L-proline assisted synthesis of flower-like microspheres and triangular nanosheets of β-Ni(OH)₂ and NiO

β-Ni(OH)₂ flower-like microspheres and triangular nanosheets have been hydrothermally synthesized at 180 °C in the presence of L-proline using NH₃ · H₂O and NaOH, respectively, as the precipitant. XRD patterns show that the as-prepared β-Ni(OH) ₂ products are hexagonal phase. TEM and FESEM images indicate that the flower-like microspheres with diameter of 1 ∼ 2 μm are assembled from triangular nanosheets with thickness of 15 nm and edge length of 110 nm. NiO flower-like microspheres and triangular nanosheets can be obtained by calcining the β-Ni(OH)₂ precursors at 350 °C for 2 h in air.