Latest ArticlesElectrochemical reduction of CO2 to value-added chemicals holds promise for carbon utilization and renewable electricity storage. However, selective CO2 reduction to multi-carbon fuels remains a significant challenge. Here, we report that B/N-doped sp3/sp2 hybridized nanocarbon (BNHC), consisting of ultra-small nanoparticles with a sp3 carbon core covered by a sp2 carbon shell, is an efficient electrocatalyst for electrochemical reduction of CO2 to ethanol at relatively low overpotentials. CO2 reduction occurs with a Faradaic efficiency of 58.8%-69.1% for ethanol and acetate production at -0.5 ~ -0.6 V (vs. RHE), among which 51.6%-56.0% is for ethanol. The high selectivity for ethanol is due to the integrated effect of sp3/sp2 carbon and B/N doping. Both sp3 carbon and B/N doping contribute to enhanced ethanol production with sp2 carbon reducing the overpotential for CO2 reduction to ethanol.
Ground-level ozone is one of the primary pollutants detrimental to human health and ecosystems. Catalytic ozone decomposition still suffers from low efficiency and unsatisfactory stability. In this work, we report a manganese-based layered double hydroxide catalyst (Co3Mn-LDH), which exhibited a superior ozone decomposition performance with the efficiency of 100% and stability over 7 h under a GHSV of 2,000,000 mL g-1h-1 and relative humidity of 15%. Even when the relative humidity increased to 50%, the ozone decomposition also reached 86%, which significantly exceeds as-synthesized MnO2 and commercial MnO2 in performance. The catalytic mechanism was studied by H2-TPR, FT-IR and XPS. The excellent performance of Co3Mn-LDH can be attributed to its abundant surface hydroxyl groups that ensured the preferentially surface enrichment of ozone, as well as the cyclic dynamic replenishment of electrons between multivalent Co2+/Co3+, Mn2+/Mn3+/Mn4+ and oxygen species that endowed the stable ozone decomposition. This work offers new insights into the design of efficient catalysts for ozone pollution control.
Solid-state batteries with high energy density and safety are promising next-generation battery systems. However, lithium oxide and lithium sulfide electrolytes suffer low ionic conductivity and poor electrochemical stability, respectively. Lithium halide solid electrolyte shows high conductivity and good compatibility with the pristine high-voltage cathode but limited applications due to the high price of rare metal. Zr-based lithium halides with low cost and high stability possess great potential. Herein, a small amount of In3+ is introduced in Li2ZrCl6 to synthesize Li2.25Zr0.75In0.25Cl6 electrolytes with a high room temperature Li-ion conductivity of 1.08 mS/cm. Solid-state batteries using Li2.25Zr0.75In0.25Cl6/Li5.5PS4.5Cl1.5 bilayer solid electrolytes combined with Li-In anode and pristine LiNi0.7Mn0.2Co0.1O2 cathode deliver high initial discharge capacities under different cut-off voltages. This work provides an effective strategy for enhancing the conductivity of Li2ZrCl6 electrolytes, promoting their applications in solid-state batteries.
Carbon dots (CDs) with intriguing fluorescent property, good biocompatibility, high stability, easy interaction with substrates, are burgeoning carbon nanoparticles with large potential in various applications. Incorporating CDs into the polymer matrix is becoming a popular strategy to endow the complex with new functions. Herein, the green-synthesized CDs was integrated into the mixture of gelatin (derived from waste fish scale) and chitosan, and a multifunctional bio-nanocomposite (defined as Gelatin/Chitosan/CDs) film was developed, which showed the excellent antibacterial, antioxidant, pH-sensitivity, UV shielding, and blue-emission properties. The effects of different concentrations of CDs on the physical, mechanical, structural, and functional activity of bio-nanocomposite film were tested. Compared with the Gelatin/Chitosan film, the Gelatin/Chitosan/CDs film with an optimum addition of 20% CDs showed the enhanced antibacterial, antioxidant as well as UV shielding activities. More importantly, it was used as an effective packaging material for fish meat preservation, reducing the loss of nutritional quality consumption, extending the shelf life of food. Besides, the bio-nanocomposite films also possessed the anti-counterfeiting and pH-responsive properties due to the strong fluorescent emission of CDs, and had the great potential in developing the intelligent packaging materials. Our work shed new light on the new application of CDs and the synthesis of bio-nanocomposite film in food industry.
Protein-based drugs have received extensive attention in the field of drug research in recent years. However, protein-based drug activity is difficult to maintain during oral delivery, which limits its application. This study developed bifunctional oral lipid polymer hybrid nanoparticles (R8-PEG-PPNPs) that deliver superoxide dismutase (SOD) for the treatment of ulcerative colitis (UC). R8-PEG-PPNPs was composed of PCADK, PLGA, lecithin, and co-modified with stearic acid-octa-arginine and polyethylene glycol. The nanoparticles (NPs) are uniformly dispersed with a complete spherical structure. In vitro stability and release studies showed that R8-PEG-PPNPs exhibited good stability and protection. In vitro cell culture experiments demonstrated that R8-PEG-PPNPs as carriers have no significant toxic effects on cells at concentration below 1000 µg/mL and promote cellular uptake. In experiments with ulcerative colitis mice, R8-PEG- PPNPs were able to enhance drug absorption by intestinal epithelial cells and accumulate effectively at the site of inflammation. Its therapeutic effect further demonstrates that R8-PEG-PPNPs are a promising delivery system for oral delivery of protein-based drugs.
