Abstract The lithium–sulfur (Li–S) batteries are promising because of the high energy density, low cost, and natural abundance of sulfur material. Li–S batteries have suffered from severe capacity fading and poor cyclability, resulting in low sulfur utilization. Herein, S-DHCS/CNTs are synthesized by integration of a double-hollow carbon sphere (DHCS) with carbon nanotubes (CNTs), and the addition of sulfur in DHCS by melt impregnations. The proposed S-DHCS/CNTs can effectively confine sulfur and physically suppress the diffusion of polysulfides within the double-hollow structures. CNTs act as a conductive agent. S-DHCS/CNTs maintain the volume variations and accommodate high sulfur content 73 wt%. The designed S-DHCS/CNTs electrode with high sulfur loading (3.3 mg cm −2 ) and high areal capacity (5.6 mAh mg cm −2 ) shows a high initial specific capacity of 1709 mAh g −1 and maintains a reversible capacity of 730 mAh g −1 after 48 cycles at 0.2 C with high coulombic efficiency (100%). This work offers a fascinating strategy to design carbon-based material for high-performance lithium–sulfur batteries.
Phenylhydroxylamine and its derivates (PHAs) are important chemical intermediates. Phenylhydroxylamines are mainly produced via the catalytic reduction of aromatic nitro compounds. However, this catalytic reduction method prefers to generate thermodynamically stable aromatic amine. Thus, designing suitable catalytic systems, especially catalysts to selectively convert aromatic nitro compounds to PHAs, has received increasing attention but remains challenging. In this review, we initially provide a brief overview of the various strategies employed for the synthesis of PHAs, focusing on reducing aromatic nitro compounds. Subsequently, an in-depth analysis is presented on the catalytic reduction process, encompassing discussions on catalysts, reductants, hydrogen sources, and a comprehensive assessment of the merits and drawbacks of various catalytic systems. Furthermore, a concise overview is provided regarding the progress made in comprehending the mechanisms involved in this process of catalytic reduction of aromatic nitro compounds. Finally, the main challenges and prospects in PHAs' production via catalytic reduction are outlined.
Abstract We report a new approach of in situ assembling gold nanoclusters (AuNCs) into hydrogel networks by exploiting the triple roles of protein as a gelator, a reducing agent as well as a template. The strategy simply involves the mixing of BSA and AuCl 4 − under alkaline condition. The obtained AuNCs‐protein nanocomposite hydrogels with injectable and moldable features can be made into semi‐transparent films or N‐doped C/Au composites. Our work demonstrates the feasibility of fabricating AuNCs in situ embedded in hybrid hydrogels, which can serve as multifunctional precursors for constructing diverse nanocomposite materials.
Abstract The non‐noble‐metal catalysed‐multicomponent reactions between flue gas CO 2 and cheap industrial raw stocks into high value‐added fine chemicals is a promising manner for the ideal CO 2 utilization route. To achieve this, the key fundamental challenge is the rational development of highly efficient and facile reaction pathway while establishing compatible catalytic system. Herein, through the stepwise solvent‐assisted linker installation, post‐synthetic fluorination and metalation, we report the construction of a series of perfluoroalkyl‐decorated noble‐metal‐free metal–organic frameworks (MOFs) PCN‐(BPY‐CuI)‐(TPDC‐F x ) [BPY=2,2′‐bipyridine‐5,5′‐dicarboxylate, TPDC‐NH 2 =2′‐amino‐[1,1′:4′,1′′‐terphenyl]‐4,4′′‐dicarboxylic acid] that can catalyze the one‐pot four‐component reaction between alkyne, aldehyde, amine and flue gas CO 2 for the preparation of 2‐oxazolidinones. Such assembly endows the MOFs with superhydrophobic microenvironment, superior water resistance and highly stable catalytic site, leading to 21 times higher turnover numbers than that of homogeneous counterparts. Mechanism investigation implied that the substrates can be efficiently enriched by the MOF wall and then the adsorbed amine species act as an extrinsic binding site towards dilute CO 2 through their strong preferential formation to carbamate acid. Moreover, density functional theory calculations suggest the tetrahedral geometry of Cu in MOF offers special resistance towards amine poisoning, thus maintaining its high efficiency during the catalytic process.
Water-assisted proton hopping (WAPH) has been intensively investigated for promoting the performance of metal oxide-supported catalysts for hydrogenation. However, the effects of the structure of the metal oxide support on WAPH have received little attention. Herein, we construct oxygen vacancy-bearing, MoO3–x-supported Pd nanoparticle catalysts (Pd/MoO3–x-R), where the oxygen vacancies can promote WAPH, thereby facilitating catalytic hydrogenation. The experimental results and theoretical calculations show that the oxygen vacancies favor the adsorption of water, which assists the proton hopping across the surface of the metal oxide, enhancing the catalytic hydrogenation. Our finding will provide a potential approach to the design of metal oxide-supported catalysts for hydrogenation.
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