Metal-organic-framework-derived formation of Co–N-doped carbon materials for efficient oxygen reduction reaction

Non-precious metal nitrogen-doped carbonaceous materials have attracted tremendous attention in the field of electrochemical energy storage and conversion.Herein,we report the designed synthesis of a novel series of Co-N-C nanocomposites and their evaluation of electrochemical properties.Novel yolkshell structured Co nanoparticles@polymer materials are fabricated from the facile coating polymer strategy on the surface of ZIF-67.After calcination in nitrogen atmosphere,the Co–N–C nanocomposites in which cobalt metal nanoparticles are embedded in the highly porous and graphitic carbon matrix are successfully achieved.The cobalt nanoparticles containing cobalt metal crystallites with an oxidized shell and/or smaller(or amorphous)cobalt-oxide deposits appear on the surface of graphitic carbons.The prepared Co–N–C nanoparticles showed favorable electrocatalytic activity for oxygen reduction reactions,which is attributed to its high graphitic degree,large surface area and the large amount existence of Co–N active sites.

Two-dimensional metal-organic-framework as a unique theranostic nano-platform for nuclear imaging and chemo-photodynamic cancer therapy

Nanoscale metal organic frameworks (NMOFs) with porous structure and inherent biodegradability are attractive nanomedicine platforms.In addition to conventional particulate NMOFs,two-dimensional (2D) NMOFs are emerging as a unique type of NMOFs which however have been relatively less explored for nanomedicine applications.Herein,2D NMOFs composed of Zn2+ and tetrakis(4-carboxyphenyl) porphyrin (TCPP) are fabricated and functionalized with polyethylene glycol (PEG).Compared to their particulate counterpart,such 2D NMOFs show greatly increased drug loading capacity and enhanced light-triggered singlet oxygen production,promising for chemotherapy and photodynamic therapy (PDT),respectively.Utilizing the porphyrin structure of TCPP,our 2D NMOFs could be labeled with a diagnostic radioisotope,99mTc,for single photon emission computer tomography (SPECT) imaging,which reveals efficient tumor homing of those 2D NMOFs upon intravenous injection.While offering a remarkable synergistic in vivo antitumor effect for the combined chemo-PDT,such 2D NMOFs show efficient biodegradation and rapid renal clearance.Our work presents the great promise of 2D NMOFs for nanomedicine applications.

Augmenting Intrinsic Fenton-Like Activities of MOF-Derived Catalysts via N-Molecule-Assisted Self-catalyzed Carbonization

To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.

Overview of emerging catalytic materials for electrochemical green ammonia synthesis and process

The concept of“green-ammonia-zero-carbon emission”is an emerging research topic in the global community and many countries driving toward decarbonizing a diversity of applications dependent on fossil fuels.In light of this,electrochemical nitrogen reduction reaction(ENRR)received great attention at ambient conditions.The low efficiency(%)and ammonia(NH_(3))production rates are two major challenges in making a sustainable future.Besides,hydrogen evolution reaction is another crucial factor for realizing this NH_(3)synthesis to meet the large-scale commercial demand.Herein,the(i)importance of NH_(3)as an energy carrier for the next future,(ii)discussion with ENRR theory and the fundamental mechanism,(iii)device configuration and types of electrolytic systems for NH_(3)synthesis including key metrics,(iv)then moving into rising electrocatalysts for ENRR such as single-atom catalysts(SACs),MXenes,and metal–organic frameworks that were scientifically summarized,and(v)finally,the current technical contests and future perceptions are discussed.Hence,this review aims to give insightful direction and a fresh motivation toward ENRR and the development of advanced electrocatalysts in terms of cost,efficiency,and technologically large scale for the synthesis of green NH_(3).

Non-cytotoxic nanoparticles re-educating macrophages achieving both innate and adaptive immune responses for tumor therapy

Macrophages are important antigen-presenting cells to combat tumor via both innate and adaptive immunity,while they are programmed toM2 phenotype in established tumors and instead promote cancer development and metastasis.Here,we develop a nanomedicine that can re-educate M2 polarized macrophages to restore their anti-tumor activities.The nanomedicine has a core-shell structure to co-load IPI549,a PI3Kγinhibitor,and CpG,a Toll-like receptor 9 agonist.Specifically,the hydrophobic IPI549 is self-assembled into a pure drug nano-core,while MOF shell layer is coated for CpG encapsulation,achieving extra-high total drugs loading of 44%.Such nanosystem could facilitate intracellular delivery of the payloads but without any cytotoxicity,displaying excellent biocompatibility.After entering macrophages,the released IPI549 and CpG exert a synergistic effect to switch macrophages from M2 to M1 phenotype,which enables anti-tumor activities via directly engulfing tumor cells or excreting tumor killing cytokines.Moreover,tumor antigens released from the dying tumor cells could be effectively presented by the re-educated macrophages owing to the up-regulation of various antigen presenting mediators,resulting in infiltration and activation of cytotoxic T lymphocytes.As a result,the nanosystem triggers a robust antitumor immune response in combination with PD-L1 antibody to inhibit tumor growth and metastasis.This work provides a non-cytotoxic nanomedicine to modulate tumor immune microenvironment by reprograming macrophages.

