, suggesting the field-induced magnetic response in rutile antiferromagnet. The work provides a strategy for detecting intriguing magnetic responses in altermagnetic materials, promoting further research in altermagnet-based spintronics and novel phenomena.

Clay-based 2D nanofluidics present a promising avenue for osmotic energy harvesting due to their low cost and straightforward large-scale preparation. However, a comprehensive understanding of ion transport mechanisms, and horizontal and vertical transmission, remains incomplete. By employing a multiscale approach in combination of first-principles calculations and molecular dynamics simulations, the issue of how transmission directions impact on the clay-based 2D nanofluidics on osmotic energy conversion is addressed. It is indicated that the selective and rapid hopping transport of cations in clay-based 2D nanofluidics is facilitated by the electrostatic field within charged nanochannels. Furthermore, horizontally transported nanofluidics exhibited stronger ion fluxes, higher ion transport efficiencies, and lower transmembrane energy barriers compared to vertically transported ones. Therefore, adjusting the ion transport pathways between artificial seawater and river water resulted in an increase in osmotic power output from 2.8 to 5.3 W m, surpassing the commercial benchmark (5 W m). This work enhanced the understanding of ion transport pathways in clay-based 2D nanofluidics, advancing the practical applications of osmotic energy harvesting.

Wide-bandgap perovskite sub-cells (WPSCs), one of the most crucial components of perovskite-based tandem solar cells (PTSCs), play a critical role in determining the performance of tandem devices. However, confined by the compromised crystallization properties of wide-bandgap perovskites, WPSCs exhibit significantly lower efficiency than their theoretical limit. In particular, for n-i-p structured all-inorganic WPSCs (AIWPSCs), severe nonradiative recombination due to the buried interface defects severely decreases the photovoltaic performance. Herein, an efficient propionate group (PA) based ionic liquid, methylamine propionate (MAPA), is introduced into the perovskite/electron-transport layer (ETL) interface to passivate the buried interface of AIWPSCs. The intense interaction between the PA and Pb-Pb dimer effectively heals the defects at the buried interface and facilitates a more homogeneous elemental distribution in the perovskite film. As a result, CsPbIBr-based AIWPSCs with a high power conversion efficiency (PCE) of 18.29% and open-circuit voltage (V) of 1.33 V are obtained, which illustrates the superiority of MAPA in optimizing the performance of AIWPSCs. Moreover, by integrating these AIWPSCs with small-bandgap organic solar cells (SOSCs), high performance n-i-p structured all-inorganic perovskite/organic tandem solar cells (AIPOTSCs) with a high PCE of 23.19% and V of 2.08 V are also achieved.

Recent studies show the importance of hydrogel geometry for various applications, such as encoding, micromachines, or tissue engineering. However, fabricating hydrogel structures with micrometer-sized features, advanced geometry, and precise control of porosity remains challenging. This work presents hierarchically structured hydrogels, so-called hydrogel patches, with internally deviating regions on a micron-scale. These regions are defined in a one-step, high-throughput fabrication process via stop-flow lithography. Between the specified projection pattern during fabrication, an interconnecting lower crosslinked and more porous hydrogel network forms, resulting in at least two degrees of crosslinking within the patches. A detailed investigation of patch formation is performed for two material systems and pattern variations, revealing basic principles for reliable patch formation. In addition to the two defined crosslinked regions, further regions are implemented in the patches by adapting the pattern accordingly. The variations in pattern geometry impact the mechanical characteristics of the hydrogel patches, which display pattern-dependent compression behavior due to predefined compression points. Cell culture on patches, as one possible application, reveals that the patch pattern determines the cell area of L929 mouse fibroblasts. These results introduce hierarchically structured hydrogel patches as a promising and versatile platform system with high customizability.

