Hierarchical NiOx nanotube arrays/CoP nanosheets heterostructure enables robust alkaline hydrogen evolution reaction.

Rational design of low-cost and high-efficiency electrocatalysts for hydrogen evolution reaction (HER) is critical for scalable and sustainable hydrogen production from economical water-alkali splitting. Herein, density functional theory (DFT) calculations reveal that coupling NiOx and CoP could effectively boost overall HER kinetics through lowing the H2O dissociation barrier, accelerating the OH* transfer process, and providing the rapid H* migration kinetics as well as the appropriate H* energetics. Based on these findings, we successfully prepared a three-dimensional (3D) self-supported electrode of ultrathin CoP nanosheets directly grown on the surface-oxidized Ni nanotube arrays via a simple and scalable electrochemical synthesis method. As expected, such a heterostructure electrode exhibits superior alkaline HER performance with low overpotentials of 51 and 164 mV to drive the current densities of 10 and 500 mA cm-2, respectively, outperforming most of the efficient alkaline HER electrocatalysts.

Chemical constituents from Achyranthis Bidentata and their effects on cells proliferation / 中成药

AIM To study chemical constitutes from Achyranthis bidentata Bl.and their effects on cells proliferation.METHODS The aqueous extract from dregs of a decoction of A.bidentata was isolated and purified by Diaion HP-20,Sephadex LH-20,ODS,silica and HPLC colum,then the structures of obtained compounds were identified by physicochemical properties and spectral data.The effects on proliferation of endothelial cells were evaluated by MTT.RESULTS Ten compounds were isolated and identified as cynarasaponin A (1),ginsenoside R0 (2),chikusetsusaponin Ⅳ a (3),chikusetsusaponin Ⅳ a methyl ester (4),chikusetsusaponin Ⅳ a ethylester (5),chikusetsusaponin Ⅳ a butyl ester (6),chikusetsusaponin-1 (7),zingibroside R1 (8),3-O-β-D-glucuronic acid glycosides-oleanolic acid (9),3-O-β-D-glucuronic acid glycosides ethylester-oleanolic acid (10).Compounds 1,6,7,8 exhibited obviously inhibiting effects on HUVEC proliferation.CONCLUSION Compounds 1 and 10 are isolated from A.bidentata for the first time;compounds 1,6,7,8 have strong inhibiting effects on cells proliferation.