Copper Single Atoms Chelated on Ligand-Modified Carbon for Ullmann-type C-O Coupling

Cross-coupling reactions are of great importance in chemistry due to their ability to facilitate the construction of complex organic molecules. Among these reactions, the Ullmann-type C-O coupling between phenols and aryl halides is particularly noteworthy and useful for preparing diarylethers. However, this reaction typically relies on homogeneous catalysts that rapidly deactivate under harsh reaction conditions. In this study, we introduce a novel heterogeneous catalyst for the Ullmann-type C-O coupling reaction, comprised of isolated Cu atoms chelated to a tetraethylenepentamine-pyrrole ligand that is immobilized on graphite nanoplatelets. The catalytic study reveals the recyclability of the material, and demonstrates the crucial role of the pyrrole linker in stabilizing the Cu sites. The work expands the potential of single-atom catalyst nanoarchitectures and underscores the significance of ligands in stabilizing metals in cationic forms, providing a novel, tailored catalyst for cross-coupling chemistries.

Chemical and spatial dual-confinement engineering for stable Na-S batteries with approximately 100% capacity retention

Sodium-sulfur (Na-S) batteries are attracting intensive attention due to the merits like high energy and low cost, while the poor stability of sulfur cathode limits the further development. Here, we report a chemical and spatial dual-confinement approach to improve the stability of Na-S batteries. It refers to covalently bond sulfur to carbon at forms of C-S/N-C=S bonds with high strength for locking sulfur. Meanwhile, sulfur is examined to be S1-S2 small species produced by thermally cutting S8 large molecules followed by sealing in the confined pores of carbon materials. Hence, the sulfur cathode achieves a good stability of maintaining a high-capacity retention of 97.64% after 1000 cycles. Experimental and theoretical results show that Na+ is hosted via a coordination structure (N···Na···S) without breaking the C-S bond, thus impeding the formation and dissolution of sodium polysulfide to ensure a good cycling stability. This work provides a promising method for addressing the S-triggered stability problem of Na-S batteries and other S-based batteries.

Functional Carbon from Nature: Biomass-Derived Carbon Materials and the Recent Progress of Their Applications

Biomass is considered as a promising source to fabricate functional carbon materials for its sustainability, low cost, and high carbon content. Biomass-derived-carbon materials (BCMs) have been a thriving research field. Novel structures, diverse synthesis methods, and versatile applications of BCMs have been reported. However, there has been no recent review of the numerous studies of different aspects of BCMs-related research. Therefore, this paper presents a comprehensive review that summarizes the progress of BCMs related research. Herein, typical types of biomass used to prepare BCMs are introduced. Variable structures of BCMs are summarized as the performance and properties of BCMs are closely related to their structures. Representative synthesis strategies, including both their merits and drawbacks are reviewed comprehensively. Moreover, the influence of synthetic conditions on the structure of as-prepared carbon products is discussed, providing important information for the rational design of the fabrication process of BCMs. Recent progress in versatile applications of BCMs based on their morphologies and physicochemical properties is reported. Finally, the remaining challenges of BCMs, are highlighted. Overall, this review provides a valuable overview of current knowledge and recent progress of BCMs, and it outlines directions for future research development of BCMs.