Two-dimensional Layer Structure Research Articles

Ultra-thin SnS2 nanosheets grown on carbon nanofibers with high-performance in sodium-ion energy storage

SnS2 with two-dimensional layered structure has great application promising in the energy storage system due to its super high theoretical capacity. However, the serious volume expansion and low intrinsic conductivity are difficult to meet the commercial application of SnS2 in sodium-ion batteries (SIBs). Herein, SnS2/CNF was successfully prepared by simple electrospinning technique and hydrothermal method. Based on the synergistic effect between ultra-thin nanosheets and carbon nanofibers (CNF), the anode material not only shortened the path of electron transport, but also accelerated the sodium ion reaction kinetics, thus showed outstanding stability and reversibility SIBs. The SnS2/CNF displayed the excellent rate properties (352 mAh g-1 at 5 A g-1) as well as stable long term cycle performance (338 mAh g-1 at 3 A g-1 after 500 cycles). Furthermore, the SnS2/CNF//AC sodium-ion hybrid capacitor (SIHCs) exhibits excellent energy density and power density of 97 Wh kg-1/54 W kg-1. The capacity retention is 81 % after 2500 cycles at 1 A g-1. The SIHCs could light up to 100 LEDs easily, which thus exhibited great practical application potential in energy storage device.

Synthesis, crystal structures and fluorescence recognition properties of two novel chiral coordination compounds based on alanine derivate

Two novel chiral coordination compounds {[Cd(D-pmala)(2,2′-bipy)(H2O)]⋅1·25H2O}n (1), {[Pb4(D-pmala)4(5,5′-DM-2,2′-bipy)4(H2O)2]⋅7H2O}n (2) (D-pmala = N-(4-carboxyl) benzoyl-d-alanine, 2,2′-bipy = 2,2′-Bipyridine, 5,5′-DM-2,2′-bipy = 5,5′-Dimethyl-2,2′- Bipyridine) have been successfully synthesized under hydrothermal conditions. Their structures were identified using single-crystal X-ray crystallography and characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and solid-state circular dichroism spectra. Crystallographic analysis indicate that compound 1 features a "Z"-shaped one-dimensional chain structure, which further extends into three-dimensional supramolecular architectures through hydrogen-bonding interactions. Compound 2 displays a two-dimensional layer structure, a two-dimensional double-layer network structures is further formed through the hydrogen-bonding interactions. Moreover, The fluorescence recognition properties of compound 1 indicate that it is highly selective in detecting Cu2+ ions and tyrosine (Tyr) enantiomers in aqueous solutions, which indicates that compound 1 can be expected to be a bifunctional fluorescent recognition sensor to detect metal ions and amino acid enantiomers.

Structural phase transition and potential superconductivity initiated by pressure-driven in 1T–CrSe2

The exploration of the superconducting properties of antiferromagnetic parent compounds containing transition metals under pressure provides a unique idea for finding and designing superconducting materials with better performance. In this paper, the close relationship between the possible superconductivity and structure phase transition of the typical van der Waals layered material 1 T–CrSe2 induced by pressure is studied by means of electrical transport and x-ray diffraction for the first time. We introduce the possibility of pressure-induced superconductivity at 20 GPa, with a critical T c of approximately at 4 K. The superconductivity persists up to the highest measured pressure of 70 GPa, with a maximum T c ∼ 5 K at 24 GPa. We observed a structure phase transition from P-3 m1 to C2/m space group in the range of 9.4–11.7 GPa. The results show that the structural phase transition leads to the metallization of 1 T–CrSe2 and the further pressure effect makes the superconductivity appear in the new structure. The material undergoes a transition from a two-dimensional layered structure to a three-dimensional structure under pressure. This is the first time that possible superconductivity has been observed in 1 T–CrSe2.

Zn, Cd and Cu Coordination Polymers for Metronidazole Sensing and for Ullmann and Chan-Lam Coupling Reactions.

