Therefore, it is necessary to develop highperformance energy storage devices for facilitating the effective utilization of intermittent renewable energy sources. [7][8][9] Among varieties of electrochemical energy storage devices, supercapacitors (known as electrochemical capacitors) [10,11] and some rechargeable batteries (lithium-ion batteries (LIBs), lithiumsulfur (Li-S) batteries, and metal-O 2 batteries) [12][13][14][15] are at the frontier, because they can transport high power and store high energy. Nowadays, they play an indispensable role in our daily life by powering numerous portable electronic devices (e.g., cell phones and laptops), hybrid electric vehicles, and large-scale electrical grids. [16][17][18][19] It is well accepted that the performance of energy storage devices mainly depended on their electrode materials. [20,21] Owing to the advantages of large surface area, light weight, good electrical conductivity, and high thermal/ chemical stability, carbon materials have been considered as the most important electrode materials of supercapacitors and rechargeable batteries [8,20,21] Hence, various nanostructured carbons, such as carbon/graphene quantum dots, [22,23] carbon nanofiber (CNFs), [16,24] carbon nanotubes (CNTs), [13,25] graphene [26][27][28][29][30][31][32] carbon nanosheets, [33,34] 3D carbon nanostructures, [35][36][37] and porous carbon, [38,39] have gained great attention. Among these materials, 3D carbon nanomaterials have some advantages. The interlinked architecture not only shortens transport distances for ions in the well-interconnected wall structure, but also provides a continuous pathway endowing for the fast electron transport. [40] Moreover, the structural interconnectivities guarantee higher electrical conductivity and better mechanical stability. [36,41] Thereby, the design and fabrication of various 3D carbonbased nanostructures, including carbon nanotube networks, graphene gels, graphene foams, and 3D CNFs, have been intensively investigated.Over the past few years, there are many reviews summarizing the progress of fabricating 3D carbon-based nanomaterials. For example, Schneider et al. overviewed the recent advance in the synthesis of 3D arranged carbon nanotube architectures. [42] Li et al. reviewed the carbon-based 3D nanostructures for supercapacitors. [36] Cao and Gui et al. comprehensively reviewed the recent progress in synthesis, properties, and energy applications of CNT sponges, aerogels, and hierarchical composites. [43] The development of high-performance electrochemical energy storage devices is critical for addressing energy crises and environmental pollution.

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Ester prodrugs of the phosphinate pseudopeptide N- [(4-deoxy-4-amino-10-methyl)pteroyl] glutamate-γ-[ψP-(O)(OH)]-glutarate (1a) were synthesized. H-phosphinic acids derived from NCbz vinyl glycine esters were converted to the desired pseudopeptides by Michael addition to α-methyleneglutarate esters. Pivaloyloxymethyl (POM) ester moieties were incorporated in both the N-terminal and C-terminal fragments prior to formation of either C-P bond. N-Alkylation of the corresponding amides derived from p-(N-methyl)-aminobenzoic acid with 2,4-diamino-6-(bromomethyl)pteridine gave the target compounds. POM esters of methotrexate and the corresponding γ-glutamyl conjugate were also synthesized using the same strategy. All prodrugs were evaluated in Chinese hamster ovary cells. Although the pseudopeptide prodrugs were ineffective, prodrugs of methotrexate and the corresponding γ-glutamyl conjugate were equipotent with the parent compounds. Stability of the prodrugs was investigated in both phosphate buffer and cell line medium to provide a rationale for the observed biological data.

In this study, galvanic replacement provides a simple route for the synthesis of PdAg hollow nanoflower structures by using the Ag-seeds as sacrificial templates in the presence of l-ascorbic acid (reductant) and CTAC (capping agent). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and EDS mapping were used to characterize the as-prepared PdAg hollow nanoflower catalysts, where they were alloyed nanoflower structures with hollow interiors. By maneuvering the Pd/Ag ratio, we found that the as-prepared Pd Ag hollow nanoflower catalysts had the optimized performance for catalytic activity toward ethanol oxidation reaction. Moreover, these as-prepared PdAg hollow nanoflower catalysts exhibited noticeably higher electrocatalytic activity as compared to pure Pd and commercial Pd/C catalysts due to the alloyed Ag-Pd composition as well as the hollow nanoflower structures. It is anticipated that this work provides a rational design of other architecturally controlled bimetallic nanocrystals for application in fuel cells.

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