MOFs derived magnetic porous carbon microspheres constructed by core-shell Ni@C with high-performance microwave absorption

Lightweight and high-performance are two determining factors for metal-organic-frameworks(MOFs)derived microwave absorbers.However,most of the reported MOFs derived absorbers usually possess high filler loading.Herein,a series of MOFs derived magnetic porous carbon microspheres with tunable diameter and high specific surface area have been synthesized via a pyrolysis process.The synthesized magnetic porous carbon microspheres,constructed by uniformly distributed core-shell Ni@C,exhibit high-performance microwave absorption with a low filler loading of 10 wt%.Considering the mciro-mesoporous structures,matched impedance,strong conductive loss,enhanced dipolar/interfacial polarization as well as strong magnetic coupling network,a minimum reflection loss of-60 dB and an absorption bandwidth of 7.0 GHz can be achieved at 2.6 mm.Moreover,the bandwidth reaches as wide as 10.2 GHz when the thickness is 4 mm.In addition,compared with other MOFs derived absorbers,this work provides us a simple strategy for the synthesis of porous carbon microspheres with lightweight and high-performance microwave absorption for practical applications.

Designing of multifunctional and flame retardant separator towards safer high-performance lithium-sulfur batteries

Owing to unprecedented merits such as high theoretical capacity,superior energy density and low cost,lithium-sulfur batteries(LSBs)show a bright future both in scientific and industrial areas.Whereas,the inherent issues,including highly insulating character,undesired shuttle behavior and lithium dendrites growth,are seriously impeding its practical usage.Here,a metal-organic-frameworks(MOFs)derived N,S co-doped carbon nanotube hollow architecture confining with CoS_(2) nanoparticles(CoS_(2)/NSCNHF)modified separator is designed to surmount these obstacles.Compared with Celgard separator,this designed separator shows obviously enhanced flame retardancy,giving 73.1%and 53.0%reductions in peak heat release rate and total heat release,separately.Concretely,its hollow structure,conductive feature,electrocatalytic activity and Lewis acid-base interaction enable the efficient inhibition on shuttle behavior as well as boost in polysulfides conversion kinetics.The cell with modified separator delivers a high discharge capacity of 1,284.5 mAh·g^(−1).After running for 100 cycles,a discharge capacity of 661.3 mAh·g^(−1) is remained.Markedly,the suppression on lithium dendrites growth is also observed,manifesting the enhanced battery safety.Overall,this work may shed light on the effective usage of MOFs-derived hierarchical composite in achieving LSBs with high electrochemical performance as well as safety.

Heterogeneous junctions of magnetic Ni core@binary dielectric shells toward high-efficiency microwave attenuation

Metal-organic-frameworks(MOFs)derived carbon-based composites with balanced impedance matching and synergistic dielectric/magnetic loss are considered as promising microwave absorbers.With the aim to promote interfacial polarization,herein,heterogeneous junctions composed of magnetic Ni core and binary dielectric shells(C and PEDOT)are synthesized by annealing Ni-MOFs precursors and an in-situ polymerization strategy,forming Ni@C@PEDOT spheres with multilayer heterogeneous interfaces.The results indicate that the final absorption attenuation is sensitive to the thickness of the dielectric PEDOT layer,when the thickness of the PEDOT layer is 224 nm,an optimal reflection loss of-72.4 d B is achieved at 2 mm and the effective absorption bandwidth reaches 6.4 GHz with a thickness of only 1.85 mm,the excellent absorption attenuation is accredited to the promoted impedance matching,enhanced conduction loss as well as the synergistic interfacial polarization induced by magnetic core and binary dielectric shells.Meanwhile,this work offers a simple and significant strategy in preparation for ideal microwave absorbers by rational design of multilayer heterogeneous interfaces.

Co/N-doped carbon nanotube arrays grown on 2D MOFs-derived matrix for boosting the oxygen reduction reaction in alkaline and acidic media

The development of high-performance and cost-effective electrocatalysts towards oxygen reduction reaction(ORR) is of significant importance,but still challenging for the practical applications in related energy systems.ORR process typically suffers from sluggish kinetics,the exploration of ORR electrocatalyst thus requires elaborate design.Herein,an effective strategy is developed for growing Co/N-doped carbon nanotube arrays on 2D MOFs-derived matrix via the pyrolysis of Co/Zn metalorganic-framework(MOF) nanosheets.The Co/Zn-MOF nanosheets serve as both the self-template for the 2D carbonized framework morphology and C/N source for the in-situ growth of 1D N-doped carbon nanotubes.The constructed hie rarchical architecture effectively integrates the OD/1D Co nanoparticle/Ndoped carbon nanotube interface and 1D(nanotubes)/2D(nanosheets) junction into frameworks with highly exposed active surface,enhanced mass-transport kinetics and electrical conductivity.As a result,the designed composite exhibits superior ORR activity and durability in alkaline media as compared to commercial Pt/C.Particularly,it shows promising ORR performance with a half-wave potential of 0.78 V versus reversible hydrogen electrode and negligible activity attenuation after 5000 potential cycles in acidic electrolyte.The designed strategy can be extended to construct other MOFs-derived carbon matrixes with diverse hierarchical structures and provide an efficient avenue for searching highperformance electrocatalysts.

Effect of organic moieties(phenyl,naphthalene,and biphenyl)in Zr-MIL-140 on the hydrogenation activity of Pd nanoparticles

MIL-140-type metal organic frameworks （isoreticular zirconium oxide MOFs） with different aromatic moieties （phenyl, naphthalene, and biphenyl） have been synthesized and employed as the supports of palladium nanoparticles （Pd NiPs）. The catalysts were characterized by XRD, BET, TEM and CO chemisorption. The results reveal that Pd NPs are homogeneously dispersed on all materials whereas different accessibility to CO is observed. The hydrogenation performance in C=C saturation with respect to the effect of the aromatic moiety is compared. The Pd/MIL-140A MOF with the highest hydrogenation activity among the three catalysts comprised of different aromatic rings points to a unique Pd-π interaction between Pd and frameworks consisting of mono-phenyl groups （C6H4）.