Five compounds, [Zn(bpe)1/2(BPTA)H2O]·H2O (1); [Zn(bpe)(BPTA)] (2); [Cd(bpe)(BPTA)H2O] (3); [Cd(BPTA)(bpmh)]·2H2O (4); and Cu(BPTA)(bpmh)1.5(H2O)]·H2O (5) were prepared employing 2,5-bis(prop-2-yn-1-yloxy)terephthalic acid (2, 5 BPTA) as the primary ligand and 1,2-di(pyridin-4-yl)ethane (4, 4' bpe) (1-3) and 1,2-bis(pyridin-3-ylmethylene)hydrazine (bpmh) (4-5) as the secondary ligands. Single crystal studies indicated that the compounds 1, 3 and 5 have two-dimensional layer structures and compounds 2 and 4 three-dimensional structures. The luminescence behaviour of the compounds 2 and 3 were explored for the sensing of metronidazoleboth in aqueouos solution as well as simple paper strips. The Cu compound 5 loses the coordinated water molecule at 100 °C without any structural change, which was examined towards the Lewis acidic character by carrying out the Ullmann type C-C homocoupling reaction of the aromatic halide compounds. The compounds, 4 and 5, also have the Lewis basic functionality arising out the =N-N=, aza groups. The bifunctional nature of the MOF was explored towards the Chan-Lam coupling reaction between phenyl boronic acid and aniline derivatives in the ethanol medium. In both the catalytic reactions, good yields and recyclability were observed. The present studies illustrated the rich diversity that the transition metal containing compounds exhibit in extended framework structures.

Research Progress on Ammonia Sensors Based on Ti3C2Tx MXene at Room Temperature: A Review.

Ammonia (NH3) potentially harms human health, the ecosystem, industrial and agricultural production, and other fields. Therefore, the detection of NH3 has broad prospects and important significance. Ti3C2Tx is a common MXene material that is great for detecting NH3 at room temperature because it has a two-dimensional layered structure, a large specific surface area, is easy to functionalize on the surface, is sensitive to gases at room temperature, and is very selective for NH3. This review provides a detailed description of the preparation process as well as recent advances in the development of gas-sensing materials based on Ti3C2Tx MXene for room-temperature NH3 detection. It also analyzes the advantages and disadvantages of various preparation and synthesis methods for Ti3C2Tx MXene's performance. Since the gas-sensitive performance of pure Ti3C2Tx MXene regarding NH3 can be further improved, this review discusses additional composite materials, including metal oxides, conductive polymers, and two-dimensional materials that can be used to improve the sensitivity of pure Ti3C2Tx MXene to NH3. Furthermore, the present state of research on the NH3 sensitivity mechanism of Ti3C2Tx MXene-based sensors is summarized in this study. Finally, this paper analyzes the challenges and future prospects of Ti3C2Tx MXene-based gas-sensitive materials for room-temperature NH3 detection.

Metal-induced assembly of two novel MOFs: Sensitive fluorescence sensing properties and insights into mechanisms

Two new MOFs, namely, [Pb2(2-CPP)2(H2N-bpdc)]n (1) and [Cd(3-CPP)2]n (2), have been prepared by using N- and O-donor ligands and metal ions Pb2+, Cd2+ under hydrothermal conditions. The single-crystal X-ray diffraction analysis was used to measure the crystal structure. The complex 1 is one-dimensional chain structures, and it can further form two-dimensional and three-dimensional supramolecular structures through π-π stacking. The complex 2 is a two-dimensional layered structure, which can form three-dimensional supramolecular structure through π-π interaction. The synthesized MOFs exhibit ligand-based luminescence, which can be attributed to the coordination effect. Due to its excellent fluorescence properties, complex 2 can be used for selective and sensitive detection of nitro aromatic compounds (NAC) and metal ions. The results show that the complex 2 could quickly detect Cr2O72−, nitrobenzene and Fe3+by fluorescence quenching, and had good anti-interference and cycle stability, so it was a potential chemical fluorescence sensing material. The identification mechanism of 2 is discussed by electron transfer analysis method and density functional theory (DFT) calculation.

