Steric Mixed-Cation 2D Perovskite as a Methylammonium Locker to Stabilize MAPbI3

The reduced dimension perovskite including 2D perovskites are one of the most promising strategies to stabilize lead halide perovskite. A mixed-cation 2D perovskite based on a steric phenyltrimethylammonium (PTA) cation is presented. The PTA-MA mixed-cation 2D perovskite of PTAMAPbI₄ can be formed on the surface of MAPbI₃ (PTAI-MAPbI₃) by controllable PTAI intercalation by either spin coating or soaking. The PTAMAPbI₄ capping layer can not only passivate PTAI-MAPbI₃ perovskite but also act as MA⁺ locker to inhibit MAI extraction and significantly enhance the stability. The highly stable PTAI-MAPbI₃ based perovskite solar cells exhibit a reproducible photovoltaic performance with a champion PCE of 21.16 %. Such unencapsulated devices retain 93 % of initial efficiency after 500 h continuous illumination. This steric mixed-cation 2D perovskite as MA⁺ locker to stabilize the MAPbI₃ is a promising strategy to design stable and high-performance hybrid lead halide perovskites.     

Surface-Polarity-Induced Spatial Charge Separation Boosts Photocatalytic Overall Water Splitting on GaN Nanorod Arrays

Photocatalytic overall water splitting has been recognized as a promising approach to convert solar energy into hydrogen. However, most of the photocatalysts suffer from low efficiencies mainly because of poor charge separation. Herein, taking a model semiconductor gallium nitride (GaN) as an example, we uncovered that photogenerated electrons and holes can be spatially separated to the nonpolar and polar surfaces of GaN nanorod arrays, which is presumably ascribed to the different surface band bending induced by the surface polarity. The photogenerated charge separation efficiency of GaN can be enhanced significantly from about 8 % to more than 80 % via co-exposing polar and nonpolar surfaces. Furthermore, spatially assembling reduction and oxidation cocatalysts on the nonpolar and polar surfaces remarkably boosts photocatalytic overall water splitting, with the quantum efficiency increased from 0.9 % for the film photocatalyst to 6.9 % for the nanorod arrays photocatalyst.     

Switchable Polymerization Triggered by Fast and Quantitative Insertion of Carbon Monoxide into Cobalt–Oxygen Bonds

A strategy that uses carbon monoxide (CO) as a molecular trigger to switch the polymerization mechanism of a cobalt Salen complex [salen=(R,R)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine] from ring-opening copolymerization (ROCOP) of epoxides/anhydrides to organometallic mediated controlled radical polymerization (OMRP) of acrylates is described. The key phenomenon is a rapid and quantitative insertion of CO into the Co−O bond, allowing for in situ transformation of the ROCOP active species (Salen)Co^III-OR into the OMRP photoinitiator (Salen)Co^III-CO₂R. The proposed mechanism, which involves CO coordination to (Salen)Co^III-OR and subsequent intramolecular rearrangement via migratory insertion has been rationalized by DFT calculations. Regulated by both CO and visible light, on-demand sequence control can be achieved for the one-pot synthesis of polyester-b-polyacrylate diblock copolymers (Đ<1.15).     

Amidation-Dominated Re-Assembly Strategy for Single-Atom Design/Nano-Engineering: Constructing Ni/S/C Nanotubes with Fast and Stable K-Storage

An amidation-dominated re-assembly strategy is developed to prepare uniform single atom Ni/S/C nanotubes. In this re-assembly process, a single-atom design and nano-structured engineering are realized simultaneously. Both the NiO₅ single-atom active centers and nanotube framework endow the Ni/S/C ternary composite with accelerated reaction kinetics for potassium-ion storage. Theoretical calculations and electrochemical studies prove that the atomically dispersed Ni could enhance the convention kinetics and decrease the decomposition energy barrier of the chemically-absorbed small-molecule sulfur in Ni/S/C nanotubes, thus lowering the electrode reaction overpotential and resistance remarkably. The mechanically stable nanotube framework could well accommodate the volume variation during potassiation/depotassiation process. As a result, a high K-storage capacity of 608 mAh g⁻¹ at 100 mA g⁻¹ and stable cycling capacity of 330.6 mAh g⁻¹ at 1000 mA g⁻¹ after 500 cycles are achieved.     

