Increasing demand for sustainable and clean energy is calling for the next‐generation energy conversion and storage technologies such as fuel cells, water electrolyzers, CO2/N2 reduction ...electrolyzers, metal–air batteries, etc. All these electrochemical processes involve oxygen electrocatalysis. Boosting the intrinsic activity and the active‐site density through rational design of metal–organic frameworks (MOFs) and metal–organic gels (MOGs) as precursors represents a new approach toward improving oxygen electrocatalysis efficiency. MOFs/MOGs afford a broad selection of combinations between metal nodes and organic linkers and are known to produce electrocatalysts with high surface areas, variable porosity, and excellent activity after pyrolysis. Some recent studies on MOFs/MOGs for oxygen electrocatalysis and their new perspectives in synthesis, characterization, and performance are discussed. New insights on the structural and compositional design in MOF/MOG‐derived oxygen electrocatalysts are summarized. Critical challenges and future research directions are also outlined.
Boosting the intrinsic activity and the active‐site density through rational design of metal–organic frameworks (MOFs) and metal–organic gels (MOGs) as precursors represents a new approach of improving oxygen electrocatalysis efficiency. Several key compositional and structural considerations for the MOF/MOG design and new perspectives between synthesis, characterization, and performance are comprehensively discussed.
Numerous efficient synthetic methods for enantioselective indole functionalizations have emerged in recent years. This review summarizes the major achievements in the transition-metal-catalyzed ...enantioselective indole functionalization reactions since 2010 and focuses on C-C bond formation processes, including alkylations, arylations, cycloaddition reactions, and other reactions. It intends to give a compendious overview of the significant progress achieved in this area.
Recent progress on the transition-metal-catalyzed enantioselective functionalization reaction of indoles is reviewed, which is mainly focused on asymmetric indole alkylations, arylations, cycloaddition reactions, and other reactions.
Herbal medicines (HMs) are much appreciated for their significant contribution to human survival and reproduction by remedial and prophylactic management of diseases. Defining the scientific basis of ...HMs will substantiate their value and promote their modernization. Ever‐increasing evidence suggests that gut microbiota plays a crucial role in HM therapy by complicated interplay with HM components. This interplay includes such activities as: gut microbiota biotransforming HM chemicals into metabolites that harbor different bioavailability and bioactivity/toxicity from their precursors; HM chemicals improving the composition of gut microbiota, consequently ameliorating its dysfunction as well as associated pathological conditions; and gut microbiota mediating the interactions (synergistic and antagonistic) between the multiple chemicals in HMs. More advanced experimental designs are recommended for future study, such as overall chemical characterization of gut microbiota‐metabolized HMs, direct microbial analysis of HM‐targeted gut microbiota, and precise gut microbiota research model development. The outcomes of such research can further elucidate the interactions between HMs and gut microbiota, thereby opening a new window for defining the scientific basis of HMs and for guiding HM‐based drug discovery.
Hybrid free‐space optical and radio frequency (FSO/RF) systems have attracted much attention for more than a decade because of their enhanced reliability and capacity as comparison to single FSO or ...RF systems. Existing schemes to construct such a hybrid system are usually to use either switching or encoding/decoding strategies for combination of channels. The proposed scheme, based on packet sharing strategy of Ethernet link aggregation, provides a different way to combine FSO and RF channels. Theoretical analysis and Experimental results show that the proposed scheme does enhance the reliability and utilize both channel capacities for a multi‐channel system. Moreover, this scheme is simple and scalable because more channels can be combined based on such a packet sharing strategy without modifying the physical channel structures, therefore, this scheme may provide a good solution for constructing an efficient and cost‐effective hybrid FSO/RF system.
Existing schemes to construct hybrid FSO/RF systems are usually to use either switching or encoding/decoding strategies for combination of channels. The proposed scheme, based on packet sharing strategy of Ethernet link aggregation, provides a different way to combine FSO and RF channels. Inner mechanism and experimental results show that this new approach enhances the reliability and can utilize both channel capacities.
Despite rapid advances in modern medical technology and significant improvements in survival rates of many cancers, pancreatic cancer is still a highly lethal gastrointestinal cancer with a low ...5-year survival rate and difficulty in early detection. At present, the incidence and mortality of pancreatic cancer are increasing year by year worldwide, no matter in the United States, Europe, Japan, or China. Globally, the incidence of pancreatic cancer is projected to increase to 18.6 per 100000 in 2050, with the average annual growth of 1.1%, meaning that pancreatic cancer will pose a significant public health burden. Due to the special anatomical location of the pancreas, the development of pancreatic cancer is usually diagnosed at a late stage with obvious clinical symptoms. Therefore, a comprehensive understanding of the risk factors for pancreatic cancer is of great clinical significance for effective prevention of pancreatic cancer. In this paper, the epidemiological characteristics, developmental trends, and risk factors of pancreatic cancer are reviewed and analyzed in detail.
An efficient genome-scale editing tool is required for construction of industrially useful microbes. We describe a targeted, continual multigene editing strategy that was applied to the Escherichia ...coli genome by using the Streptococcus pyogenes type II CRISPR-Cas9 system to realize a variety of precise genome modifications, including gene deletion and insertion, with a highest efficiency of 100%, which was able to achieve simultaneous multigene editing of up to three targets. The system also demonstrated successful targeted chromosomal deletions in Tatumella citrea, another species of the Enterobacteriaceae, with highest efficiency of 100%.
