Nanjing University

About: Nanjing University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 85961 authors who have published 105504 publications receiving 2289036 citations. The organization is also known as: NJU & Nanking University.

The recent achievements of redox-neutral radical C–C cross-coupling enabled by visible-light

Abstract: Visible-light photoredox catalysis has been esteemed as one sustainable and attractive synthetic tool. In the past four years, a new yet challenging trend, visible-light-driven redox-neutral radical C–C cross-coupling involving putative radical intermediates, has been booming rapidly. Its advent brings a powerful platform to achieve non-classical C–C connections, and should lead to fundamental changes in retrosynthetic analysis. In this tutorial review, we highlight the recent achievements of visible-light-mediated redox-neutral radical C(sp3)–C(sp2), C(sp3)–C(sp), and C(sp3)–C(sp3) bond formation, opening a new window for C–C cross-coupling through the photoredox electron shuttling cycle between two coupling partners. While radical–radical coupling steered by the persistent radical effect was proposed as a rational explanation for the redox-neutral photoredox events, alternative kinetically driven chain propagation and radical addition pathways cannot be ruled out. This tutorial review aims to highlight the recent achievements of photoredox-neutral radical C–C coupling in synthetic chemistry.

Adsorption of hydroxyl- and amino-substituted aromatics to carbon nanotubes.

Abstract: The combined effects of hydroxyl/amino functional groups of aromatics and surface O-containing groups of carbon nanotubes on adsorption were evaluated. When normalized for hydrophobicity, 2,4-dichlorophenol and 2-naphthol exhibited a greater adsorptive affinity to carbon nanotubes and graphite (a model adsorbent without the surface O functionality) than structurally similar 1,3-dichlorobenzene and naphthalene, respectively, and 1-naphthylamine exhibited a much greater adsorptive affinity than all other compounds. Results of the pH-dependency experiments further indicated that the hydroxyl/amino functional groups of the adsorbates and the surface properties of the adsorbents played a combinational role in determining the significance of the nonhydrophobic adsorptive interactions. We propose that the strong adsorptive interaction between hydroxyl-substituted aromatics and carbon nanotubes/graphite was mainly due to the electron-donating effect of the hydroxyl group, which caused a strong electron-donor−acce...

Co3O4@graphene Composites as Anode Materials for High-Performance Lithium Ion Batteries

Abstract: This paper reports on the synthesis of Co3O4@graphene composites (CGC) and their applications as anode materials in lithium ion batteries (LIBs). Through a chemical deposition method, Co3O4 nanoparticles (NPs) with sizes in the range of 10−30 nm were homogeneously dispersed onto graphene sheets. Due to their high electrical conductivity, the graphene sheets in the CGC improved the electrical conductivity and the structure stability of CGC. CGC displayed a superior performance in LIBs with a large reversible capacity value of 941 mA hg−1 in the initial cycle with a large current density and an excellent cyclic performance of 740 mA hg−1 after 60 cycles, corresponding to 88.3% of the theoretical value of CGC, owing to the interactions between graphene sheets and Co3O4 NPs anchored on the graphene sheets. This synthesis approach may find its application in the design and synthesis of novel electrode materials used in LIBs.

Recent advances in titanium-based electrode materials for stationary sodium-ion batteries

Abstract: Recently, the attention to sodium-ion batteries has been refocused on large-scale energy storage applications, due to sodium's low cost and infinite abundance. Sodium is one of the most abundant elements on earth and exhibits chemical properties similar to lithium. Owing to their superior sodium storage capability especially for excellent safety and stability, Ti-based compounds have been extensively investigated as both cathode and anode materials. Herein we outline the current cathodes and anodes, and emphasize the critical roles of titanium in developing advanced electrodes for sodium-ion batteries. The latest advances and progress in the exploration of Ti-based compounds with various different frameworks such as NASICON, tunnel, MXenes, spinel, and layered structures are systematically reviewed. The straightforward linking of the structure–function–property relationship for Ti-based compounds, especially for layered Na/Ti-containing oxides, is summarized and analyzed. The titanium element plays a critical role in both positive and negative electrodes, i.e., supplying the charge transfer and high safety for anodes and greatly enhancing the structural and cycling stability for cathodes. Based on the bi-functional roles of titanium, a new concept of symmetric Na-ion cells employing layered Na/Ti-containing oxides as bipolar electrodes is proposed and realized. Symmetric Na-ion cells already offered a high voltage and withstood long time charge–discharge processes, demonstrating the practicality beyond the proof of concept. The participation of titanium in sodium-based electrode materials will greatly promote the development of room-temperature sodium-ion batteries towards stationary energy storage.

Van der Waals epitaxial growth and optoelectronics of large-scale WSe 2 /SnS 2 vertical bilayer p–n junctions

Abstract: High-quality two-dimensional atomic layered p–n heterostructures are essential for high-performance integrated optoelectronics. The studies to date have been largely limited to exfoliated and restacked flakes, and the controlled growth of such heterostructures remains a significant challenge. Here we report the direct van der Waals epitaxial growth of large-scale WSe2/SnS2 vertical bilayer p–n junctions on SiO2/Si substrates, with the lateral sizes reaching up to millimeter scale. Multi-electrode field-effect transistors have been integrated on a single heterostructure bilayer. Electrical transport measurements indicate that the field-effect transistors of the junction show an ultra-low off-state leakage current of 10−14 A and a highest on–off ratio of up to 107. Optoelectronic characterizations show prominent photoresponse, with a fast response time of 500 μs, faster than all the directly grown vertical 2D heterostructures. The direct growth of high-quality van der Waals junctions marks an important step toward high-performance integrated optoelectronic devices and systems. Growth of large area and defect-free two-dimensional semiconductor layers for high-performance p–n junction applications has been a great challenge. Yang et al. prepare millimeter-scaled WSe2/SnS2 vertical heterojunctions by two-step van der Waals epitaxy, which show excellent optoelectronic properties.