Z-机制g-C3N4/Bi/BiOBr异质结光催化剂制备及其可见光降解甲醛气体研究

通过将BiOBr纳米片与g-C₃N₄复合,然后原位还原,合成了具有纳米花状结构的三元异质结光催化剂g-C₃N₄/Bi/BiOBr.对g-C₃N₄/Bi/BiOBr的结构、形貌、元素价态和光学性能等进行了表征和研究.评估了g-C₃N₄/Bi/BiOBr对气体甲醛的光催化降解活性. g-C₃N₄/Bi/BiOBr在可见光照射下降解甲醛的活性与g-C₃N₄、 BiOBr单体和g-C₃N₄/BiOBr二元复合物相比显著提高. 20%-g-C₃N₄/Bi/BiOBr复合物可以在60 min内(λ> 400 nm)降解80%的气态甲醛(初始浓度0.16 mg·L^-1).     

卟啉修饰g-C3N4提高光催化产氢活性研究

半导体光催化制氢是一种可实现持续制备和储存氢气的绿色技术.石墨相氮化碳(g-C3N4)是研究广泛的光催化剂,但其仍存在光利用率低、光生电子和空穴易复合等问题,制约着光催化产氢的性能.利用给电子卟啉修饰g-C3N4,构建了四(4-羧基)苯基卟啉(TCPP)以共价/非共价方式修饰g-C3N4的催化剂.卟啉共价修饰g-C3N4(gC3N4-TCPP0.1)及非共价复合结构(TCPP0.1/g-C3N4)光催化产氢速率分别为6 997和5 399μmol·g-1·h-1,较g-C3N4分别提高了53%和18%. TCPPx/g-C3N4异质结加强了界面接触,促进了电荷转移,增强了可见光吸收能力,进而提高了光催化制氢性能. g-C3N4-TCPPx中, TCPP的接枝拓展了共轭结构,优化了电子结构,增大了分子偶极,促进了电荷分离,共价桥键为电荷传输提供了通道.     

超高效液相色谱-四极杆飞行时间质谱法快速筛查睫毛用化妆品中前列腺素F2α类化合物

采用超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF MS/MS)技术,建立了睫毛用化妆品中9种前列腺素F2α类化合物(比马前列素、曲伏前列素、他氟前列素、他氟乙酰胺、拉坦前列素、比马前列素酸甲基酯、氯前列醇异丙基酯、15-酮-曲伏前列素、比马酰胺)的快速定性筛查方法。样品经乙腈超声提取,采用Waters ACQUITY UPLC BEH C18(2.1 mm×100 mm,1.7μm)色谱柱,以2 mmol/L甲酸铵水溶液(含0.05%甲酸)-乙腈为流动相,分离后进入四极杆飞行时间质谱,采用电喷雾离子源正离子模式(ESI+),以MSE模式进行数据采集,建立了9种前列腺素F2α类化合物的筛查数据库。9种化合物在各自质量浓度范围内线性关系良好,相关系数(r²)均大于0.99,检出限为0.075～0.75μg/g,定量下限为0.25～2.5μg/g。所建立的筛查数据库无需对照品即可对化妆品中的9种前列腺素F2α类化合物进行筛查。结果表明,该方法特异性良好,应用于48批睫毛类化妆品的定性筛查具有良好的选择性,可为化妆品中前列腺素F2α类化合物的筛查分析提供技术支...     

Theoretical Investigation of the Mechanism of Rh(III)-catalyzed Annulation of 2-Biphenylboronic Acid with Activated Alkene

The mechanism is investigated for Cp^tBuRh(OH)₂-catalyzed annulation of 2-biphenylboronic acid with three activated alkenes using M06-2X functional. The reaction comprises transmetalation via two steps and following C-H activation producing reactive Rh-biphenyl complex with two Rh—C σ bonds. After the coordination/insertion of alkenes, respective fused or bridged cyclic products are yielded depending on different alkenes accompanied by the release of Cp^tBuRh. The promotion of Cp^tBuRh(OH)₂ lies in the barrier decrease of transmetalation and C-H activation ready for coordination/insertion ensuring the smooth progress of common rate-limiting reductive elimination. The stereoselective transfer and ring rotation are specific for benzoquinone and cyclopropenone. The role of Rh(III) catalyst and release of Rh(I) is supported by Multiwfn analysis on frontier molecular orbital(FMO) of specific transiton states(TSs) and Mayer bond order(MBO) value of vital bonding, breaking.     