一种新型有机质子响应荧光分子的合成在实验教学中的设计与探索

本实验将最新的科研热点——有机发光材料引入实验教学,开发了基于一个荧光分子二甲氨基苯乙烯基苯并噁唑的合成实验,并考查了其质子响应性质。本实验反应温和易控,操作简单,现象明显,绿色环保,并且可以用于模块化教学,拆分成多个环节实验,适合不同学时的实验教学要求,既可培养学生的基本操作,又能激发学生的实验兴趣,锻炼学生的综合能力。     

3D打印便携式凝胶电泳装置用于蛋白质的快速检测

随着现场分析对于快速、便携和经济型检测的需求,分析仪器的便携化和微型化备受关注。3D打印技术的不断发展,将会极大推动小型化、便携式实验设备的开发和研制。分析仪器的微型化有助于促进资源不足地区在医疗现场、食品安全和环境污染等方面的现场监测。目前,用于蛋白质分离的凝胶电泳装置多为实验室用小型化分析仪器,可用于现场快速分离蛋白质的小型化仪器尚未见报道。该研究设计加工了一款便携式凝胶电泳装置,用于蛋白质的快速分离检测。首先,通过3D打印加工的凝胶电泳装置可在实验室内方便、快捷、低成本的复制。其次,通过对预染蛋白质相对分子质量标准的分离测试,对该系统结构进行优化。优化后该凝胶电泳装置电泳槽的尺寸仅为15 mm×20 mm×17 mm,采用3D打印技术可在5 h内加工完成,耗费打印材料10 mL。正负极所用电泳缓冲液共需4 mL,所使用的25 V锂电池可实现100 h左右的工作时间。装置优化后可实现蛋白质的快速高效分离。随后,在5种常用蛋白质相对分子质量标准的分离中,该装置与商业化平板凝胶电泳分离效果相当,同时具备更快的分离速度。该研究在便携式凝胶电泳装置的开发及其在蛋白质快速分离方面取得了初步成果,但在分离完成后立即对蛋白质进行定量分析以及更多实际样品的应用方面还需要进一步研究。     

UTSA-280的氨改性以及C2H4/C2H6分离性能研究

炼厂干气中回收乙烯是扩宽C₂H₄来源的有效途径,但C₂H₄和C₂H₆物理性质和分子尺寸非常接近,分离困难.金属有机骨架材料（MOFs）近年来在低碳烃分离领域展现出广阔的前景.本工作采用氨吸附改性调节UTSA-280的结构,通过一维直孔道大小的调节实现C₂H₄/C₂H₆的高效分离.改性后的UTSA-280具有独特的超微孔结构能提升C₂H₄的吸附,而完全不吸附稍大的C₂H₆,实现理想的C₂H₄/C₂H₆吸附选择性（>1000）.结果表明,改性后的UTSA-280的C₂H₄吸附量可提高至2.83 mmol/g,与未改性的材料相比增加29%,并且能阻挡C₂H₆的吸附,最终达到>1200的C₂H₄/C₂H₆选择性.蒙特卡罗分子模拟（GCMC）计算C₂H₄/C₂H₆混合气体（1：1）的吸附得出,改性后UTSA-280孔内的C₂H₄吸附相比于C₂H₆具有更多的吸附分布.通过C₂H₄/C₂H₆混合气体穿透实验测试,改性后的UTSA-280材料能展现出48 min以上的分离时间,相比于未改性的材料,分离性能提升近1倍.     

N-杂环卡宾配体在聚合反应中的研究进展

N-杂环卡宾配体的优异催化性能引起了人们的广泛关注, 已成功应用于多种烯烃聚合反应。本文结合N-杂环卡宾的相关研究报道,首先简要介绍N-杂环卡宾,随后重点介绍N-杂环卡宾在开环易位聚合、烯烃配位聚合和原子转移自由基聚合等聚合反应的应用。在此基础上,指出了今后N-杂环卡宾配体在聚合反应研究的发展方向。     

食品中7种常见的非食用色素检测研究进展

食用色素可以明显的改善食品外观,激发食欲,在食品行业有着广泛的应用,但一些不法分子为了牟取暴利向食品中添加非食用色素来代替食用色素,但是非食用色素对人体存在致癌风险。食品中常见的非食用色素有以下7种：碱性嫩黄O、碱性橙II、酸性橙II、苏丹红、罗丹明B、美术绿和孔雀石绿,而目前对这7种非食用色素的检测还未全部建立国家标准。本文综述了近3年来食品行业中针对这7种非食用色素的各种检验方法,以期为食品安全监督监督检测机构提供参考。     

基于环糊精构筑的镧系稀土发光超分子组装体

镧系元素由于其优异的发光特性,如长寿命的激发态、尖锐的线状发射带和较大的Stokes位移等,在发光材料中表现出极大的优势,被越来越多地应用于高级功能发光材料的设计中.而环糊精作为第二代超分子主体分子具有易于功能化修饰以及特异性结合发光客体等优势而被广泛地用于构筑发光材料、荧光传感等超分子体系.作者从基于环糊精的镧系稀土配位化合物超分子组装体的构筑出发,对不同镧系环糊精发光材料的最新研究进展进行综述,为开发构筑新型多功能化镧系发光材料提供参考.最后,提出了稀土发光材料目前所遇到的科学问题,并对基于环糊精稀土发光材料的发展方向进行了展望.