多功能Fe3O4@SiO2 Janus颗粒

采用溶剂热法和溶胶-凝胶法制备了顺磁性Fe₃O₄@SiO₂颗粒,以Pickering乳液界面保护法实现颗粒表面分区获得Fe₃O₄@SiO₂ Janus颗粒,进一步选区复合生长Pt或Ag纳米颗粒制备Fe₃O₄@SiO₂-Pt和Fe₃O₄@SiO₂-Ag Janus颗粒.Fe₃O₄@SiO₂-Pt Janus颗粒的Pt一侧进行催化过氧化氢的反应,具有自驱动功能.因其顺磁性和两亲性,Fe₃O₄@SiO₂-Ag Janus颗粒能够作为磁响应颗粒乳化剂稳定油水乳液,并将Ag的催化功能引入界面.     

Methanol synthesis from CO2: a DFT investigation on Zn-promoted Cu catalyst

Research on Chemical Intermediates - The reaction steps during methanol synthesis from CO2/H2 are influenced by the type of catalysts such as pure Cu and Zn-decorated Cu. In this study, density...     

Strong and Superhydrophobic Wood with Aligned Cellulose Nanofibers as a Waterproof Structural Material†

Lightweight structural materials are important for the energy efficiency of applications, particularly those in the building sector. Here, inspired by nature, we developed a strong, superhydrophobic, yet lightweight material by simple in situ growth of nano‐SiO₂ and subsequent densification of the wood substrate. In situ generation of SiO₂ nanoparticles both inside the wood channels and on the wood surfaces gives the material superhydrophobicity, with static and dynamic contact angles of 159.4^o and 3^o, respectively. Densification of the wood to remove most of the spaces among the lumen and cell walls results in a laminated, dense structure, with aligned cellulose nanofibers, which in turn contributes to a high mechanical strength up to 384.2 MPa (7‐times higher than natural wood). Such treatment enables the strong and superhydrophobic wood (SH‐Wood) to be stable and have excellent water, acid, and alkaline resistance. The high mechanical strength of SH‐Wood combined with its excellent structural stability in harsh environments, as well its low density, positions the strong and superhydrophobic wood as a promising candidate for strong, lightweight, and durable structural materials that could potentially replace steel.     

Remote regioselective organocatalytic asymmetric [3+2] cycloaddition of N-2,2,2-trifluoroethyl isatin ketimines with cyclic 2,4-dienones

An organocatalytic asymmetric [3+2] cycloaddition of trifluoromethyl-containing azomethine ylides with cyclic 2,4-dienones was developed.The process enables efficient incorporation of CF3 groups into functionalized spiro [pyrro lid in-3,2'-oxindoles] in high yields with good to excellent enantio-and diastereoselectivities.     

有机电极材料固定化策略

有机电极材料因其理论比容量高、低成本、环境友好以及分子结构可设计性强等特点,有望成为下一代可持续和多功能能量储存设备的有效电极材料。然而,根据“相似相溶”原理,该类材料极易溶解在有机电解液中,导致电池容量衰减快、循环稳定性和倍率性能也较差。目前已有许多研究致力于通过“固定化”过程解决有机电极材料的溶解问题。本综述针对有机电极材料的固定化策略展开评述,介绍了有机电极材料的固定化机理,以及各种固定化策略在不同种类有机电极材料中所起的作用,指出了有机电极材料面临的挑战,并对未来的研究和改进方向进行展望。     

Recent Advance of Tellurium for Biomedical Applications

Tellurium(Te) nanomaterials have aroused a wide interest in semiconductor, thermoelectric, piezoelectric, as well as biomedical applications. The last decades of reports indicated a major nanostructure of one-dimensional (1D) Te on account of its inherent structural anisotropy. Two-dimenional(2D) Te has been newly developed and drawn a lot of interests recently. This review presents the intrinsic biological potential of Te-based nanomaterials and summarizes their up-to-date advance in phototherapy and reactive oxygen species(ROS)-related applications in the biomedical field.     