Synthesis, crystal structure, photoelectric and photocatalytic properties of (C4H14N2)0.5Cu2SbSe3 with a two-dimensional layered structure

A selenoantimonate (C4H14N2)0.5Cu2SbSe3 (1) (C4H12N2 = 1, 4-butanediamine) was synthesized by solvothermal synthesis using 1, 4-butanediamine as solvent. By single-crystal X-ray diffraction, compound 1 has a two-dimensional (2-D) layered structure composed of a protonated organic amine [(C4H14N2)0.5]+ and an anionic layer [Cu2SbSe3]- containing the 6-membered rings (6-MR) Cu2SbSe3 and the 10-membered rings (10-MR) Cu3Sb2Se5. Solid-state UV-diffuse reflectance analysis showed that 1 has a band gap value of 1.85 eV, indicating its potential semiconducting properties. This paper studied the photodegradation properties of selenoantimonate containing the transition metal Cu for the first time, and found that its degradation rate methylene blue (MB) was 68.5 %. In addition, a series of characterizations were also performed.

A novel strategy for flood flow Prediction: Integrating Spatio-Temporal information through a Two-Dimensional hidden layer structure

In recent years, neural network models have been extensively applied in flood prediction due to their superior performance. However, most studies aimed at enhancing models have simply stacked basic models, overlooking the need for designs specific to the physical attributes of hydrological data. While stacking basic models can enhance flood prediction to a degree, they often introduce significant unnecessary complexity redundancy. Moreover, improvement strategies are challenging to generalize across different models. To address this issue, a widely applicable Two-Dimensional Hidden Layer (Td) architecture is proposed. Unlike single hidden layer architectures, this design specifically tackles hydrological data’s spatiotemporal characteristics. Discretizing spatiotemporal information in flood and rainfall data yields an abstract, two-dimensional representation of the hydrological data to enhance the model’s ability to utilize hydrological information. Using a Td structure instead of the single hidden layer in Recurrent Neural Network (RNN), Long Short-Term Memory (LSTM), Bidirectional Long Short-Term Memory (BiLSTM), and Convolutional Neural Network (CNN), the TdRNN, TdLSTM, TdBiLSTM, and TdCNN models are developed to assess the novel structure’s impact on foundational models. Experiments were conducted using empirical flood process data from the LouDe Station in Shandong, China, and the NingXiang Station in Hunan, China. The results indicate that, compared to benchmark models, network models incorporating a Td structure exhibit superior adaptability across various lead times. For instance, at the LouDe Station, with a one-hour lead time, the TdCNN model showed improvements in the Nash-Sutcliffe Efficiency Coefficient (NSE), Kling-Gupta Efficiency Coefficient (KGE), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE) performance metrics by 26.24%, 33.48%, 62.51%, and 56.88%, respectively, compared to the CNN model. The new models also demonstrated significant performance enhancements under other conditions. The experimental results demonstrate that the Td structure is an effective and versatile model improvement strategy. It enhances the prediction accuracy by strengthening the model’s ability to utilize information. This study may contribute to the development of a flood prediction system and provide data to support subsequent reservoir scheduling and disaster mitigation planning.

Zero-valent iron-loaded Ti3C2-MXene activated by persulfate for the degradation of tetracycline hydrochloride: Efficiency and mechanism

The unique two-dimensional "sandwich" structure and excellent surface chemistry of Ti3C2-MXene show great potential for environmental treatment. In this paper, a novel degradant, Ti3C2-MXene was modified by zero-valent iron (Fe0) composites (Fe0/Ti3C2-MXene) were prepared, which could successfully degrade tetracycline hydrochloride (TC) under sodium persulfate (PDS) conditions. Characterization methods such as SEM, XRD, and XPS demonstrated that Fe0/Ti3C2-MXene still retained the two-dimensional layered structure of Ti3C2-MXene, and the Fe0 nanoparticles were successfully attached to the surface and interlayers of Ti3C2-MXene. Meanwhile, the effects of catalyst dosage, PDS dosage, initial concentration, pH, and coexisting anions and cations on the degradation were investigated. The results indicated that the degradation of TC (80 mL, 20 mg/L) by 2 mg of Fe0/Ti3C2-MXene and 10 mg of PDS under 25 °C and pH=4 could reach 80 % within 2 min. There is a synergistic effect of adsorption and oxidative degradation in the degradation of TC by Fe0/Ti3C2-MXene. SO4-• and 1O2 play a major role during TC degradation by the radical quenching experiments, XPS and LC-MS. This work not only provides a new strategy for the modification of Ti3C2-MXene with Fe0, but also offers new insights into the efficient degradation of antibiotics in water by Ti3C2-MXene.