A Gel Polymer Electrolyte with 2D Filler-reinforced for Dendrite Suppression Li-Ion Batteries

Gel polymer electrolytes (GPEs) incorporate both the high ionic conductivity of organic liquid electrolyte and the high safety performance of all-solid-state electrolytes (ASSEs), greatly improving the electrochemical performance of solid polymer electrolytes (SPEs). However, the practical application of GPEs is still limited by inferior interface compatibility, lithium dendrites, etc. Herein, we prepared GPEs based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) further co-blended the two-dimensional sheet inorganic filler hectorite and poly(methyl methacrylate) (PMMA) to improve the mechanical and electrochemical properties of the GPEs. When the content of PMMA and hectorite is optimal, this GPEs have an ionic conductivity of 1.06×10⁻³ S cm⁻¹ and outstanding lithium symmetric cells cycle time of more than 3000 h, indicating that the introduction of filler effectively inhibits the growth of lithium dendrites at room temperature. Moreover, the GPEs adopt a relatively simple solution casting method to provide a fresh idea for the synthesis of high-performance GPEs.     

Electronic Perturbation of Copper Single-Atom CO2 Reduction Catalysts in a Molecular Way

Fine-tuning electronic structures of single-atom catalysts (SACs) plays a crucial role in harnessing their catalytic activities, yet challenges remain at a molecular scale in a controlled fashion. By tailoring the structure of graphdiyne (GDY) with electron-withdrawing/-donating groups, we show herein the electronic perturbation of Cu single-atom CO₂ reduction catalysts in a molecular way. The elaborately introduced functional groups (−F, −H and −OMe) can regulate the valance state of Cu^δ+, which is found to be directly scaled with the selectivity of the electrochemical CO₂-to-CH₄ conversion. An optimum CH₄ Faradaic efficiency of 72.3 % was achieved over the Cu SAC on the F-substituted GDY. In situ spectroscopic studies and theoretical calculations revealed that the positive Cu^δ+ centers adjusted by the electron-withdrawing group decrease the pK_a of adsorbed H₂O, promoting the hydrogenation of intermediates toward the CH₄ production. Our strategy paves the way for precise electronic perturbation of SACs toward efficient electrocatalysis.     

A Humidity-Induced Large Electronic Conductivity Change of 107 on a Metal-Organic Framework for Highly Sensitive Water Detection

The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H₂O on the EC of MOFs is rarely reported. We explored the effect of H₂O on the EC in the MOFs (NH₂)₂-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 10⁷ on H₂SO₄@(NH₂)₂-MIL-125 by H₂O was observed. Brønsted acid–base pairs formed with the −NH₂ groups, and H₂SO₄ played an important role in promoting the charge transfer from H₂O to the MOF. Based on H₂SO₄@(NH₂)₂-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H₂O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials.     

Two-Dimensional Conjugated Metal-Organic Frameworks with Large Pore Apertures and High Surface Areas for NO2 Selective Chemiresistive Sensing

The emergence of two-dimensional conjugated metal–organic frameworks (2D c-MOFs) with pronounced electrical properties (e.g., high conductivity) has provided a novel platform for efficient energy storage, sensing, and electrocatalysis. Nevertheless, the limited availability of suitable ligands restricts the number of available types of 2D c-MOFs, especially those with large pore apertures and high surface areas are rare. Herein, we develop two new 2D c-MOFs (HIOTP-M, M=Ni, Cu) employing a large p-π conjugated ligand of hexaamino-triphenyleno[2,3-b:6,7-b′:10,11-b′′]tris[1,4]benzodioxin (HAOTP). Among the reported 2D c-MOFs, HIOTP-Ni exhibits the largest pore size of 3.3 nm and one of the highest surface areas (up to 1300 m² g⁻¹). As an exemplary application, HIOTP-Ni has been used as a chemiresistive sensing material and displays high selective response (405 %) and a rapid response (1.69 min) towards 10 ppm NO₂ gas. This work demonstrates significant correlation linking the pore aperture of 2D c-MOFs to their sensing performance.     

Nanostructure-Driven Indocyanine Green Dimerization Generates Ultra-Stable Phototheranostics Nanoparticles

Indocyanine green (ICG) is the only near-infrared (NIR) dye approved for clinical use. Despite its versatility in photonic applications and potential for photothermal therapy, its photobleaching hinders its application. Here we discovered a nanostructure of dimeric ICG (Nano-dICG) generated by using ICG to stabilize nanoemulsions, after which ICG enabled complete dimerization on the nanoemulsion shell, followed by J-aggregation of ICG-dimer, resulting in a narrow, red-shifted (780 nm→894 nm) and intense (≈2-fold) absorbance. Compared to ICG, Nano-dICG demonstrated superior photothermal conversion (2-fold higher), significantly reduced photodegradation (−9.6 % vs. −46.3 %), and undiminished photothermal effect (7 vs. 2 cycles) under repeated irradiations, in addition to excellent colloidal and structural stabilities. Following intravenous injection, Nano-dICG enabled real-time tracking of its delivery to mouse tumors within 24 h by photoacoustic imaging at NIR wavelength (890 nm) distinct from the endogenous signal to guide effective photothermal therapy. The unprecedented finding of nanostructure-driven ICG dimerization leads to an ultra-stable phototheranostic platform.