Fabrication of Novel Hierarchical β-Ni(OH)₂ and NiO Microspheres via an Easy Hydrothermal Process

Abstract

Hierarchical β-Ni(OH)2 microspheres with 6−8 μm diameter assembled from nanoplate/nanosheet building blocks were successfully fabricated via a hydrothermal process in the presence of an anion surfactant poly(ethylene glycol) 4-nonylphenyl 3-sulfopropylether potassium salt. The factors influencing the formation of hierarchical Ni(OH)2 microspheres were monitored by using SEM characterizations. The effect of hydrothermal growth temperature on the Ni(OH)2 morphology was also investigated. NiO microspheres assembled from nanoplate/nanosheet were also obtained by thermal decomposition of the as-synthesized β-Ni(OH)2 at 320 °C for 3 h in air. HRTEM and SAED results reveal that the Ni(OH)2 and NiO nanosheets are single crystalline. Nitrogen adsorption−desorption measurements of the BET surface area and pore size of NiO microspheres were 160 m2/g and 30−50 nm, respectively. It is anticipated that these novel hierarchical microsphere structures of Ni(OH)2 and NiO will have great applications in Ni-based batteries, catalysis, and other potentials.