Lithium metal batteries paired with high-voltage nickel-rich cathodes offer high energy density. However, stable operation at ultra-high voltages (>4.5 V) requires suppression of severe interfacial degradation. Herein, difluoropyridine-boronic acid (DFPBA) is proposed as a multifunctional electrolyte additive to construct synergistic electrode/electrolyte interphases (EEIs). DFPBA preferentially decomposes to form a dense hybrid cathode electrolyte interface (CEI) comprising LiF, Li3N and LiBxOy. Simultaneously, DFPBA optimizes the solid electrolyte interphase (SEI) on lithium metal anodes, enhancing structural integrity. The lone-pair electrons of nitrogen (N) atoms in DFPBA suppress HF formation, while boric acid derivatives reinforce EEI mechanical stability. Consequently, the rapidly formed CEI at 4.7 V enables the Li||NCM622 cells to achieve 80.4% capacity retention after 400 cycles, surpassing cells without DFPBA (45.5%). This study demonstrates the exceptional electrochemical performance achieved with NCM622 cathodes at high voltages, providing pivotal insights for developing advanced electrolytes targeting demanding energy storage systems.

The escalating demand for lithium-ion batteries emphasizes the urgency of developing cobalt- and nickel-free cathodes ascribed to the high cost of these two metals. LiMnxFe1-xPO4 (LMFP) emerges as a promising candidate due to high operating voltage compared to LiFePO4 while suffering from inferior kinetics and cycling instability. This study demonstrates that precise pH control during the solvothermal process is pivotal for optimizing the LMFP/C microstructure and performance; furthermore, the mechanism of morphology evolution along with pH value and reaction duration is summarized. LiMn0.7Fe0.3PO4/C composites synthesized under varied pH conditions were thoroughly characterized and electrochemically evaluated. Results reveal that a moderately acidic environment (pH 4) facilitates the formation of a unique nanoflower architecture composed of (010)-oriented nanosheets with a highly graphitized carbon coating and minimal antisite defects after calcination. This optimal structure endows LiMn0.7Fe0.3PO4/C composite sample LMP/C-P4-24 with superior Li+ diffusion kinetics and charge-transfer efficiency, enabling a high discharge capacity (151.5 mAh g-1 at 1 C), outstanding cycling stability (96.1% retention after 500 cycles), and excellent rate capability (110.3 mAh g-1 at 10 C). In contrast, synthesis at higher pH induces structural disorder and inferior carbon quality with rapid performance degradation. This work establishes pH-mediated structural control as a powerful strategy for high-performance, resource-conscious, Mn-rich LiMn0.7Fe0.3PO4 cathode materials.

Carrier recombination is a significant impediment to efficient charge separation, thereby severely limiting the performance of photocatalytic systems. In this study, we feature an innovative internal energy cycling mechanism through the non-radiative fluorescence resonance energy transfer (FRET) between perovskite and MXene, to exploit the energy released by carrier recombination for enhancing H2 evolution rate. Consequently, a rapid H2 evolution rate of 2394 µmol g-1 h-1 under 1.5 AM simulated sunlight, from the composite of FAPbI3/MXene/Pt, was acquired, which is more than one order of magnitude higher than that of FAPbI3/Pt (64 µmol g-1 h-1). The innovative approach of FRET induced internal energy cycling will open up opportunities to design other novel heterogeneous catalytic materials and promote their application potential in various catalytic fields.

Interlayer and defect engineering significantly affects the electrical conductivity and electromagnetic interference (EMI) shielding of Ti3C2Tx MXene. Previous studies have prioritized the size of the intercalant over its synergy with chemical affinity, limiting the elucidation of the intercalation mechanism and the precise control of the interlayer spacing (d-spacing). Herein, we synthesize MXene aerogels with a tunable d-spacing and defect density using a series of amine molecules of different sizes and chemical affinities as intercalants and cross-linkers. Particularly, the intercalation of p-phenylenediamine (PPD) increases the d-spacing of MXene from 0.960 to 1.642 nm. Simultaneously, the increased d-spacing contributes to an increased defect density within the Ti-Ti layer. Hence, the PPD@MXene aerogel exhibits reduced surface electric field intensity and increased internal polarization loss, resulting in absorption-dominated EMI shielding. The absorptivity reaches 0.92, far exceeding the reported shielding materials, with a shielding effectiveness of 50.4 dB. This study provides a theoretical foundation and preliminary guidance for the development of interlayer-engineered MXene shielding materials.