Selective fluorescence quenching for volatile benzaldehyde on Zn-based coordination polymers

Benzaldehyde (BZH) is a hazardous substance that can cause respiratory irritation and acute poisoning if it leaks excessively into the environment. Fluorescence detection of BZH is common in liquid phase, but still rare in gas phase. In this study, we synthesized a new complex, [Zn(bpe)(SO4)(H2O)]·2H2O (Zn-bpe), with two-dimensional layered structure. Interestingly, it exhibited good fluorescence quenching behavior not only for BZH dissolved in ethanol, but also for volatile BZH which is detected on thin films prepared by combining complexes with polyvinyl alcohol (Zn-bpe@PVA). Moreover, the limit of detection (LOD = 19.6 mg·L-1) of the latter is firstly calculated through the linear fitting of emission intensities. The quenching mechanism was attributed to the energy transfer from the complex to BZH molecules, which was confirmed by in situ IR spectra and DFT calculations.

Preparation of magnetic carbon nitride composite toward phosphopeptide enrichment

Protein phosphorylation plays an important role in cellular signaling and disease development. Advances in mass spectrometry-based proteomics have enabled qualitative and quantitative phosphorylation studies as well as in-depth biological explorations for biomarker discovery and signaling pathway analysis. However, the dynamic changes that occur during phosphorylation and the low abundance of target analytes render direct analysis difficult because mass spectral detection offers no selectivity, unlike immunoassays such as Western blot and enzyme-linked immunosorbent assay (ELISA). The present study aimed to solve one of the key problems in the specific and efficient isolation of phosphorylated peptides. A method based on a magnetic carbon nitride composite coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed for the enrichment and analysis of phosphopeptides with low abundance in complex samples. Magnetic carbon nitride composite was synthesized and characterized by electron microscopy, infrared spectroscopy, and X-ray diffractometry. The composite showed a well-distributed two-dimensional layered structure and functional groups with excellent paramagnetic performance. Two classical phosphoproteins, namely, α- and β-caseins, were selected as model phosphorylated samples to assess the performance of the proposed enrichment technique. The magnetic carbon nitride composite exhibited high selectivity and sensitivity for phosphopeptide enrichment. The limit of detection was determined by MALDI-TOF-MS analysis to be 0.1 fmol. The selectivity of the method was investigated using the digest mixtures of α-casein, β-casein, and bovine serum albumin (BSA) with different mass ratios (1∶1∶1000, 1∶1∶2000, and 1∶1∶5000). Direct analysis of the samples revealed the dominance of spectral signals from the abundant peptides in BSA. After enrichment with the magnetic carbon nitride composite, the high concentration of background proteins was washed away and only the signals of the phosphopeptides were captured. The signals from the casein proteins were clearly observed with little background noise, indicating the high selectivity of the composite material. The robustness of the method was tested by assessing the reusability of the same batch of magnetic carbon nitride materials over 20 cycles of enrichment. The composite showed nearly the same enrichment ability even after several cycles of reuse, demonstrating its potential applicability for a large number of clinical samples. Finally, the method was applied to the analysis of phosphopeptides from several commonly used phosphoprotein-containing samples, including skimmed milk digest, human serum, and human saliva; these samples are significant in the analysis of food quality, disease biomarkers, and liquid biopsies for cancer. Without enrichment, no phosphopeptide was detected because of the high abundance of nonphosphopeptide materials dominating the spectral signals obtained. After pretreatment with the developed magnetic carbon nitride composite, most of the phosphosites were identified with high selectivity and sensitivity via MALDI-TOF-MS. These results revealed the practicality of the developed approach for clinical applications. In addition, our method may potentially be employed for phosphoproteomics with real complex biological samples.

