Metal-organic Frameworks Derived Cobalt Encapsulated in Nitrogen-doped Porous Carbon Nanosheets for Oxygen Reduction Reaction and Rechargeable Zinc-air Batteries

Nitrogen(N)-doped carbon nanosheets(TCM-900)were prepared by pyrolyzing the cobalt metal organic framework(MOF)and acid treatment.The TCM-900 showed outstanding ORR performance with half-potential of 0.805 V.The density function theory(DFT)reveals the nitrogen activates the carbon atoms in the framework.The homemade ZAB with TCM-900 as ORR electrocatalyst exhibits high-power density of 45 mW·cm^(-2) and excellent long recharge cycling stability compared to Pt/C at 10 mA·cm^(-2).This work illustrates an attractive future of the rechargeable ZAB.

Bimetallic organic frameworks derived CuNi/carbon nanocomposites as efficient electrocatalysts for oxygen reduction reaction

Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elusive. This work used metal-organic frameworks to synthesize non-precious bimetallic carbon nanocomposites as efficient ORR catalysts. Although carbon-based Cu and Ni are good candidates, the hybrid nanocomposites take advantage of both metals to improve catalytic activity. The resulting molar ratio of Cu/Ni in the nanocomposites can be finely controlled by tuning the recipe of the precursors. Nanocom- posites with a series of molar ratios were produced, and they exhibited much better ORR catalytic performance than their monometallic counterparts in terms of limited current density, onset potential and half-wave potential. In addition, their extraordinary stability in alkaline is superior to that of commercially-available Pt-based materials, which adds to the appeal of the bimetallic carbon nanocomposites as ORR catalysts. Their improved performance can be attributed to the synergetic effects of Cu and Ni, and the enhancement of the carbon matrix.

Simultaneous improvement to solubility and bioavailability of active natural compound isosteviol using cyclodextrin metal-organic frameworks

Cyclodextrin metal-organic framework(CD-MOF)as a highly porous supramolecular carrier could be one of the solutions to the insolubility of isosteviol(STV).The solubility of STV was lower than20.00 ng/mL at pH 1.0 and pH 4.5,whilst its solubility increased to 20,074.30 ng/mL at pH 6.8 and129.58 ng/mL in water with a significant pH-dependence.The in vitro release profiles of STV from STV@CD-MOF(0.5:1)were pH-independent in distinct pH media and closed to be thoroughly released but no such release profiles were observed for STV@CD-MOF(1:1)owing to nanoclusters formation.The bioavailability of STV@CD-MOF(1:1)in rats was 8.67-fold higher than that of STV,and was1.32-and 1.27-fold higher than that of STV@CD and STV@CD-MOF(0.5:1).Our results indicated that the inclusion mechanism played a primary role when STV in CD-MOF was at a low loading ratio,while the increasement in bioavailability at a high loading ratio,which was attributed to the nanocluster mechanism.This was confirmed by molecular simulation.In conclusion,CD-MOF is a promising system for STV loading,overcoming the insolubility and to improve the bioavailability of this natural compound.

Glycoside scutellarin enhanced CD-MOF anchoring for laryngeal delivery

It is essential to develop new carriers for laryngeal drug delivery in light of the lack of therapy in laryngeal related diseases.When the inhalable micron-sized crystals ofγ-cyclodextrin metal-organic framework(CD-MOF)was utilized as dry powder inhalers(DPIs)carrier with high fine particle fraction(FPF),it was found in this research that the encapsulation of a glycoside compound,namely,scutellarin(SCU)in CD-MOF could significantly enhance its laryngeal deposition.Firstly,SCU loading into CD-MOF was optimized by incubation.Then,a series of characterizations were carried out to elucidate the mechanisms of drug loading.Finally,the laryngeal deposition rate of CD-MOF was 57.72±2.19%improved by SCU,about two times higher than that of CD-MOF,when it was determined by Next Generation Impactor(NGI)at 65 L/min.As a proof of concept,pharyngolaryngitis therapeutic agent dexamethasone(DEX)had improved laryngeal deposition after being co-encapsulated with SCU in CDMOF.The molecular simulation demonstrated the configuration of SCU in CD-MOF and its contribution to the free energy of the SCU@CD-MOF,which defined the enhanced laryngeal anchoring.In conclusion,the glycosides-like SCU could effectively enhance the anchoring of CD-MOF particles to the larynx to facilitate the treatment of laryngeal diseases.

N-doped C-coated MoO_(2)/ZnIN_(2)S_(4)heterojunction for efficient photocatalytic hydrogen production

Designing a heterojunction photocatalyst to improve the separation efficiency of photogenerated electrons and holes is of great significance to improve the hydrogen production efficiency.In this work,we report a rational design to grow ZnIN_(2)S_(4)on Mo-MOF-derived N-doped C-coated MoO_(2)(MOZIS),and it has excellent photocatalytic hydrogen production with triethanolamine(TEOA)as sacrificial agent.N-doped C improves the electron transport efficiency between MoO_(2)and ZnIN_(2)S_(4)·The systematic study shows that MOZIS has good properties to promote the effective separation and transfer of photocatalytic charges,which is attributed to the tight contact interface and good energy band structure between MoO_(2)and ZnlN_(2)S_(4).The optimized nanocomposites have a high hydrogen production efficiency of 10.89 mmol·g^(-1)(4 h)under visible light.MOF-derived N-doped C-coated MoO_(2)is an effective strategy to improve the photocatalytic hydrogen production efficiency of ZnIN_(2)S_(4).