Herein, the authors report, for the first time, the semisacrificial template growth of a self‐supporting metal–organic framework (MOF) nanocomposite electrode composed of ultrasmall iron‐rich ...Fe(Ni)‐MOF cluster‐decorated ultrathin Ni‐rich Ni(Fe)‐MOF nanosheets from the NiFe alloy foam, in which the Fe(Ni)‐MOF clusters are uniform with a particle size of 2–5 nm, while the thickness of the Ni(Fe)‐MOF nanosheets is only about 1.56 nm. When directly used as a self‐supported working electrode for the oxygen evolution reaction (OER), it can afford an impressive electrocatalytic performance with required overpotentials of 227 and 253 mV to achieve current densities of 10 and 100 mA cm−2, respectively, much outperforming the benchmark of RuO2 and most state‐of‐the‐art noble‐metal‐free catalysts. Characterizations demonstrated that the combination of the unique nanostructure of the catalyst and the strong coupling effect between Ni and Fe active sites should be responsible for its excellent OER performance. Remarkably, when coupled with a Pt electrode in an overall water splitting system, they only needed 1.537 V to achieve a current density of 10 mA cm−2. The facile and economical methodology represents a new way to design and prepare high‐performance self‐supporting MOF electrocatalysts for highly efficient electrochemical processes.
A self‐supporting MOF nanocomposite electrode composed of ultrasmall iron‐rich Fe(Ni)‐MOF cluster‐decorated ultrathin Ni‐rich Ni(Fe)‐MOF nanosheets is prepared by a semisacrificial template growth method. The combination of the unique nanostructure and the strong coupling effect between Ni and Fe active sites endow the composite electrode with excellent electrocatalytic oxygen evolution reaction performance.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Electrochemical reduction of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide ...potential window is challenging. Herein, atomically thin bismuthene (Bi‐ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth‐based metal–organic layers. The few‐layer Bi‐ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm−2 without compromising selectivity in a flow‐cell reactor. Using in situ ATR‐IR spectra and DFT analysis, a reaction mechanism involving HCO3− for formate generation was unveiled, which brings new fundamental understanding of CO2 reduction.
Atomically thin bismuthene with excellent electrocatalytic CO2 reduction performance is obtained from ultrathin metal–organic layers by an in situ electrochemical transformation process. A reaction route involving HCO3− for formate production is revealed.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Hypoxia occurs naturally at high-altitudes and pathologically in hypoxic solid tumors. Here, we report that genes involved in various human cancers evolved rapidly in Tibetans and six Tibetan ...domestic mammals compared to reciprocal lowlanders. Furthermore, m
A modified mRNA binding protein YTHDF1, one of evolutionary positively selected genes for high-altitude adaptation is amplified in various cancers, including non-small cell lung cancer (NSCLC). We show that YTHDF1 deficiency inhibits NSCLC cell proliferation and xenograft tumor formation through regulating the translational efficiency of CDK2, CDK4, and cyclin D1, and that YTHDF1 depletion restrains de novo lung adenocarcinomas (ADC) progression. However, we observe that YTHDF1 high expression correlates with better clinical outcome, with its depletion rendering cancerous cells resistant to cisplatin (DDP) treatment. Mechanistic studies identified the Keap1-Nrf2-AKR1C1 axis as the downstream mediator of YTHDF1. Together, these findings highlight the critical role of YTHDF1 in both hypoxia adaptation and pathogenesis of NSCLC.
Reported herein are two new polymorphic Co‐MOFs (CTGU‐5 and ‐6) that can be selectively crystallized into the pure 2D or 3D net using an anionic or neutral surfactant, respectively. Each polymorph ...contains a H2O molecule, but differs dramatically in its bonding to the framework, which in turn affects the crystal structure and electrocatalytic performance for hydrogen evolution reaction (HER). Both experimental and computational studies find that 2D CTGU‐5 which has coordinates water and more open access to the cobalt site has higher electrocatalytic activity than CTGU‐6 with the lattice water. The integration with co‐catalysts, such as acetylene black (AB) leads to a composite material, AB&CTGU‐5 (1:4) with very efficient HER catalytic properties among reported MOFs. It exhibits superior HER properties including a very positive onset potential of 18 mV, low Tafel slope of 45 mV dec−1, higher exchange current density of 8.6×10−4 A cm−2, and long‐term stability.