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has attracted wide attention in tumor treatment. However, the hypoxic tumor microenvironment and the heat shock proteins produced by tumor cells significantly reduce their efficacy. Developing effective phototherapy agents that have high reactive oxygen species generation efficiency and photothermal conversion efficiency (PCE) while simultaneously utilizing the hypoxic tumor microenvironment is of great importance. Here, a thienothiophene-benzopyran derivative, BTPIC4F-C10 is designed and synthesized, with near-infrared (NIR) absorption and fluorescence. Then the lipid nanoparticles (LipBFCA NPs) which encapsulated BTPIC4F-C10 in a phospholipid bilayer together with hypoxia-activated prodrug banoxanthrone (AQ4N) are constructed for NIR-II fluorescence imaging-guided synergistic PDT/PTT/chemotherapy and immune activation. Under 808 nm laser irradiation, LipBFCA NPs is a high singlet oxygen quantum yield of 20.2% and PCE of 78.8%. With ultra-high photon energy utilization efficiency of 99%, LipBFCA NPs is an excellent phototherapy effect. The hypoxic environment caused by phototherapy can further activate AQ4N to transform into chemically toxic AQ4 radicals to kill tumor cells. Moreover, phototherapy can induce immunogenic cell death, release tumor-associated antigens, and activate immune responses. This work provides a new way for the clinical application of fluorescence imaging in guiding tumor diagnosis and treatment.

Cerium oxide (CeO) exhibits application potential for the selective catalytic reduction of nitrogen oxides (NO) with NH (NH-SCR). The crystal facets and morphology of CeO have a vital impact on the catalytic performance of NH-SCR. However, the precise influence mechanisms on SCR activity remain elusive. In this work, CeO is successfully synthesized with three distinct crystal facets and nine diverse morphologies. This investigation involves a comprehensive blend of theoretical analysis and experiments, to gain profound insights into the underlying mechanisms governing the SCR catalytic activity concerning morphology and crystal facets. By closely integrating density functional theory (DFT) calculations, Ab initio thermodynamic analysis, SCR catalytic activity experiments, and X-ray photoelectron spectroscopy experiments, it is discovered that the concentration of surface-active oxygen (O) plays a pivotal role in determining the catalytic activity of CeO in SCR reactions, as opposed to factors like specific surface area or oxygen defect concentration. This experimental-theoretical joint study provides design principles of CeO catalysts for NO removal.

Direct ink writing (DIW) enables 3D printing of macroscopic objects with well-defined structures and compositions that controllably change over length scales of order 100 µm. Unfortunately, only a limited number of materials can be processed through DIW because it imparts stringent rheological requirements on inks. This limitation can be overcome for soft materials, if they are formulated as microparticles that, if jammed, fulfill the rheological requirements to be printed. By contrast, densely packed rigid microparticles with stiffnesses exceeding 2 MPa do not exhibit appropriate rheological properties that enable DIW. Here, an ink composed of up to 60 vol% rigid microparticles with core stiffnesses up to 50 MPa is introduced. To achieve this goal, rigid microparticles possessing soft hydrogel shells are produced. The 3D printed fragile granular structure is transformed into a load-bearing granular material through the formation of a 2nd network within the soft shells and in the interstitial spaces. The potential of these particles is demonstrated to be printed into intricate 3D structures, such as a trophy cup, or cast into flexible macroscopic photonic films.

Separation of benzene and cyclohexane is essential for obtaining high-purity cyclohexane in the chemical industry and for resource recovery from exhaust gas, but is one of the most challenging separation processes due to their highly similar boiling points and kinetic diameters. Herein, based on the isoreticular contraction strategy, a novel covalent organic framework (i.e., HFPB-TAB-COF) with kgd topological structure and average pore size of 5.70 Å, between the kinetic diameters of benzene (5.60 Å) and cyclohexane (6.10 Å), is synthesized for benzene/cyclohexane separation by pore confinement effect. HFPB-TAB-COF has the highest ideal adsorbed solution theory (IAST) selectivity of 36.0 for benzene/cyclohexane separation, and can produce 0.48 mmol g cyclohexane with purity of +99% from 50:50 (v:v) benzene/cyclohexane mixture under dynamic condition, higher than reported separation materials. Optimizing the pore size of COFs by isoreticular contraction strategy can trigger the pore confinement effect for better meeting the separation challenge in industry.