Enhancing the tolerance of Li-ion batteries (LIBs) to high charging voltage and extreme climates is pivotal for further widespread application. Nevertheless, practical capacity utilization is severely constrained by interfacial parasitic reactions, electrolyte consumption, and sluggish kinetics. Modulating the electrode/electrolyte interphase (EEIs) with functional additives is a favorable approach. Herein, a novel multifunctional electrolyte additive, diethyl [4-(Trifluoromethyl) benzyl] phosphonate (DBP) containing fluorine, phosphate, and phenyl groups is proposed to simultaneously modify both cathode and anode of LIBs. The preferential decomposition of DBP facilitates the formation of a mechanically robust and ionically conductive EEIs. The DBP-derived cathode-electrolyte interphase (CEI) is capable of suppressing transition metal-ion dissolution and cation disorder. Moreover, DBP exhibits multifunctional benefits, including accelerating Li+ transport, scavenging free radicals, and curbing the hydrolysis of LiPF6. Therefore, with optimized DBP additive, Li||NCM622 cell achieves advanced performance under harsh conditions, e.g. high temperature (60 degrees C), low temperature (-10 degrees C), and high cut-off voltage (4.6 and 4.8 V). Furthermore, the Li||Li symmetric cell cycles for over 450 h at 0.5 mA cm-2/0.5 mAh cm-2 stably, which demonstrates the potential to be applied into practical LIBs.

The century-old inverted Keggin ion has been revisited in an effort to unleash its potential in the structural engineering and functional development of polyoxomolybdates (POMos). Over the past hundred years, attempts to program the metal-oxo scaffold of inverted Keggins have been conducted continually but without any success. In this work, a structurally inert, inverted Keggin-type POMo could finally be altered by means of a binary heterogroup-templated approach, resulting in the successful isolation of two lacunary species. The local structure and charge distribution of these species are adjustable, and hence they serve as available building blocks for the subsequent controlled assembly of a CeIII-incorporated derivative. From the plenary to the lacunary, the enclosed structure of the inverted Keggin has been opened up significantly, resulting in less steric hindrance, along with a transition from an electron neutral species to a negatively charged species. Owing to these beneficial properties, the emerging defect-containing polyanions demonstrated outstanding Lewis acid-base catalytic activity in the high efficiency production of pyrazoles.

The development of high-performance non-platinum catalysts remains a key challenge for the practical application of anion-exchange membrane fuel cells due to the sluggish kinetics response of the hydrogen oxidation reaction (HOR) in alkaline electrolytes. Herein, we report an outstanding HOR electrocatalyst using a facile one-step method with the two-dimensional double transition metal MXene (Mo2TiC2Tx) as a carrier mixed with metallic ruthenium and Cr(OH)(x) clusters (Ru-Cr(OH)x/MXene). Specifically, the as-prepared Ru-Cr(OH)(x)/MXene electrocatalyst exhibits a high apparent kinetic current (j(k)) of 18.32 mA cm(-2) and exchange current (j(0)) of 1.64 mA cm(-2) at an overpotential of 50 mV, respectively, which are 4.74 and 1.46 times as high as those of Pt/C catalyst. Additionally, mechanism experiments indicated that the Ru-Cr(OH)(x)/MXene electrocatalyst could attenuate the adsorption of hydrogen intermediate (H-ad) and enhance the adsorption of hydroxyl species (OHad) to promote CO oxidation, which resulted in a significant increase in the HOR activity and enhanced tolerance to CO. Furthermore, combining theoretical studies via density functional theory calculations, our work confirm that the interaction effect of each components of Ru-Cr(OH)(x)/MXene can optimize the binding energy of the H-ad and OHad for the HOR. This work develops a new approach to design of HOR electrocatalyst with MXene-based materials.

