Atomically dispersed metal–nitrogen–carbon (M–N–C) catalysts have emerged as the promising alternative to replace platinum-based catalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, their practical applications are restricted by the relatively low intrinsic activity, low utilization rate, and poor stability of atomic metal sites. Herein, we propose a simple but efficient strategy to synthesize a geometrically deformed single Fe site catalyst (d-SA-FeNC) by trace NaCl-coating-assisted pyrolysis of Fe-containing zeolitic imidazolate frameworks. Benefiting from the significantly exposed Fe-N4 active sites and enhanced mass transport by the hierarchically porous structure, the newly developed catalysts exhibit improved ORR performance in acidic media. Remarkably, the as-constructed membrane electrode assemblies achieve high peak power densities of 0.904 and 0.502 W cm–2 in H2–O2 and H2–air PEMFCs even at a low catalyst loading of 1 mg cm–2, respectively, revealing ultrahigh mass activity density. Both experimental and theoretical results reveal that the enhanced intrinsic activity is attributed to the synergy of deformed Fe-N4 moieties and the surrounding graphitic N dopant. In addition, the locally increased graphitization of the carbon matrix can efficiently reduce carbon corrosion, thereby promoting catalyst stability. This work provides useful guidance for the development of highly efficient ORR catalysts for PEMFCs.
Non-small cell lung cancer (NSCLC) is a prevalent subtype of lung cancer, whose mortality is high. Long non-coding RNAs (lncRNAs) have caught rising attentions because of their intricate roles in regulating cancerization and cancer progression. Long intergenic non-protein coding RNA 461 (LINC00461) has recently shown oncogenic potential in several cancers, but the function of LINC00461 in NSCLC remains to be investigated. Our study planned to unveil the regulatory role of LINC00461 in NSCLC. It was validated that LINC00461 was highly expressed in NSCLC tissues and cell lines and exhibited prognostic significance. Furthermore, LINC00461 expression in advanced stage was much higher than in early stage. Loss-of-function experiments suggested that LINC00461 knockdown impaired cell proliferation, migration, and epithelial-to-mesenchymal transition (EMT). Subcellular fractionation revealed the predominant location of LINC00461 in cytoplasm. Mechanistically, LINC00461 up-regulated E2F transcription factor 1 (E2F1) expression through sponging miR-4478. Besides, E2F1 bound to the promoter of LINC00461 to induce its transcription. Finally, rescue experiments verified that LINC00461 aggravated proliferation, migration, and EMT through targeting miR-4478/E2F1 axis. In consequence, the present study illustrated that LINC00461/miR-4478/E2F1 feedback loop promoted NSCLC cell proliferation and migration, providing a new prognostic marker for NSCLC.
Here, we report a conceptual strategy for introducing spatial sulfur (S)–bridge ligands to regulate the coordination environment of Fe-Co-N dual-metal centers (Spa-S-Fe,Co/NC). Benefiting from the electronic modulation, Spa-S-Fe,Co/NC catalyst showed remarkably enhanced oxygen reduction reaction (ORR) performance with a half-wave potential ( E 1/2 ) of 0.846 V and satisfactory long-term durability in acidic electrolyte. Combined experimental and theoretical studies revealed that the excellent acidic ORR activity with a remarkable stability observed for Spa-S-Fe,Co/NC is attributable to the optimal adsorption-desorption of ORR oxygenated intermediates achieved through charge-modulation of Fe-Co-N bimetallic centers by the spatial S-bridge ligands. These findings provide a unique perspective to regulate the local coordination environment of catalysts with dual-metal-centers to optimize their electrocatalytic performance.
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