Controlled synthesis of carbon nanomaterials with particular shape, composition, architecture, and doping is very important, yet still a great challenge, for enhancing supercapacitor performance with high energy and power densities and long lifetime. Herein, we demonstrate an interesting process combining surfactantless and templateless wet chemical and post-high-temperature carbonization strategies for obtaining a new class of nitrogen-doped hierarchical porous carbon nanowhisker ensembles supported on carbon nanofibers (NHCNs) with tunable micropores and a nitrogen-doping level for high-performance supercapacitors. Under the optimal pore size and nitrogen doping controlled by carbonization at different temperatures, the NHCNs (NHCNs-750) carbonized at 750 °C shows an optimal specific capacitance of 210.1 F g −1 at 5 mV s −1 , which is much higher than other onedimensional carbon nanostructures (e.g., pure carbon nanofibers (2.6 F g −1 ) and carbon nanotubes (10.6 F g −1 ) at 5 mVs −1 ). NHCNs-750 also showed good rate capability of 78.5% and 75.2% capacitance retention at 100 mV s −1 and 200 mV s −1 , respectively, and excellent cycling stability of 96.2% capacitance retention after 3000 cycles. Furthermore, we found that the specific capacitance of NHCNs can be further increased to 254.3 F g −1 by a KOH-assisted high-temperature process. The present work opens a new route to design advanced 1D hierarchical carbon nanomaterials with tunable pores and nitrogen doping for enhancing energy storage and conversion applications.

The 1,1-diphenyl-2-picrydydrazyl (DPPH) assay on the extract of Phyllanthus urinaria L. (Euphorbiaceae) displayed considerable radical-scavenging activity (SC50 = 14.3 microg/ml). Further bioassay-guided purification of the extract led to the isolation of a series of 15 phenolic compounds, including the ellagitannins 1-7, the flavonoids 8-10, and the simple hydroxylated (or glycosylated) aromatic acids 11-15. Their structures were identified by spectroscopic analyses and comparison with authentic samples or literature data. The structure of repandinin B (1) was for the first time fully assigned by 1D- and 2D-NMR experiments. The phenolic compounds 1, 3, 4, 6, 9, 11, and 15 have not been isolated before from the title plant. The antioxidant activities and mushroom-tyrosinase-inhibitory activities of all compounds were determined by DPPH-radical-scavenging and mushroom-tyrosinase-inhibitory assays (Table 2).

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