Latest ArticlesNitrogen-doped carbon catalysts with hierarchical porous structure are promising oxygen evolution reaction (OER) catalysts due to the faster mass transfer and better charge carrying ability. Herein, an exquisite high nitrogen-containing ligand was designed and readily synthesized from the low-cost biomolecule adenine. Accordingly, three new MOFs (TJU-103, TJU-104 and TJU-105) were prepared using the Co(Ⅱ) or Mn(Ⅱ) ions as metal nodes. Through rationally controlling pyrolysis condition, in virtue of the high nitrogen content in well-defined periodic structure of the pristine MOFs, TJU-104–900 among the derived MOFs with hierarchical porous structure, i.e., N-doped graphitic carbon encapsulating homogeneously distributed cobalt nanoparticles, could be conveniently obtained. Thanks to the synergistic effect of the hierarchical structure and well dispersed active components (i.e., C=O, Co‒Nx, graphitic C and N, pyridinic N), it could exhibit an overpotential of 280 mV@10 mA/cm2 on carbon cloth for OER activity. This work provides the inspiration for fabrication of nitrogen-doped carbon/metal electrocatalysts from cost-effective and abundant biomolecules, which is promising for practical OER application.
Chiral organic-inorganic metal halide semiconductors (OIMHSs) have recently attracted numerous interests due to their unique chirality, structural tunability, and extensive physical properties. However, most reported chiral OIMHSs contain toxic lead, which will be a potential obstacle to their further applications. Herein, we successfully synthesized a novel chiral lead-free tin(Ⅳ)-based OIMHS [(R)-3-hydroxyquinuclidinium]2SnCl6 ([R-HQ]2SnCl6). It exhibits a wide band gap (Eg) of about 4.11 eV. Moreover, [R-HQ]2SnCl6 undergoes a phase transition around 330 K (Tc) and shows distinct dielectric switching characteristics with good repeatability. This work enriches the chiral lead-free OIMHS family and stimulates further exploration of chiral lead-free OIMHS switching materials
Phase transition and phase separation of formamidinium-cesium (FA-Cs) perovskite during the fabrication and operation processes reduce the efficiency and stability of perovskite solar cells (PSCs). Here, we develop an in situ molecular self-assembly approach on perovskite surface using an amine nickel porphyrin (NiP). The NiP doped perovskite precursor solution was deposited on substrate by blade-coating under ambient condition. NiP molecules self-assemble into supramolecule bound on perovskite surface during the vacuum-assisted process. Such a modification controls the perovskite grain growth to generate the uniform perovskite film. The supramolecule can release the residual lattice strain to inhibit the phase transition of perovskite film, and promote the charge extraction and transport to suppress the phase separation of FA-Cs perovskite during long-term illumination condition. Consequently, the best efficiency of large-area NiP-based FA-Cs-PSCs with the active area of 1.0 cm2 is up to 20.3% (certified as 19.2%), which is close to the record efficiency (20.37%) by blade-coating. Unencapsulated NiP-doped device reveals the remarkably improved overall stabilities. This work affords a novel way to address the phase transition and phase separation in FA-Cs perovskite.
Silicon is recognized as the most advantageous next-generation anode material for LIBs in terms of its extremely high theoretical capacity and appropriate operating voltage. However, the application of Si anode is limited by huge volume expansion emerging with cycling, which in turn induces the collapse of the electrode structure, resulting in rapid capacity decay. Here, we report a strategy using self-swelling artificial laponite to prepare a laponite/MXene/CNT composite framework with both rigidity and flexibility, which can excellently address these challenges of Si anode. The self-swelling artificial laponite participates in the construction of hierarchical and porous structures, providing sufficient buffer space to mitigate the volume expansion of the LixSi alloying reaction. Meanwhile, tough and tightly cross-linked silicate nanosheets can improve the mechanical strength of the framework for strong structural stability. More importantly, the negative charge between the layers of artificial laponite can effectively promote fast Li-ion transport in the electrode. This free-standing silicon anode enables the preparation of high areal capacity electrodes to further enhance the energy density of LIBs and a higher reversible capacity of 2381.8 mAh/g at 0.1 C after 50 cycles with an initial coulombic of 85.6%. This work provides a simple and practical fabrication strategy for developing high-performance Si-based batteries, which can speed up their commercialization.
Food waste (FW) has been recognized as essential reservoir for resource recovery via anaerobic fermentation, which could also bring the potential risk of antibiotic resistance genes (ARGs) dissemination. Although the structural deficiency of FW could be stimulated by enzymatic pretreatment to enhance fermentation efficiency, the influences of enzymatic pretreatment on ARGs fate and microbial metabolic pathways involved in ARGs dissemination have rarely been reported. This work proved that enzymatic pretreatment could effectively decrease the total abundance of ARGs (reduced by 13.8%-24.5%) during long-term FW fermentation. It was found that enzymatic pretreatment significantly reduced the ARGs belonging to the efflux pump, which might be ascribed to its ability to increase membrane permeability. Furthermore, enzymatic pretreatment was in favor of reducing microbial diversity and various potential ARGs host (e.g., Methanosarcina, Clostridium, Prevotella, Parabacteroides). Also, this pretreatment remarkably up-regulated the genetic expressions involved in ABC transporter (e.g., eryF and mntA) and down-regulated the genetic expressions that participated in DNA replication, two-component systems (e.g., uphA and cckA), and quorum sensing (e.g., rpfF and lsrG), thereby decreasing ARGs transmission. This study would expand the insight of the influences of pretreatment method on ARGs fate during FW fermentation, and offer practical guidance on the sustainable management of FW.