Insights into cellular interactions of characterized Mg–Al Layered Double Hydroxide on L929 cells

Layered double hydroxides are members of an anionic clay family, characterised by unique two-dimensional layered structures and lend versatility in various applications. These biocompatible compounds have the potential to get intercalated with biological compounds and physico-chemically adsorbed onto organic molecules. Thus, making them important candidates for pharmaceutical and biomedical purposes. This study aims to synthesise, characterise and investigate the cellular toxicity interactions of Mg–Al LDH towards the mouse fibroblast L929 cell line. The Mg–Al LDH was synthesized by a meticulous process of co-precipitation followed by the hydrothermal method to ensure a well-defined and stable structure for suitable biological application. Characterisation techniques like Dynamic Light Scattering, Zeta potential, Scanning Electron Microscopy, Fourier transform infrared, and X-ray diffraction analysis were employed to provide deeper insights into the physiochemical properties and structural integrity of the synthesized Mg–Al LDH. The investigation of cellular interactions with the L929 fibroblast cell line served to assess the biocompatibility and potential cytotoxic effects of Mg–Al LDH. This was observed by assessing the morphological changes and evaluating the cytotoxic effects of Mg–Al LDH by utilising various techniques like phase contrast microscopy, fluorescent staining, and Giemsa staining. The cellular metabolic activity was assessed by MTT assay, and the subcellular lysosomal alteration was examined using the fluorescent staining method by the acridine orange staining. The dose-dependent response observed in the cellular interaction underscores the importance of dosage considerations for potential biomedical applications. By elucidating the dose-response relationship, this study contributes valuable information for the safe and effective usage of LDH in biomedical contexts.

Sustainable CO2-based PPC foams functionalized with enhanced glass transition temperature by a controllable hydrogen bonding complexation

Biodegradable polypropylene carbonate (PPC) has garnered significant attention for its commendable biodegradability and its role in mitigating the greenhouse effect. However, the inherent drawback of PPC, its low glass transition temperature (Tg), severely restricts its widespread use, especially at room temperature. In this study, we explore the utilization of MXene-OH/CNTs-OH (CM) hybrids, which encompass hydroxylated one-dimensional carbon nanotubes (CNTs-OH) and the two-dimensional layered structure of Ti3C2 (MXene-OH), to enhance the properties of PPC through hydrogen bonding complexation. By adjusting the content of nanofillers, the resulting PPC/CM composites demonstrate improved Tg, mechanical strength, and exceptional capability in supercritical foaming. Both experimental and theoretical analyses confirm that the CM crosslinking mechanism significantly elevates the Tg of the composite to 37.3 °C, while also enhancing tensile strength by 23.7% and antibacterial activity by 99.6%. This study presents a straightforward and practical method for developing functionalized, sustainable polymer foams with enhanced characteristics, poised for a diverse range of applications.

Synthesis of graphitic carbon nitride (g-C3N4) by high-temperature condensation for electrochemical evaluation of dichlorophen and thymol in environmental trials

The work deals with synthesizing carbon-based nanomaterial, i.e., graphitic carbon nitride, which was carried out using the high-temperature condensation method. Graphitic carbon nitride is characterized by cost efficiency, increased thermal resilience, a two-dimensional molecular layer structure, biocompatibility and stability. These properties can be used in the electrochemical investigations of fungicides such as dichlorophen and thymol. The synthesized nanomaterial was first characterized using XRD, SEM, UV-DRS, BET, FTIR, CV and EIS investigations. The cyclic voltammetry behavior of dichlorophen and thymol shows the proton-coupled irreversible electron transfer process at a modified carbon paste electrode with the participation of same number of protons and electrons. The developed sensor exhibited good detection limits for the dichlorophen and thymol as low as 15.3 nM and 12.0 nM with the sensitivity of 126.8 µA·µM−1·cm−2 and 59.2 µA·µM−1·cm−2, respectively. The applicability of the developed sensor was tested in spiked soil and water samples, and good recoveries were achieved with a% RSD of 1.67 and 1.30, respectively. The anti-interference responses to metal ions demonstrate the selectivity (qualitative) of the developed sensor in the electrochemical detection of dichlorophen and thymol. In the future, the sensor developed would offer the potential to sensitively and selectively detect other pesticide molecules in environmental samples.

