Hierarchical flower-like Ni–Co layered double hydroxide nanostructures: synthesis and super performance
Three-dimensional hierarchical flower-like Ni–Co layered double hydroxide (LDH) nanostructures composed of porous nanosheets were prepared from Ni–Co precursors under optimized preparation conditions towards applications in energy storage and adsorption. Ni–Co LDHs were formed via an olation reaction and subsequent growth to nanosheet structures. It is found that suitable Ni/Co ratios for precursors resulted in Ni–Co LDHs with a large specific surface area, porous structure and expanded interlayer spacing, which contributed to the improvement in performance for electrochemistry and anionic dye adsorption. In the case of a Ni/Co molar ratio of 1, the Ni–Co LDHs as a sorbent for removing anionic dyes (acid fuchsin and Congo red) in water revealed a high adsorption rate, large adsorption capacity and good recycling performance. Using a molar ratio of Ni/Co of 0.5, the specific capacitance of the as-prepared electrode reached 3168.3 F g−1 at a current density of 1 A g−1 and a large capacitance retention of 90.5% after 3000 cycles at high current density. The Ni–Co LDHs possess enormous application potential as a multifunctional material for supercapacitors and dye adsorption.