Self-assembly is a natural way for primitive things to grow on earth. For long, mankind has been attracted by the mechanism of such assembly processes, in an attempt to manipulate the outcome by whatever chemical forces available. The study on molecular building blocks, with an emphasis on lacunary polyoxometalates (l-POMs), delivers a unique perspective on the formation of natural and synthetic phases (e.g., minerals and nanomachines). The tunability of structure, composition, and physicochemical property confers a competitive edge on l-POMs in the design and fabrication of materials with desired functions. In this contribution, we provide a structural overview of l-POMs that covers not only the classical members of polyoxotungstates, -molybdates, -vanadates, -niobates, and -tantalates, but also the recently emerged non-classical counterparts of polyoxotitanates, -ferrates, and -palladates also. The evolution paths of l-POMs in the course of isomerization, transformation, and fusion are summarized and proposed. The empirical rules that supervise structural switches are discussed as well, in an effort to mature the design of POM-based materials in a controlled manner.

glucose sensor modified by gold nanoparticles/multi-walled carbon nanotubes/Prussian blue (AuNPs/MWCNTs/PB) with high sensitivity and low limit of detection (LOD) was constructed through the characteristics of chemical crosslinking and high charge transfer. The interface between MWCNTs and PB particles accelerated the generation and transfer of induced charges, and more effectively induced the substrate glucose. The evaluation of electrochemical sensing performance was characterized by cyclic voltammetry (CV) and time-current (IT) curve. In phosphate buffer solution, the electrochemical sensing range of the sensor for glucose is 7e-5-9 mM. The corresponding sensitivity and LOD are 13.38 mu A/mM/cm(2) and 70 nM, respectively. The working mechanism of the sensor is analyzed and explained by theoretical simulation. In addition, we evaluated the selectivity, stability, and reproducibility of the sensor. A comprehensive comparison has been driven to the performance of glucose sensors prepared with various composite materials, including PB, MWCNTs/PB, AuNPs/PB, and AuNPs/MWCNTs/PB. To sum up, the prepared AuNPs/MWCNTs/PB glucose sensor has the advantages of simple preparation, high sensitivity, and low LOD. It has practical application prospects in glucose sensing.

A rigid nicotinate-modified lanthanide-substituted selenotungstate [H2N(CH3)2]6Na3H[La4SeW8(H2O)16(nica)2O28][SeW9O33]232H2O (1, Hnica = nicotinic acid) was synthesized and consists of two trivacant Keggin [B-alpha-SeW9O33]8- fragments and one unusual [SeW4O18]8- fragment bridged by a heterometallic [La4W4(H2O)16(nica)2O28]18- cluster. In the heterometallic cluster, two carboxyl O atoms in two nicotinate ligands directly coordinate with two W atoms in a stable C-O-W-O-W-O six-membered ring fashion. According to its catalase-like activity, 1 was utilized to catalyze the oxidation of 3,3 ',5,5 '-tetramethylbenzidine (TMB) by H2O2 to produce blue oxidized TMB (ox-TMB), which can be used to establish a colorimetric sensing method for the detection of ascorbic acid. This work not only provides a promising platform for detecting H2O2 and ascorbic acid but also expands the application potential of polyoxometalate-based materials in biological and clinical analyses.

Sensitive and stable perovskite X-ray detectors are attractive in low-dosage medical examinations. The high sensitivity, tunable chemical compositions, electronic dimensions, and low-cost raw materials make perovskites promising next-generation semiconductors. However, their ionic nature brings serious concerns about their chemical and water stability, limiting their applications in well-established technologies like crystal polishing, micro-processing, photolithography, etc. Herein we report a one-dimensional tryptamine lead iodide perovskite, which is stable in water for several months as the strong cation-π interactions between organic cations. The one-dimensional and two-dimensional tryptamine lead iodide perovskite tablets are switchable through thermal-annealing or water-soaking treatments to relax microstrains. The water-stable and microstrain-free one-dimensional perovskite tablets yield a large sensitivity of 2.5 × 10 6 μC Gy air −1 cm −2 with the lowest detectable dose rate of 5 nGy air s −1 . Microelectrode arrays are realized by surface photolithography to construct high-performance X-ray flat mini-panels with good X-ray imaging capability, and a record spatial resolution of 17.2 lp mm −1 is demonstrated.