During cancer treatment, chemotherapeutic drugs always result in severe side-effects and drug resistance. Therefore, combining cheomtherapy with other therapeutic modalities, such as photodynamic therapy (PDT) and designing an activable platform is promising for precise and efficient anticancer treatment. Herein, we report a "pro-drug-photosensitizer" agent, LMB-S-CPT, bearing a disulfide bond as the glutathione (GSH)-activatable linker. LMB-S-CPT can be selectively activated by GSH to release activated drug, camptothecin (CPT), for chemotherapy and activated photosensitizer, methylene blue (MB), for PDT. LMB-S-CPT exhibits excellent tumor-activatable performance when injected into tumor-bearing mice, as well as specific cancer therapy with negligible toxic side effects. The activatable pro-drug-photosensitizer offers a new strategy for chemo-photodynamic therapy and displays precise, selective and excellent antitumor effect.
Lithium–sulfur (Li–S) batteries exhibit outstanding energy density and material sustainability. Enormous effects have been devoted to the sulfur cathode to address redox kinetics and polysulfide intermediates shuttle. Recent attentions are gradually turning to the protection of the lithium metal anodes, since electrochemical performances of Li–S batteries are closely linked to the working efficiency of the anode side, especially in pouch cells that adopt stringent test protocols. This Perspective article summarizes critical issues encountered in the lithium metal anode, and outlines possible solutions to achieve efficient working lithium anode in Li–S batteries. The lithium metal anode in Li–S batteries shares the common failure mechanisms of volume fluctuation, nonuniform lithium flux, electrolyte corrosion and lithium pulverization occurring in lithium metal batteries with oxide cathodes, and also experiences unique polysulfide corrosion and massive lithium accumulation. These issues can be partially addressed by developing three-dimensional scaffold, exerting quasi-solid reaction, tailoring native solid electrolyte interphase (SEI) and designing artificial SEI. The practical evaluation of Li–S batteries highlights the importance of pouch cell platform, which is distinguished from coin-type cells in terms of lean electrolyte-to-sulfur ratio, thin lithium foil, as well as sizable total capacity and current that are loaded on pouch cells. This Perspective underlines the development of practically efficient working lithium metal anode in Li–S batteries.
Both glycosylation and phosphorylation exert crucial rule in multitudinous biological processes. For in-depth profiling of glycosylation and phosphorylation, a magnetic metal oxide is effectively coupled with inherently hydrophilic mesoporous channels (denoted as Fe3O4@TiO2@mSiO2-TSG). Based on the mechanism of hydrophilic interaction liquid chromatography (HILIC) and metal oxide affinity chromatography (MOAC), the Fe3O4@TiO2@mSiO2-TSG nanomaterial shows high capacity for simultaneously enriching glycopeptides and phosphopeptides. With human saliva collected in successive four days as practical biological sample, endogenous glycopeptides and phosphopeptides are efficiently enriched. Further gene ontology analysis reveals that the identified endogenous glycopeptides and phosphopeptides participate in diverse molecular functions and biological processes. This strategy is anticipated to promote variation analysis of salivary post-translational modifications.
Buchwald-Hartwig amination of 5, 15-dibromo and 5, 10-dibromo Ni(Ⅱ)porphyrins with 5-amino Ni(Ⅱ)porphyrin gave linear and bent trimers 4Ni and 5Ni with a central quinodiimine-type Ni(Ⅱ)porphyrinoid. The structures of 4Ni and 5Ni have been confirmed by X-ray diffraction analysis in both cases. The formation of unusual products 4Ni and 5Ni has been ascribed to facile oxidation of 5, 15- and 5, 10-amino Ni(Ⅱ) porphyrin unit. Reduction of 4Ni and 5Ni under proper conditions gave NH-bridged Ni(Ⅱ)porphyrin trimers 4Ni-2H and 5Ni-2H in high yields. Trimers 4Ni and 5Ni exhibit the lowest energy band as compared with 4Ni-2H and 5Ni-2H. Especially the bent trimer 5Ni exhibits a broad absorption tail beyond 1400 nm.
Black phosphorus (BP) has attracted an ever-growing interest due to its unique anisotropic two-dimensional structure, impressive photoelectronic properties and attractive application potential. However, the tools for bandgap engineering and passivation via covalent modification of BP nanosheets remain limited to diazonium salt and nucleophilic addition methods, so that developing new modification strategies for BP nanosheets is crucial to explore its physical and chemical properties and enrich the toolbox for functionalization. Herein, we report the covalent modification of liquid-phase exfoliated BP nanosheets based on a rational analysis of BP structure. The modification of BP is achieved via carbene, a highly reactive organic mediate. The carbene modification improves the solubility and stability of BP nanosheets. Detailed microscopic and spectroscopic characterizations including infrared spectra, Raman spectra, X-ray photoelectron spectra, SEM and TEM were conducted to provide insights for the reaction. The proof of the existence of covalent bonds between BP nanosheets and organic moieties confirms the successful modification. Moreover, theoretical calculations were conducted to unveil the reaction mechanism of the two different types of bonds and the chemical property of two-dimensional BP.