CuGa2 transition phase anchored liquid GaSn achieves high-performance liquid metal battery cathode

Severe volume expansion will cause the gallium-based liquid metal cathode material to detach from the collector thus deteriorating performance. Here, we propose a strategy for preparing electrodes by anchoring the liquid metal with an intermetallic compound transition phase to avoid the problem of liquid metal shedding during cycling. The good reactive wetting between the CuGa2 transition phase and gallium can firmly anchor the liquid metal to prevent the electrode material exfoliating from the collector. On the other hand, the unique two-dimensional layer structure of CuGa2 can also limit the lithiation volume expansion of liquid gallium. Density functional theory (DFT) reveals the anchoring mechanism of the CuGa2 transition layer to liquid gallium and the reaction mechanism of Li with CuGa2 during the electrochemical reaction. As a result, O-GaSn/CF cathodes exhibit low resistance, fast ion diffusion, high reversible capacity, excellent rate performance and outstanding cycling stability.

Synthesis, Structural Characterization, and Hirschfeld Surface Analysis of a New Cu(II) Complex and Its Role in Photocatalytic CO2 Reduction.

A new Cu(II) complex, [CuL1L2(CH3COO)2(H2O)]·H2O, was synthesized by the reaction of Cu(CH3COO)2·H2O, 6-phenylpyridine-2-carboxylic acid (HL1), and 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine (L2) in ethanol-water (v:v = 1:1) solution. The Cu(II) complex was characterized using elemental analysis, IR, UV-vis, TG-DTA, and single-crystal X-ray analysis. The fluorescence properties of the copper complex were also evaluated. The structural analysis results show that the Cu(II) complex crystallizes in the triclinic system with space group P-1. The Cu(II) ion in the complex is five-coordinated with one O atom (O2) and one N atom (N1) from one 6-phenylpyridine-2-carboxylate ligand (L1), one N atom (N2) from 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine ligand (L2), one O atom (O4) from acetate, and one O atom (O5) from a coordinated water molecule, and it adopts a distorted trigonal bipyramidal geometry. Cu(II) complex molecules form a two-dimensional layer structure through intramolecular and intermolecular O-H…O hydrogen bonding. The two-dimensional layer structures further form a three-dimensional network structure by π-π stacking interactions of aromatic rings. The analysis of the Hirschfeld surface of the Cu(II) complex shows that the H…H contacts made the most significant contribution (46.6%) to the Hirschfeld surface, followed by O…H/H…O, N…H/H…N and C…H/H…C contacts with contributions of 14.2%, 13.8%, and 10.2%, respectively. In addition, the photocatalytic CO2 reduction using Cu(II) complex as a catalyst is investigated under UV-vis light irradiation. The findings reveal that the main product is CO, with a yield of 10.34 μmol/g and a selectivity of 89.4% after three hours.

α-Fe2O3/TiO2/Ti3C2Tx Nanocomposites for Enhanced Acetone Gas Sensors.

Metal oxide semi-conductors are widely applied in various fields due to their low cost, easy processing, and good compatibility with microelectronic technology. In this study, ternary α-Fe2O3/TiO2/Ti3C2Tx nanocomposites were prepared via simple hydrothermal and annealing treatments. The composition, morphology, and crystal structure of the samples were studied using XPS, SEM, EDS, XRD, and multiple other testing methods. The gas-sensing measurement results suggest that the response value (34.66) of the F/M-3 sensor is 3.5 times higher than the pure α-Fe2O3 sensor (9.78) around 100 ppm acetone at 220°C, with a rapid response and recovery time (10/7 s). Furthermore, the sensors have an ultra-low detection limit (0.1 ppm acetone), excellent selectivity, and long-term stability. The improved sensitivity of the composites is mainly attributed to their excellent metal conductivity, the unique two-dimensional layered structure of Ti3C2Tx, and the heterojunction formed between the nanocomposite materials. This research paves a new route for the preparation of MXene derivatives and metal oxide nanocomposites.