Advanced photodetectors with intelligent functions are expected to take an important role in future technology. However, completing complex detection tasks within a limited number of pixels is still challenging. Here, we report a differential perovskite hemispherical photodetector serving as a smart locator for intelligent imaging and location tracking. The high external quantum efficiency (~1000%) and low noise (10 −13 A Hz −0.5 ) of perovskite hemispherical photodetector enable stable and large variations in signal response. Analysing the differential light response of only 8 pixels with the computer algorithm can realize the capability of colorful imaging and a computational spectral resolution of 4.7 nm in a low-cost and lensless device geometry. Through machine learning to mimic the differential current signal under different applied biases, one more dimensional detection information can be recorded, for dynamically tracking the running trajectory of an object in a three-dimensional space or two-dimensional plane with a color classification function.

Metal halide scintillators serve as promising candidates for X-ray detection due to their high attenuation coefficients, high light yields, and low-cost solution-processable characteristics. However, the issues of humidity/thermal quenching and mechanical fragility, remain obstacles to the broad and diversified development of metal halide scintillators. Here, this work reports a lead-free, water-stable, stretchable, and self-healing (ethylenebis-triphenylphosphonium manganese (II) bromide (C38H34P2)MnBr4 organogel scintillator that meets X-ray imaging in complex scenarios. The robust organogel scintillator can be stretched with elongation up to 1300% while maintaining the scintillation properties. Activated by the dynamic hydrogen bonds and coordination bonds design, the organogel scintillator exhibits excellent self-healing properties at room temperature to alleviate the vignetting problem of the rigid scintillator films, the X-ray imaging resolution can reach 16.7 lp mm-1. The organogel scintillator can also realize flexible and self-healing X-ray imaging in water, providing a design path for portable devices in harsh conditions.

A reexamination of the structural constraints on the amino acid-functionalized heteropolymolybdates has afforded four polyanions,namely the double-layer [（SeO 3 ） 2 Mo 12 O 36 （CH 3 COO） 3 ] 7- （1）,[（SeO 3 ） 1.3 （HPO 3 ） 0.7 Mo 12 O 36 （NH 3 CH 2 COO） 3 ] 4- （2）,[（SeO 3 ） 1.4 （HPO 3 ） 0.6 Mo 12 O 36 （LNH 3 C 2 H 3 OHCOO） 3 ] 4- （3）,and the mono-layer [（SeO 3 ）-Mo 6 O 18 （L-NH 3 C 2 H 3 OHCOO） 3 ] 2- （4）,which were crystallized as the hydrated ammonium salts,

Bestowed with abundant surface terminations and good electrical conductivity, transition-metal carbides/nitrides (MXene) have potential applications as gas sensors. Here, Ti3C2Tx-HF and Ti3C2Tx-HCl MXenes were functionalized with polyethyleneimine/polyethylene-glycol (PEI/PEG) to form PEI/PEG/Ti3C2Tx-HF (P/P/Ti-1) and PEI/PEG/Ti3C2Tx-HCl (P/P/Ti-2) composites for gaseous CO2 detection at room temperature. The morphologies and elemental compositions indicated that Ti3C2Tx-HCl more easily combined with PEI/PEG than did Ti3C2Tx-HF. The response of the P/P/Ti-2 sensor to 2000 ppm CO2 was six-fold better than that of the P/P/Ti-1 sensor. In addition, the P/P/Ti-2 sensor exhibited higher selectivity and good stability. The enhanced P/P/Ti-2 sensing was attributed to heterojunctions formed at the interfaces between Ti3C2Tx-HCl and PEI/PEG because of the thinly and fully covered PEI/PEG layer on the Ti3C2Tx-HCl via abundant -OH functional groups. This was confirmed by current-voltage curves, and good Ti3C2Tx conductivity. A portable wireless CO2 indoor monitoring system based on the P/P/Ti-2 sensor was demonstrated. These results provide a better understanding of the physical and gas-sensing properties of Ti3C2Tx materials.

Two-dimensional (2D) transition metal carbides (MXene) have attracted great attention for device applications due to their unique structures and excellent properties, such as high electrical conductivity and abundant functional groups on the surface. However, gas sensors based on Ti3C2Tx MXene have the problems of high detection limit and poor long-term stability. Herein, we report a simple method to prepare Ti3C2Tx/Ti3AlC2 planar composite gas sensing materials using high molar ratio of HCl and LiF with Ti3AlC2 as a framework. The Ti3C2Tx/Ti3AlC2 planar composite gas sensor has a high sensitivity, good selectivity and low detection limit for NH3, which can detect 50 ppb (1.2%) at room temperature (25°C). Furthermore, the gas sensor has good repeatability and long-term stability. After 120 days, the response of the gas sensor to 500 ppb of NH3 fluctuated little due to the Ti3AlC2 as a framework. The superior performances can be attributed to the special heterojunction between Ti3C2Tx and Ti3AlC2 and the high proportion of -O and -OH functional groups on the surface of Ti3C2Tx/Ti3AlC2 composite. This study provides an important reference for the realization of high performance NH3 sensing by Ti3C2Tx.