HER choice of surfactants: Two new Co‐MOFs phase‐selected by anionic and neutral surfactants exhibit differential affinity for entrapped water molecules, leading to a difference in the spatial accessibility of active metal sites. A composite material made from such Co‐MOFs shows impressive performance in electrocatalytic hydrogen evolution reaction (HER) as well as long‐term stability.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Electrosynthesis of formic acid/formate is a promising alternative protocol to industrial processes. Herein, a pioneering pair‐electrosynthesis tactic is reported for exclusively producing formate ...via coupling selectively electrocatalytic methanol oxidation reaction (MOR) and CO2 reduction reaction (CO2RR), in which the electrode derived from Ni‐based metal–organic framework (Ni‐MOF) nanosheet arrays (Ni‐NF‐Af), as well as the Bi‐MOF‐derived ultrathin bismuthenes (Bi‐enes), both obtained through an in situ electrochemical conversion process, are used as efficient anodic and cathodic electrocatalysts, respectively, achieving concurrent yielding of the same high‐value product at both electrodes with greatly reduced energy input. The as‐prepared Ni‐NF‐Af only needs quite low potentials to reach large current densities (e.g., 100 mA cm−2@1.345 V) with ≈100% selectivity for anodic methanol‐to‐formate conversion. Meanwhile, for CO2RR in the cathode, the as‐prepared Bi‐enes can simultaneously exhibit near‐unity selectivity, large current densities, and good stability in a wide potential window toward formate production. Consequently, the coupled MOR//CO2RR system based on the distinctive MOF‐derived catalysts displays excellent performance for pair‐electrosynthesis of formate, delivering high current densities and nearly 100% selectivity for formate production in both the anode and the cathode. This work provides a novel way to design advanced MOF‐derived electrocatalysts and innovative electrolytic systems for electrochemical production of value‐added feedstocks.
A pair‐electrosynthesis tactic for concurrent formate production is pioneeringly developed by coupling electrocatalytic methanol oxidation and CO2 reduction reactions, which can achieve highly efficient and selective value‐added synthesis in both electrodes with lower energy consumption, using in situ metal–organic‐framework‐derived high‐performance 2D electrocatalysts.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Administration of exosomes derived from mesenchymal stromal cells (MSCs) could improve some neurologic conditions by transferring functional biomolecules to recipient cells. Furthermore, exosomes ...from hypoxic progenitor cells exerted better therapeutic effects in organ injury through specific cargoes. However, there are no related reports about whether exosomes derived from MSCs or hypoxia‐preconditioned MSCs (PC‐MSCs) could prevent memory deficits in Alzheimer disease (AD). In this study, the exosomes derived from MSCs or PC‐MSCs were systemically administered to transgenic APP/PS1 mice. The expression of miR‐21 in MSCs was significantly increased after hypoxic treatment. Injection of exosomes from normoxic MSCs could rescue cognition and memory impairment according to results of the Morris water maze test, reduced plaque deposition, and Aβ levels in the brain; could decrease the activation of astrocytes and microglia; could down‐regulate proinflammatory cytokines (TNF‐α and IL‐1β); and could up‐regulate anti‐inflammatory cytokines (IL‐4 and ‐10) in AD mice, as well as reduce the activation of signal transducer and activator of transcription 3 (STAT3) and NF‐κB. Compared to the group administered exosomes from normoxic MSCs, in the group administered exosomes from PC‐MSCs, learning and memory capabilities were significantly improved; the plaque deposition and Aβ levels were lower, and expression of growth‐associated protein 43, synapsin 1, and IL‐10 was increased; and the levels of glial fibrillary acidic protein, ionized calcium‐binding adaptor molecule 1, TNF‐α, IL‐1β, and activation of STAT3 and NF‐κB were sharply decreased. More importantly, exosomes from PC‐MSCs effectively increased the level of miR‐21 in the brain of AD mice. Additionally, replenishment of miR‐21 restored the cognitive deficits in APP/PS1 mice and prevented pathologic features. Taken together, these findings suggest that exosomes from PC‐MSCs could improve the learning and memory capabilities of APP/PS1 mice, and that the underlying mechanism may lie in the restoration of synaptic dysfunction and regulation of inflammatory responses through regulation of miR‐21.—Cui, G.‐H., Wu, J., Mou, F.‐F., Xie, W.‐H., Wang, F.‐B., Wang, Q.‐L., Fang, J., Xu, Y.‐W., Dong, Y.‐R., Liu, J.‐R., Guo, H.‐D. Exosomes derived from hypoxia‐preconditioned mesenchymal stromal cells ameliorate cognitive decline by rescuing synaptic dysfunction and regulating inflammatory responses in APP/PS1 mice. FASEB J. 32, 654–668 (2018). www.fasebj.org
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Controllable synthesis of ultrathin metal–organic framework (MOF) nanosheets and rational design of their nano/microstructures in favor of electrochemical catalysis is critical for their renewable ...energy applications. Herein, an in situ growth method is proposed to prepare the ultrathin NiFe MOF nanosheets with a thickness of 1.5 nm, which are vertically inlaid into a 3D ordered macroporous structure of NiFe hydroxide. The well‐designed composite delivers an efficient electrocatalytic performance with a low overpotential of 270 mV at a current density of 10 mA cm−2 and stable electrolysis as long as 10 h toward the electrochemical oxygen evolution reaction, much superior to the state‐of‐the‐art RuO2 electrocatalyst. A comprehensive analysis demonstrates that the excellent performance originates from the desirable combination of the highly exposed active centers in the ultrathin bimetallic MOF nanosheets, effective electron conduction between MOF nanosheets and ordered macroporous hydroxide, and efficient mass transfer across the hierarchically porous hybridization. This study sheds light on the exploration of powerful protocols to gain diverse high‐performance MOF nanosheets and may open a perspective to achieve their efficient electrocatalytic performance.