Tuning Surface Electronics State of P-Doped In2.77S4/In(OH)3 toward Efficient Photoelectrochemical Water Oxidation.

Indium sulfide with a two-dimensional layered structure offers a platform for catalyzing water oxidation by a photoelectrochemical process. However, the limited hole holders hinder the weak intrinsic catalytic activity. Here, the nonmetallic phosphorus atom is coordinated to In2.77S4/In(OH)3 through a bridge-bonded sulfur atom. By substituting the S position by the P dopant, the work function (surface potential) is regulated from 445 to 210 mV, and the lower surface potential is shown to be beneficial for holding the photogenerated holes. In2.77S4/In(OH)3/P introduces a built-in electric field under the difference of Fermi energy, and the direction is from the bulk to the surface. This band structure results in upward band bending at the interface of In2.77S4/In(OH)3 and P-doped sites, which is identified by density functional theory calculations (∼0.8 eV work function difference). In2.77S4/In(OH)3/P stands out with the highest oxidation efficiency (ηoxi = 70%) and charge separation efficiency (ηsep = 69%). Importantly, it delivers a remarkable water oxidation photocurrent density of 2.51 mA cm-2 under one sun of illumination.

Polyimide-assisted fabrication of highly oriented graphene-based all-carbon foams for increasing the thermal conductivity of polymer composites

Graphene and its derivatives are often preferentially oriented horizontally during processing because of their two-dimensional (2D) layer structure. As a result, thermal interface materials (TIMs) composed of a polymer matrix and graphene-derived fillers often have a high in-plane (IP) thermal conductivity (K), however, the low through-plane (TP) K makes them unsuitable for practical use. We report the development of high-quality polyimide/graphite nanosheets (PG) perpendicular to the plane using a directional freezing technique that increase the TP K of polymer-based composites. Graphene-derived nanosheets (GNs) were obtained by the crushing of scraps of highly thermally conductive graphene films. A water-soluble polyamic acid salt solution was used to disperse the hydrophobic GNs filler to achieve directional freezing. The polyimide, which facilitated the directional alignment of the GNs, was then graphitized. The introduction of the GNs increases the order and density of the PG, thus improving the strength and heat transfer performance of its polydimethylsiloxane (PDMS) composite. The obtained PG/PDMS composite (21.1% PG, mass fraction) has an impressive TP K of 14.56 W·m−1·K−1, 81 times that of pure PDMS. This simple polyimide-assisted 2D hydrophobic fillers alignment method provides ideas for the widespread fabrication of anisotropic TIMs and enables the reuse of scraps of graphene films.

Exploring the synthesis, structure, and properties of two 2D transition metal polymers based on 4, 4’-bistriazole 3, 3’-biphenyldicarboxylic acid

Two coordination polymers {[Zn(BTBPA)(H2O)2]·0·5H2O}n (Zn-1), and {[Mn(BTBPA)(H2O)2]·0·5H2O}n (Mn-2) were synthesized solvothermally by the combination of organic linker 4,4′-bistriazole 3,3′-biphenyldicarboxylic acid (H2BTBPA) and Zn(NO3)2·6H2O or MnCl2·4H2O. Both of the polymers 1–2 are as 4,4-linked two-dimensional layered structures, which constitute into three dimensional supramolecular frameworks with porous channels via O − H⋅⋅⋅O hydrogen bonds. Zn-1 exhibits recognition abilities to antibiotics (PCL, NFT and NFZ) with high sensitivity via luminescence “turn-off” mechanism. In addition, the static magnetic performance of Mn-2 was investigated.