The hydrogen evolution reaction (HER) is a key step in electrocatalytic water splitting, so developing an efficient and robust pH-universal HER electrocatalyst is highly desirable. Here, we report a facile electrodeposition method to synthesize two-dimensional Mo2TiC2Tx MXene-supported Ru nanoclusters immobilized on a Ni-NiO heterostructure (Ru/Ni-NiO/Mo2TiC2Tx) for an enhanced pH-universal HER. As expected, the as-prepared Ru/Ni-NiO/Mo2TiC2Tx demonstrated outstanding HER performance in full-pH range electrolytes, including diminutive overpotentials (eta(10)) of 41, 49, and 76 mV at a current density of 10 mA cm(-2), low Tafel slopes of 28, 62, and 68 mV dec(-1) in alkaline (1.0 M KOH), acidic (0.5 M H2SO4), and neutral (1.0 M phosphate-buffered solution, pH = 7) electrolytes, respectively. These results outperform the other reported nonprecious-metal electrocatalysts and multimetallic alloy electrocatalysts in the same conditions. Moreover, the operando electrochemical impedance spectroscopy measurements were used to estimate the electrocatalytic HER kinetics of Ru/Ni-NiO/Mo2TiC2Tx, indicating the Mo2TiC2Tx MXene-supported Ni-NiO heterostructure and Ru nanoclusters as excellent functional components in the electrocatalyst and thereby creating a fast charge-transfer kinetics for the HER. This work provided a feasible and convenient avenue to develop a robust and cost-effective pH-universal HER electrocatalyst through an electrochemical method using the Mo2TiC2Tx MXene as supports.

Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals interlayer interaction of two-dimensional materials.Here,we address this challenge by preparing an origami accordion structure of ultrathin two-dimensional graphitized carbon nitride(oa-C3N4)with rich vacancies.This novel structured oa-C3N4 shows exceptional photocatalytic activity for the CO2 reduction reaction,which is 8.1 times that of the pristine C3N4.The unique structure not only prevents restacking but also increases light harvesting and the density of vacancy defects,which leads to modification of the electronic structure,regulation of the CO2 adsorption energy,and a decrease in the energy barrier of the carbon dioxide to carboxylic acid intermediate reaction.This study provides a new avenue for the development of stable high-performance two-dimensional catalytic materials.

Although two-dimensional (2D) materials with ultrathin geometry and extraordinary electrical attributes have attracted substantial concern, exploiting new-type 2D materials is still a great challenge. In this work, an unprecedented single-layer pure polyoxometalate (POM) 2D material (2D-1) was prepared by ultrasonically exfoliating a one-dimensional (1D)-chain heterometallic crystalline germanotungstate Na4[Ho(H2O)6]2[Fe4(H2O)2(pic)6Ge2W20O72]·16H2O (1) (Hpic = picolinic acid). The 1D polymeric chain of 1 is assembled from particular {Ge2W20}-based [Fe4(H2O)2(pic)6Ge2W20O72]10- segments through bridging [Ho(H2O)6]3+ cations. 2D-1 is formed by π-π interaction driving force among adjacent 1D polymeric chains of 1. Also, the peroxidase-mimicking properties of 2D-1 toward detecting H2O2 were evaluated and good detection result was observed with a limit of detection (LOD) of 58 nM. Density functional theory (DFT) calculation further confirms that 2D-1 displays outstanding catalytic activity and active sites are located on Fe centers and Hpic ligands. Under the catalysis of uricase, uric acid can be transformed to allantoin and H2O2, and then, H2O2 oxidizes TMB to its blue ox-TMB in the presence of 2D-1 as a catalyst. Then, we utilized this cascade reaction to detect uric acid, which also exhibits prominent results. This research opens a door to prepare ultrathin pure POM 2D materials and broadens the scope of potential applications of POMs in biology and iatrology.