木质素系和萘系分散剂在煤水界面的吸附性能

研究了两种木质素类分散剂SL(木质素磺酸钠)和MSSL(改性磺化碱木质素钠盐)和一种萘系分散剂(FDN)在大同煤表面的吸附量和动力学, 结果表明, SL和MSSL在煤表面的吸附量远比FDN的大, 但是拟合所得的Langmuir平衡常数K和吸附速率常数ka都比FDN的小, 这表明SL和MSSL在煤表面的吸附能力比FDN略差, 吸附速率较慢. 采用IR和XPS研究了煤表面分散剂吸附层的结果表明, 吸附了SL和MSSL的煤表面具有明显的“红移”现象, 并且SL和MSSL在煤表面的吸附层厚度分别为7.22和4.61 nm, 而FDN的吸附层厚度较小, 为2.11 nm. 分析认为, SL和MSSL在煤表面的吸附以氢键力为主, 吸附量较大, 吸附层较厚, 在煤表面呈多点式吸附; FDN主要以π电子极化吸附在煤表面呈卧式吸附, 吸附强度较大, 吸附层较薄.     

3D Tungsten Trioxide Nanosheets as Optoelectronic Materials for On-chip Quantification of Global Antioxidant Capacity

The photoelectrochemical properties of semiconductors mainly depend on the size and shape of the corresponding nanoparticles. Herein, 3D WO₃ nanosheets were controllably synthesized with the aid of polyethyleneimine, which presents enhanced photocurrent responses. Based on this excellent photoelectrochemical property, a photoelectrochemical chip was prepared by lithography technology for the smart monitoring of the antioxidant capacity(AC) in red wine and exhibits a series of advantages inclu-ding rapid response time, high sensitivity, and long-lasting stability. The mechanism of the present photoelectrochemical sensing was explored and shows a single electron transfer reaction. Furthermore, only 200 μL of samples are required for one testing, which demonstrates that the present photoelectrochemical chip can be potentially integrated with a portable commercial device(such as a mobile phone) for further research and development of food and drug supervision.     

Dimensional Reduction of Metal–Organic Frameworks for Enhanced Cryopreservation of Red Blood Cells

To increase the red blood cell (RBC) cryopreservation efficiency by metal–organic frameworks (MOFs), a dimensional reduction approach has been proposed. Namely, 3D MOF nanoparticles are progressively reduced to 2D ultra-thin metal–organic layers (MOLs). We found that 2D MOLs are beneficial for enhanced interactions of the interfacial hydrogen-bonded water network and increased utilization of inner ordered structures, due to the higher surface-to-volume ratio. Specifically, a series of hafnium (Hf)-based 2D MOLs with different thicknesses (monolayer to stacked multilayers) and densities of hydrogen bonding sites have been synthesized. Both ice recrystallization inhibition activity (IRI) and RBCs cryopreservation assay confirm the pronounced better IRI activity and excellent cell recovery efficiency (up to ≈63 % at a very low concentration of 0.7 mg mL⁻¹) of thin-layered Hf-MOLs compared to their 3D counterparts, thereby verifying the dimensional reduction strategy to improved cryoprotectant behaviors.     

Type-II Red Phosphorus: Wavy Packing of Twisted Pentagonal Tubes

Elemental phosphorus exhibits fascinating structural varieties and versatile properties. The unique nature of phosphorus bonds can lead to the formation of extremely complex structures, and detailed structural information on some phosphorus polymorphs is yet to be investigated. In this study, we investigated an unidentified crystalline phase of phosphorus, type-II red phosphorus (RP), by combining state-of-the-art structural characterization techniques. Electron diffraction tomography, atomic-resolution scanning transmission electron microscopy (STEM), powder X-ray diffraction, and Raman spectroscopy were concurrently used to elucidate the hidden structural motifs and their packing in type-II RP. Electron diffraction tomography, performed using individual crystalline nanowires, was used to identify a triclinic unit cell with volume of 5330 ų, which is the largest unit cell for elemental phosphorus crystals up to now and contains approximately 250 phosphorus atoms. Atomic-resolution STEM imaging, which was performed along different crystal-zone axes, confirmed that the twisted wavy tubular motif is the basic building block of type-II RP. Our study discovered and presented a new variation of building blocks in phosphorus, and it provides insights to clarify the complexities observed in phosphorus as well as other relevant systems.     

