Polymorphous α- and β-Ni(OH)2 complex architectures: morphological and phasal evolution mechanisms and enhanced catalytic activity as non-enzymatic glucose sensors

Abstract

The morphological modulation and phase conversion of a-and b-Ni(OH) 2 complex architectures with varying subunits from nanopetals, nanocolumns, nanocones, and nanoflakes were investigated using a facile coordination homogeneous precipitation method in the Ni(NO 3 ) 2 + urea system. Slow growth and nucleation rates due to relatively low reaction temperatures and molar ratios of CO(NH 2 ) 2 to Ni(NO 3 ) 2 induced the formation of uniform flower-like a-Ni(OH) 2 architectures. Such flower-like architectures originated from subordinate nanopetals that grow perpendicular to the primordial nanopetal surface and are driven by minimum surface free energy effects. At relatively high reaction temperatures, flower-like a-Ni(OH) 2 can transform into b-Ni(OH) 2 microspheres assembled from nanocolumns, nanocones, and even nanoflakes by varying the reaction time. These processes could be related to the synergetic effect of the anisotropic growth and continuous increase in mass transportation along the [001] direction. Flower-like a-Ni(OH) 2 exhibited better electrochemical activity for glucose oxidation compared with b-Ni(OH) 2 microspheres consisting of nanocones because of its special flower-like morphology with high specific surface areas, well-ordered pores, and layered structures intercalated by water and anions. The approach in this study can be used to fabricate other metal hydroxide nanostructures. Flower-like Ni(OH) 2 nanoarchitectures have potential applications in rechargeable batteries, photonic catalysis, and non-enzymatic sensors for glucose.

Structural, optical and photocatalytic applications of biosynthesized NiO nanocrystals

“…The band at 1643 cm −1 is assigned to bending vibrations of the interlayer water molecules (38,39). The weak band at 2380 and 994 cm −1 are attributed to intercalated CO 2− 3 and NO − 3 (40,41). The presence of 1390 cm −1 arises from the interaction of the samples with the KBr in the pellet (42).…”

Phase and Shape Dependent Non-enzymatic Glucose Sensing Properties of Nickel Molybdate

“…The nanoshphere are distinctly visible with uniform morphology and precise size (as shown in Figure S1). Due to the presence of nanosheets with self‐assembled structure, the surface to volume ratio of the material is expected to be high and it contains large number of surface active sites which can provide very short diffusion pathways for ions and glucose molecules leading to the enhanced electrochemical properties suitable for glucose sensing applications . The elemental distributions of Ni, Mo, and O elements in the NiMoO 4 were also measured using a SEM equipped with EDS and elemental mapping, as shown in Figure (c) and (d).…”

Constructing Patch‐Ni‐Shelled Pt@Ni Nanoparticles within Confined Nanoreactors for Catalytic Oxidation of Insoluble Polysulfides in Li‐S Batteries

“…The solution that was obtained was heated at 160 °C for 30 min in a microwave reactor. After cooling to room temperature, the precipitate was washed several times with deionized water and dried at 60 °C …”