Single atom catalysts (SACs) have become the frontier research fields in catalysis. The M1-Nx-Cy based SACs, wherein single metal atoms (M1) are stabilized by N-doped carbonaceous materials, have provided new opportunities for catalysis due to their high reactivity, maximized atomic utilization, and high selectivity. In this review, the fabrication methods of M1-Nx-Cy based SACs via support anchoring strategy and coordination design strategy are summarized to help the readers understand the interaction mechanism of single atoms and support. Then, characterization technologies for identifying single metal atoms are presented. Besides, the environmental applications including management of harmful gases, water purification are discussed. Finally, future opportunities and challenges for preparation strategies, mechanisms and applications are concluded. We conclude this review by emphasizing the fact that M1-Nx-Cy based SACs has the potential to become an important candidate for solving current and future environmental pollution problems.
Small-molecule hydrogels based on amino acid derivatives have promising applications in many biological fields, including cell culture, drug delivery, and tissue engineering. Although these hydrogels have been widely reported to have low cytotoxicity, biocompatibility, and tunable bioactivity, problems such as harsh preparation conditions and complex material design hinder their application. Herein, by adjusting pH to induce non-covalent interactions between small-molecule tryptophan derivatives (N-[(phenylmethoxy)carbonyl]-L-tryptophan, Mw: 338.35), we developed a self-assembled three-dimensional network hydrogel that can be rapidly formed in seconds. And the supramolecular self-assembly mechanism of the hydrogels was also investigated in detail through experimental characterizations and density functional theory calculation. As-prepared hydrogels also exhibit reversible pH-stimulated response and self-healing properties. This study details a research process for the simple and rapid preparation of tryptophan derivative-based hydrogels, which provides more reference ideas for the future development of materials based on other amino acid derivatives.
Among the emitters in powder dusting to visualize the latent fingerprints (LFPs), aggregation-induced emission luminogens (AIEgens) are well employed for their high brightness and resistance to photo-bleaching. However, the serious background interference and low resolution still limit their fast development. Therefore, to further enhance the signal-to-noise ratio in LFPs imaging, especially to improve the analysis for level 3 details, donor-acceptor (D-A) typed AIEgens of DTPA-2,3-P, DTPA-2,5-P and DTPA-2,6-P are designed here. It is observed that strong emission covering from 450 nm to 650 nm can be obtained for all these molecules, especially that a high PLQY value of 10.06% in solids is achieved in DTPA-2,3-P. This is much higher than that of the other two cases (0.80% and 0.51%). By utilizing the DTPA-2,3-P in powder dusting, fluorescence imaging of LFPs can be clearly captured on both smooth and rough substrates. Moreover, confocal laser scanning microscope (CLSM) enables us to achieve high-resolution LFPs imaging in both 2D and 3D views, providing more detailed information of fingerprints pores in width, distance, distribution, and shapes. The results here demonstrate that highly emissive AIEgen of DTPA-2,3-P could be an excellent candidate for the visualization of fingerprints, thus providing the potential application in criminal investigation in the future.
Aqueous zinc ion batteries (AZIBs) have attracted much attention in recent years due to their high safety, low cost, and decent electrochemical performance. However, the traditional electrodes development process requires tedious synthesis and testing procedures, which reduces the efficiency of developing high-performance battery devices. Here, we proposed a high-throughput screening strategy based on first-principles calculations to aid the experimental development of high-performance spinel cathode materials for AZIBs. We obtained 14 spinel materials from 12,047 Mn/Zn-O based materials by examining their structures and whether they satisfy the basic properties of electrodes. Then their band structures and density of states, open circuit voltage and volume expansion rate, ionic diffusion coefficient and energy barrier were further evaluated by first-principles calculations, resulting in five potential candidates. One of the promising candidates identified, Mg2MnO4, was experimentally synthesized, characterized and integrated into an AZIB based cell to verify its performance as a cathode. The Mg2MnO4 cathode exhibits excellent cycling stability, which is consistent with the theoretically predicted low volume expansion. Moreover, at high current density, the Mg2MnO4 cathode still exhibits high reversible capacity and excellent rate performance, indicating that it is an excellent cathode material for AZIBs. Our work provides a new approach to accelerate the development of high-performance cathodes for AZIBs and other ion batteries.
The key building blocks, tetrachlorinated terrylene diimides and the targeted sila-annulated terrylene diimides (Si-TDIs and 2Si-TDIs) were synthesized for the first time. Single-crystal analysis verified the almost planar molecular configurations of both Si-TDIs and 2Si-TDIs. They exhibited intriguing optical properties including red-shifted absorption and near-infrared emission properties with excellent fluorescence quantum yields, as well as precisely controlled HOMO/LUMO energy levels by Si-heteroannulation. The single-crystal organic field-effect transistors based on 2Si-TDI 5a featuring long and branched alkyl chains demonstrated well-balanced ambipolar transporting properties with electron/hole mobilities of 0.10/0.18 cm2 V−1 s−1.
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