The unique surface properties of grafted polydimethylsiloxane (PDMS) chains, particularly their omniphobicity and low friction, are influenced by molecular structure and tethering density. Despite molecularly smoothness and homogeneity, these surfaces exhibit significant variability in wettability and contact angle hysteresis (CAH). This work uncovers the molecular structure of grafted PDMS chains. Grafted PDMS chains synthesized using a difunctional chlorosilane initiator, which exhibits CAH <2° on silicon wafers, adopt a brush-to-mushroom conformation with a molecular weight ≈7,800 g mol, a grafting density of 0.22 ± 0.4 chains nm, and a thickness of ≈3 nm. Each PDMS chain terminates with a silanol group, and ≈96% of substrate silanols remain unreacted. The presence of these terminal silanols is confirmed with time-of-flight secondary ion mass spectroscopy, as is their removal when exchanged for trimethylsilyl groups, both on the substrate and terminating the PDMS chains. Quartz crystal microbalance with dissipation measurements show that this "capping" procedure exchanges ≈1.5 silanols nm; capping occurs at the substrate and PDMS chain end. The findings suggest that grafted, capped PDMS chains of this molecular weight are able to achieve excellent omniphobic properties even when the majority of surface silanols remain unreacted, which may aid in the design of future omniphobic materials.

Metal-metal oxide hybrid materials, typically composed of metal nanoparticles anchored on metal oxides matrix, are devoted enormous attentions as famous heterogeneous catalysts. The interactions between noble metals and metal oxides as well as their interfaces have been proven to be the origin of their excellent catalytic performance. Deep understandings on the interactions between noble metals and metal oxides at atomic precision, thus to precisely assess their contributions to catalysis, can serve as basic principles for catalyst design. In recent years, polyoxometalates (POMs), which in principle can be regarded as atomically precise metal oxide clusters, have been shown to have strong affinity to noble metals, thus forming diverse kinds of POM-noble metal hybrid clusters. Their well-resolved atomically precise structures and hybrid nature promise them as ideal platforms to understand the interfaces and interactions between noble metals and metal oxides. In this review, metal-metal oxide interface is classified into different categories based on the different configurations of hybrid clusters, and aims to understand the interface structures and electronic correlations between POMs and noble metals at the atomic precision. Based on these basic understandings, the study provides the perspectives on the challenges and research efforts to be paid in the future.

The interaction between bacteria and nanomaterials, particularly from a physical or mechanical perspective, has emerged as a topic of significant interest in both science and medicine. Mechanobactericidal nanomaterials, which exert antimicrobial effects through purely physical mechanisms, hold promise as alternative strategies to combat bacterial resistance to traditional antibiotics. High-aspect-ratio nanoparticles and surface topographies are being engineered to enhance their mechanobactericidal properties. However, progress in this field is hindered by an incomplete understanding of how these materials induce mechanical cell death in bacteria. This review examines the role of atomic force microscopy (AFM) nanoindentation in quantifying forces required to rupture the bacterial cell wall. The reported values range from nN to a few tens of nN, depending on the type of bacterium and the experimental conditions used. The potential effect of AFM tip properties, loading speed, bacterial immobilization strategy, or environmental conditions on the measured rupture values are discussed. This perspective also highlights the complexities of modeling bacterial cell rupture and the importance of pressure as a parameter for standardizing results across experiments. Furthermore, the implications of these quantitative insights to understand the mechanisms of action of mechanobactericidal nanomaterials are discussed.

