Controlled hydrothermal synthesis of ball-flower Ni(OH) 2 /NiOOH composites assisted by rosin-based betaine zwitterionic surfactant

The ball-flower Ni(OH) 2 /NiOOH composites were successfully synthesized via a facile hydrothermal method, using nickel sulfate as precursor and urea as precipitant, and the rosin-based betaine zwitterionic surfactant as annexing agent. The optimum condition of preparing ball-flower Ni(OH) 2 /NiOOH composites was 10 g/L rosin-based betaine zwitterionic surfactant, at 180 °C for 8 h. The ball-flower Ni(OH) 2 /NiOOH composites were consisted of nanosheets. X-ray diffraction, Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, and surface tension were used to characterize the as-prepared samples. The effect of rosin-based betaine zwitterionic surfactant on the morphology and size of ball-flower Ni(OH) 2 /NiOOH composites were investigated in details. Moreover, a possible formation mechanism was proposed based on the effect of the rosin-based betaine surfactant. The result revealed that the crystallinity of the ball-flower Ni(OH) 2 /NiOOH composites were improved by the rosin-based betaine surfactant, and the morphology and size of Ni(OH) 2 /NiOOH composites could be well controlled in the presence of the rosin-based betaine zwitterionic surfactant.