Manipulation of long‐lived triplet excitons in organic molecules is key to applications including next‐generation optoelectronics, background‐free bioimaging, information encryption, and photodynamic ...therapy. However, for organic room‐temperature phosphorescence (RTP), which stems from triplet excitons, it is still difficult to simultaneously achieve efficiency and lifetime enhancement on account of weak spin–orbit coupling and rapid nonradiative transitions, especially in the red and near‐infrared region. Herein, we report that a series of fluorescent naphthalimides—which did not originally show observable phosphorescence in solution, as aggregates, in polymer films, or in any other tested host material, including heavy‐atom matrices at cryogenic temperatures—can now efficiently produce ultralong RTP (ϕ=0.17, τ=243 ms) in phthalimide hosts. Notably, red RTP (λRTP=628 nm) is realized at a molar ratio of less than 10 parts per billion, demonstrating an unprecedentedly low guest‐to‐host ratio where efficient RTP can take place in molecular solids.
A series of fluorescent naphthalimides, which did not originally show observable phosphorescence, can now efficiently produce ultralong room‐temperature phosphorescence (RTP) in phthalimide hosts. In particular, red RTP is realized by doping at a guest‐to‐host ratio at the 10 parts‐per‐billion (ppb) level.
Dual metal–organic frameworks (MOFs, i.e., MIL‐100(Fe) and ZIF‐8) are thermally converted into Fe–Fe3C‐embedded Fe–N‐codoped carbon as platinum group metal (PGM)‐free oxygen reduction reaction (ORR) ...electrocatalysts. Pyrolysis enables imidazolate in ZIF‐8 rearranged into highly N‐doped carbon, while Fe from MIL‐100(Fe) into N‐ligated atomic sites concurrently with a few Fe–Fe3C nanoparticles. Upon precise control of MOF compositions, the optimal catalyst is highly active for the ORR in half‐cells (0.88 V in base and 0.79 V versus RHE in acid in half‐wave potential), a proton exchange membrane fuel cell (0.76 W cm−2 in peak power density) and an aprotic Li–O2 battery (8749 mAh g−1 in discharge capacity), representing a state‐of‐the‐art PGM‐free ORR catalyst. In the material, amorphous carbon with partial graphitization ensures high active site exposure and fast charge transfer simultaneously. Macropores facilitate mass transport to the catalyst surface, followed by oxygen penetration in micropores to reach the infiltrated active sites. Further modeling simulations shed light on the true Fe–Fe3C contribution to the catalyst performance, suggesting Fe3C enhances oxygen affinity, while metallic Fe promotes *OH desorption as the rate‐determining step at the nearby Fe–N–C sites. These findings demonstrate MOFs as model system for rational design of electrocatalyst for energy‐based functional applications.
An Fe–N–C catalyst is derived from dual metal–organic frameworks through facile pyrolysis, affording excellent oxygen reduction catalytic performance in alkaline/acidic half‐cells, a H2–O2 proton exchange membrane fuel cell, and a Li–O2 battery. The excellent catalytic performance benefits from density populated Fe–Fe3C@Fe–N–C dual active sites, hierarchical porosities for mass transport, and partial carbon graphitization for charge transfer.
The rapidly increasing severity of the energy crisis and environmental degradation are stimulating the rapid development of photocatalysts and rechargeable lithium/sodium ion batteries. In ...particular, MoS2/TiO2 based nanocomposites show great potential and have been widely studied in the areas of both photocatalysis and rechargeable lithium/sodium ion batteries due to their superior combination properties. In addition to the low-cost, abundance, and high chemical stability of both MoS2 and TiO2, MoS2/TiO2 composites also show complementary advantages. These include the strong optical absorption of TiO2vs. the high catalytic activity of MoS2, which is promising for photocatalysis; and excellent safety and superior structural stability of TiO2vs. the high theoretic specific capacity and unique layered structure of MoS2, thus, these composites are exciting as anode materials. In this review, we first summarize the recent progress in MoS2/TiO2-based nanomaterials for applications in photocatalysis and rechargeable batteries. We highlight the synthesis, structure and mechanism of MoS2/TiO2-based nanomaterials. Then, advancements and strategies for improving the performance of these composites in photocatalytic degradation, hydrogen evolution, CO2 reduction, LIBs and SIBs are critically discussed. Finally, perspectives on existing challenges and probable opportunities for future exploration of MoS2/TiO2-based composites towards photocatalysis and rechargeable batteries are presented. We believe the present review would provide enriched information for a deeper understanding of MoS2/TiO2 composites and open avenues for the rational design of MoS2/TiO2 based composites for energy and environment-related applications.
In the past few decades, great effort has been made toward the preparation and development of advanced transition metal dichalcogenide (TMD) materials for anodes of alkali metal ion batteries ...(AMIBs). However, their electrochemical performance is still severely impaired by structural aggregation and fracture during the conversion reaction. To address these issues, various methodologies for the fabrication of hierarchical and hybrid nanostructures, with optimization of materials and electrodes, have been fully investigated and reviewed. As regards tuning the TMD-based materials, extensive efforts have been undertaken toward optimization of their intrinsic structure at the atomic level, including surface defects, interlayer spacing expansion, phase control, alloying, and heteroatom doping. However, the design strategies and methods to manipulate the intrinsic structures and electrochemical mechanisms in AMIBs have not been fully summarized. This review provides a well-timed and critical appraisal of recent advances in the engineering of TMDs at the atomic level for AMIBs, by combining computational and experimental approaches. The correlation between these strategies and electrochemical performance is highlighted. The challenges and opportunities in this research field are also outlined. We expect that this review would be beneficial for improving the overall knowledge on the charge storage mechanisms in TMDs and for pointing out the importance of intrinsic structure engineering for enhancing the performance of TMDs in energy storage.
This review provides enriched information for understanding the charge storage mechanisms of transition metal dichalcogenides (TMDs), as well as the importance of intrinsic structure engineering for enhancing the performance of TMDs in energy storage.
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