Ultrathin NiFe metal–organic framework nanosheets with a thickness of ≈1.5 nm inlaid into 3D ordered macroporous hydroxide are prepared by an in situ growth method, of which the distinctively hierarchical nanostructure affords a remarkable electrocatalytic performance for oxygen evolution reaction.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The morphology and active site engineering of electrocatalysts is an efficient strategy to improve the intrinsic activity and selectivity of electrocatalytic CO2 reduction. Here the ultralong and ...thin Bi nanobelts (Bi‐NBs) are fabricated, which feature a high edge‐to‐facet ratio and high‐degree connectivity is inherited from the ultrahigh‐aspect‐ratio crystalline bismuth−organic hybrid nanobelts, through a cathodically in situ reconstruction process. The unique nanostructure of Bi‐NBs leads to a significantly enhanced performance for electrocatalytic CO2 reduction with a near‐unity formate selectivity and high formate partial current density, which is far superior to those of the discrete Bi counterparts with low edge‐to‐facet ratios. Notably, Bi‐NBs perform ultrahigh formate selectivity over a broad potential window with a high current density reaching 400 mA cm−2 for formate production in a flow cell. Moreover, it is ultrastable to continuous electrolysis for nearly 23 h at 200 mA cm−2 without compromising the selectivity. Based on calculations, the enhanced performance is closely related to the high edge‐to‐facet ratio of Bi‐NBs, since the rich edge sites are conducive to the stabilization of the key *OCHO intermediate for formate production. In addition, the ultralong and interconnected Bi‐NBs provide “expressways” for electron transfer during CO2 electroreduction, further contributing to the improved performance.
Thin Bi nanobelts inheriting the high edge‐to‐facet ratio and high‐degree connectivity are fabricated by cathodical in situ conversion of bismuth–organic hybrid nanobelts. Such distinctive structure is conducive to stabilization of the key *OCHO intermediate for formate production and acts as “expressways” for electron transfer leading to an excellent electrocatalytic performance toward electrocatalytic CO2 reduction to formate.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Cu‐based metal–organic frameworks have attracted much attention for electrocatalytic CO2 reduction, but they are generally instable and difficult to control the product selectivity. We report ...flexible Cu(I) triazolate frameworks as efficient, stable, and tunable electrocatalysts for CO2 reduction to C2H4/CH4. By changing the size of ligand side groups, the C2H4/CH4 selectivity ratio can be gradually tuned and inversed from 11.8 : 1 to 1 : 2.6, giving C2H4, CH4, and hydrocarbon selectivities up to 51 %, 56 %, and 77 %, respectively. After long‐term electrocatalysis, they can retain the structures/morphologies without formation of Cu‐based inorganic species. Computational simulations showed that the coordination geometry of Cu(I) changed from triangular to tetrahedral to bind the reaction intermediates, and two adjacent Cu(I) cooperated for C−C coupling to form C2H4. Importantly, the ligand side groups controlled the catalyst flexibility by the steric hindrance mechanism, and the C2H4 pathway is more sensitive than the CH4 one.
Flexible Cu(I) triazolate frameworks functionalized with dinuclear copper sites can serve as highly stable and efficient electrocatalysts for CO2 reduction to C2H4/CH4, and the selectivity is tunable by the size of uncoordinated ligand side groups.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
C1q/tumor necrosis factor (TNF)-related protein 12 (CTRP12) is a secretory protein that participates in the regulation of glucose and lipid metabolism in obesity and diabetes. Its role in ...cardiovascular disease, particularly sepsis-induced cardiac injury, is unclear. Here, we stimulated cardiomyocytes with lipopolysaccharide (LPS) to establish an in vitro cardiomyocyte injury model and CTRP12 was overexpressed with an adenovirus delivery system. Overexpression of CTRP12 reduced the transcription and release of pro-inflammatory cytokines from LPS-stimulated cardiomyocytes, including TNFα, interleukin-1 (IL-1), and IL-6. Reactive oxygen species (ROS) level increased and the oxidation/redox system was disturbed in LPS-stimulated cardiomyocytes, as evident from the decrease in superoxide dismutase activity and an increase in reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and malondialdehyde level. CTRP12 overexpression decreased the increasing level of ROS and ameliorated the unbalance in the oxidation/redox system in LPS-stimulated cardiomyocytes. The viability of cardiomyocytes decreased after LPS stimulation, and the cells underwent apoptosis. CTRP12-overexpressing cardiomyocytes showed a decrease in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cells, and the ratio of B cell lymphoma (Bcl)-1/Bax in these cells was recovered. In comparison with the control group, LPS-stimulated cardiomyocytes showed reduced expression of nuclear factor E2-related factor 2 (NRF2), while CTRP12-overexpressing cardiomyocytes showed elevated NRF2 expression. Small-interfering RNA-mediated silencing of NRF2 expression in cardiomyocytes resulted in the inhibition of the protective effects of CTRP12. Thus, CTRP12 ameliorated injury in LPS-stimulated cardiomyocytes in an NRF2-dependent manner.
PDF
