Hydrothermal synthesis, structure, and electrochemical properties of a three-dimensional vanadium-nickel phosphate (C_2H_(10)N_ 2)_4[H_2Ni(H_2O)_2(VO)_ 8(OH)_4(PO_4)_8]·H_2O

摘要

The three-dimensional vanadium-nickel phosphate (C_2H_ (10)N_ 2)_4[H_2Ni(H_2O)_ 2(VO)_8(OH)_4(PO_4)_8] ·H_2O (1) was prepared by hydrothermal methods and its structure and electrochemical properties were characterized. The compound crystallizes in the monoclinic system with the space group P2_1 and cell parameters a = 14.392(3) ?, b = 10.122(2) ?, c = 18.305(4) ?, β = 90.34(3)°, V = 2666.7(9) ?~3, Z = 2. The structure consists of macroanionic V-Ni-P layers constructed from VO_5 square pyramids, NiO_6 octahedra, and PO_4~ (3-) tetrahedral groups. The layers are further connected into a 3D infinite structure through the NiO_6 octahedra and there are organic species protonated ethanediamine molecules and water molecules located, which make the structure more stable. Its electron sponge behavior was revealed via electrochemical tests.