Red Emissive Double Aza[7]helicenes with Antiaromaticity / Aromaticity Switching via the Redox-Induced Radical Cation and Dication Species

We herein present the synthetic approach to a new antiaromatic double aza[7]helicene C that features NN-embedded polycyclic aromatic hydrocarbons (PAHs). This heteroatom-doped helicene showed a rarely obtained long-wavelength emission and far-red circularly polarized luminescence (CPL) in the solid state. These optical and chiroptical properties could be ascribed to both the NN-PAH core structure and the further extension through angular ring fusions. Such a unique electronic structure also culminated in facile chemical oxidations of neutral C to the positively charged chiral radical ( C ⋅⁺) and dication species ( C ²⁺). Interestingly, DFT computations revealed that the pyridazine central core showed an antiaromaticity-to-aromaticity switching, in contrast to the inversed transition for the helical periphery in cationic states. The reported approaches are anticipated to lead to the development of further redox-active chiral systems for potential applications in chiroptoelectronics, spintronics as well as fluorescent bioimaging.     

Hyperbranched Polyborosiloxanes: Non-traditional Luminescent Polymers with Red Delayed Fluorescence

Non-traditional fluorescent polymers have attracted significant attention for their excellent biocompatibility and diverse applications. However, designing and preparing non-traditional fluorescent polymers that simultaneously possess long emission wavelengths and long fluorescence lifetime remains challenging. In this study, a series of novel hyperbranched polyborosiloxanes (P1–P4) were synthesized. As the electron density increases on the monomer diol, the optimal emission wavelengths of the P1–P4 polymers gradually red-shift to 510, 570, 575, and 640 nm, respectively. In particular, P4 not only exhibits red emission but also demonstrates delayed fluorescence with a lifetime of 9.73 μs and the lowest critical cluster concentration (1.76 mg/mL). The experimental results and theoretical calculations revealed that the synergistic effect of dual heteroatom-induced electron delocalization and through-space O⋅⋅⋅O and O⋅⋅⋅N interaction was the key factor contributing to the red-light emission with delayed fluorescence. Additionally, these polymers showed excellent potential in dual-information encryption. This study provides a universal design strategy for the development of unconventional fluorescent polymers with both delayed fluorescence and long-wavelength emission.     

Mimicking Photosynthesis: A Natural Z-Scheme Photocatalyst Constructed from Red Mud Bauxite Waste for Overall Water Splitting

All-solid-state Z-Scheme photocatalysts have attracted significant attention due to their great potential for solar fuel production. However, delicately coupling two individual semiconductors with a charge shuttle by a material strategy remains a challenge. Herein, we demonstrate a new protocol of natural Z-Scheme heterostructures by strategically engineering the component and interfacial structure of red mud bauxite waste. Advanced characterizations elucidated that the hydrogen-induced formation of metallic Fe enabled the effective Z-Scheme electron transfer from γ-Fe₂O₃ to TiO₂, leading to the significantly boosted spatial separation of photo-generated carriers for overall water splitting. To the best of our knowledge, it is the first Z-Scheme heterojunction based on natural minerals for solar fuel production. Thus our work provides a new avenue toward the utilization of natural minerals for advanced catalysis applications.     

Optical grating recording in highly organized thin films of Disperse Red 1

Optical grating recording with submicrometer spatial resolution, which can handle grey-level patterns, has been investigated in photochromic material made of Disperse Red 1 (DR1) molecules vacuum-deposited on a glass substrate. Holographic gratings of periods Λ within the range of 0.6 μm - 12 μm were recorded by 514.5 nm light from cw Ar⁺ laser using a degenerate two-wave mixing technique. Despite the very small DR1 layer thickness (∼ 0.1 μm), the diffraction efficiency measured in a Raman-Nath scattering regime reached 2 %. The obtained amplitude gratings were analysed with an optical microscope and Fourier transforms. Grating profiles were analysed in relation to exposure conditions and in correlation with molecular organisation. Polarising microscopy studies revealed the presence of light-induced optical anisotropy. Following that, we have checked the possibility of polarisation-sensitive recording in this medium.