Defect-induced anisotropic surface reactivity and ion transfer processes of anatase nanoparticles

Surface reactivity and ion transfer processes of anatase TiO₂ nanocrystals were studied using lithium bis(trifluoromethylsulfone)imide (LiTFSI) as a probing molecule. Analysis of synthesized anatase TiO₂ by electron microscopy reveals aggregated nanoparticles (average size ~8 nm) with significant defects (holes and cracks). With the introduction of LiTFSI salt, the Li⁺-adsorption propensity towards the surface along the anatase (100) step edge plane is evident in both x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analysis. Ab initio molecular dynamics (AIMD) analysis corroborates the site-preferential interaction of Li⁺ cations with oxygen vacancies and the thermodynamically favorable transport through the (100) step edge plane. Using ⁷Li nuclear magnetic resonance (NMR) chemical shift and relaxometry measurements, the presence of Li⁺ cations near the interface between TiO₂ and the bulk LiTFSI phase was identified, and subsequent diffusion properties were analyzed. The lower activation energy derived from NMR analysis reveals enhanced mobility of Li⁺ cations along the surface, in good agreement with AIMD calculations. On the other hand, the TFSI^– anion interaction with defect sites leads to CF₃ bond dissociation and subsequent generation of carbonyl fluoride-type species. The multimodal spectroscopic analysis including NMR, electron paramagnetic resonance (EPR), and x-ray photoelectron spectroscopy (XPS) confirms the decomposition of TFSI^– anions near the anatase surface. The reaction mechanism and electronic structure of interfacial constituents were simulated using AIMD calculations. Overall, this work demonstrates the role of defects at the anatase nanoparticle surface on charge transfer and interfacial reaction processes.     

Alloyed Crystalline CdSe1-xSx Semiconductive Nanomaterials – A Solid State 113Cd NMR Study

Solid-state NMR analysis on wurtzite alloyed CdSe_1−xS_x crystalline nanoparticles and nanobelts provides evidence that the ¹¹³Cd NMR chemical shift is not affected by the varying sizes of nanoparticles, but is sensitive to the S/Se anion molar ratios. A linear correlation is observed between ¹¹³Cd NMR chemical shifts and the sulfur component for the alloyed CdSe_1−xS_x (0<x<1) system both in nanoparticles and nanobelts (δ_Cd=169.71⋅X_S+529.21). Based on this correlation, a rapid and applied approach has been developed to determine the composition of the alloyed nanoscalar materials utilizing ¹¹³Cd NMR spectroscopy. The observed results from this system confirm that one can use ¹¹³Cd NMR spectroscopy not only to determine the composition but also the phase separation of nanomaterial semiconductors without destruction of the sample structures. In addition, some observed correlations are discussed in detail.     

Direct Imaging of Atomically Dispersed Molybdenum that Enables Location of Aluminum in the Framework of Zeolite ZSM‐5

Integrated differential phase‐contrast scanning transmission electron microscopy (iDPC‐STEM) is capable of directly probing guest molecules in zeolites, owing to its sufficient and interpretable image contrast for both heavy and light elements under low‐dose conditions. This unique ability is demonstrated by imaging volatile organic compounds adsorbed in zeolite Silicalite‐1; iDPC‐STEM was then used to investigate molybdenum supported on various zeolites including Silicalite‐1, ZSM‐5, and mordenite. Isolated single‐Mo clusters were observed in the micropores of ZSM‐5, demonstrating the crucial role of framework Al in driving Mo atomically dispersed into the micropores. Importantly, the specific one‐to‐one Mo‐Al interaction makes it possible to locate Al atoms, that is, catalytic active sites, in the ZSM‐5 framework from the images, according to the positions of Mo atoms in the micropores.     

Designing Sub‐2 nm Organosilica Nanohybrids for Far‐Field Super‐Resolution Imaging

Stimulated emission depletion (STED) microscopy enables ultrastructural imaging of biological samples with high spatiotemporal resolution. STED nanoprobes based on fluorescent organosilica nanohybrids featuring sub‐2 nm size and near‐unity quantum yield are presented. The spin–orbit coupling (SOC) of heavy‐atom‐rich organic fluorophores is mitigated through a silane‐molecule‐mediated condensation/dehalogenation process, resulting in bright fluorescent organosilica nanohybrids with multiple emitters in one hybrid nanodot. When harnessed as STED nanoprobes, these fluorescent nanohybrids show intense photoluminescence, high biocompatibility, and long‐term photostability. Taking advantage of the low‐power excitation (0.5 μW), prolonged singlet‐state lifetime, and negligible depletion‐induced re‐excitation, these STED nanohybrids present high depletion efficiency (>96 %), extremely low saturation intensity (0.54 mW, ca. 0.188 MW cm^?2), and ultra‐high lateral resolution (ca. λ_em/28).