Semitransparent perovskite solar cells (PSCs) efficiently absorb light from both front and rear sides under illumination, and hence, PSCs have the potential for use in applications requiring bifacial or tandem solar cells. A facile method to fabricate semitransparent PSCs involves preparing a perovskite (PVSK) film on two transparent substrates and then laminating the substrates together. However, realizing high-performance laminated semitransparent PSCs is challenging because the imperfect contact at the PVSK interlayer results in void formation and partial degradation of PVSK. To address this issue, a halide-diffusion-assisted lamination (HDL) method is proposed. In the method, a controlled halide concentration gradient is used to effectively laminate the top and bottom PVSK layers. Semitransparent PSCs prepared through the HDL method (hereafter referred to as HDL-PSCs) exhibited a power conversion efficiency (PCE) of 18.93%. In particular, an HDL-PSC exhibited higher thermal stability, maintaining its initial PCE for over 1200 h at 85 °C.

Developing and fabricating a heterogeneous catalyst for efficient formic acid (FA) dehydrogenation coupled with CO hydrogenation back to FA is a promising approach to constructing a complete CO-mediated hydrogen release-storage system, which remains challenging. Herein, a facile two-step strategy involving high-temperature pyrolysis and wet chemical reduction processes can synthesize efficient pyridinic-nitrogen-modified carbon-loaded gold-palladium alloy nanodots (AuPd alloy NDs). These NDs exhibit a prominent electron synergistic effect between Au and Pd components and tunable alloy-support interactions. The pyridinic-N dosage in carbon substrate improves the surface electron density of the alloy catalyst, thus regulating the chemical adsorption of FA molecules. Specifically, the engineered AuPd/CN demonstrates an outstanding room-temperature FA dehydrogenation efficiency, achieving ≈100% conversion and an initial turnover frequency (TOF) of up to 9049 h. The versatile AuPd alloy NDs also show the ability to convert CO, one of the products of FA dehydrogenation, into FA (formate) with a 90.8% yield under mild conditions. Moreover, in-depth insights into the unique alloyed microstructure, structure-activity relationship, key intermediates, and the alloy-driven five-step reaction mechanism involving the rate-determining step of C─H bond cleavage from critical *HCOO species via D-labeled isotope, in situ infrared spectroscopy, and theoretical calculations are investigated.

Misuse of antibiotics and pesticides has led to hazardous effects on human health, livestock, agriculture, and aquaculture, which urges researchers to find simple, rapid, efficient, and cost-effective methods for quick on-site analysis of these organic pollutants with functional materials. Herein, a 2D chemically robust MOF: IITKGP-71, {[Cd(MBPz)(2,6-NDC)]·2HO} is strategically developed with ease in scalability and exploited as dual sensors toward the toxic antibiotic and pesticide detection via luminescence quenching in aqueous medium. The framework displays exceptional chemical robustness in water for 3 months, in an open atmosphere over 2 months, and wide range of aqueous pH solution (pH = 3-12) for a day. IITKGP-71 can selectively quench the nitrofuran antibiotics (NFZ and NFT) and organochlorine pesticide DCN while remaining unaffected by other interfering antibiotics and pesticides, respectively. An excellent trade-off between high effectivity (high K) and high sensitivity (low LOD) was achieved for the targeted analytes. The easy scalability, high chemical stability, fast responsivity, multi-responsive nature, recyclability with outstanding structural stability made this framework viable in playing a crucial role in safeguarding aquatic ecosystems and public health from the hazardous effects of antibiotics and pesticides.

Developing advanced and economically viable technologies for the capture and utilization of carbon dioxide (CO) is crucial for sustainable energy production from fossil fuels. Converting CO into valuable chemicals and fuels is a promising approach to mitigate atmospheric CO levels. Among various methods, photocatalytic reduction stands out for its potential to reduce emissions and produce useful products. Here, novel perovskite ZnMoFeO (ZMFO) nanosheets are presented as promising semiconductor photocatalysts for CO reduction. Experimental results show that ZMFO has a narrow bandgap, exceptional visible light response, large specific surface area, high crystallinity, and various surface-active sites, leading to an impressive photocatalytic CO reduction activity of 24.87 µmolgh and strong stability. Theoretical calculations reveal that CO conversion into CO and CH on the ZMFO surface follows formaldehyde and carbine pathways. This study provides significant insights into designing innovative perovskite oxide-based photocatalysts for economical and efficient CO reduction systems.