Hexamethylenetetramine Directed Synthesis and Properties of a New Family of α-Nickel Hydroxide Organic−Inorganic Hybrid Materials with High Chemical Stability

Abstract

A new family of organic-inorganic hybrid material of alpha-nickel hydroxide formulated as Ni(OH)2-x(An-)x/n-(C6H12N4)y.zH2O (A=Cl-, CH3COO-, SO4(2-), NO3-; x=0.05-0.18, y=0.09-0.11, z=0.36-0.43) with high stability and adjustable interlayer spacing ranging from 7.21 to 15.12 A has been successfully prepared by a simple hydrothermal method. The effects of various anions and hexamethylenetetramine (HMT) on the d values of alpha-nickel hydroxide have been systematically investigated. This family of hybrid materials is of such high stability that they can stand more than 40 days in 6 M KOH. The product with a formula Ni(OH)1.95(C6H12N4)0.11(Cl-)0.05(H2O)0.36 has a high surface area of about 299.26 m2/g and an average pore diameter of about 45.1 A. The coercivity (Hc) value is ca. 2000 Oe for the sample with a d spacing of 13.14 A. Moreover, the prepared alpha-Ni(OH)2 in our experiment is of high stability in strong alkali solution. Such high stability could be derived from strong chelating interactions between the Ni ions and HMT molecules with the interlayers. This high chemical stability could make this material more suitable for the applications.

Controllable Synthesis of VSB‐5 Microspheres and Microrods: Growth Mechanism and Selective Hydrogenation Catalysis

“…After 3 h, the product consisted of disperse VSB-5 rods and numerous flowerlike microspheres assembled from thin films, which could be identified as a-Ni(OH) 2 (Figure 2 C). [21] The images in Figure 2 D and E suggest that the preformed a-Ni(OH) 2 acted as a sacrificial template for the formation of VSB-5 microspheres. On further reaction, more and more VSB-5 wires were observed in the product, and microspheres assembled from wires gradually formed (Figure 2 G).…”

“…[21] The growth process of these structures in the closed autoclave was carefully monitored by time-dependent experiments. The XRD patterns in Figure 1 and FESEM images in Figure 2 clearly reflect the transformation process of the microspheres.…”

“…, and undecomposed HMT react together to form a-Ni(OH) 2 hybrid inorganic-organic composites. [21] As the reaction proceeds, the amount of PO 4 3À and HPO 4 2À increases gradually. Since the thin films with thickness of about 15-50 nm assembled into spinous a-Ni(OH) 2 flowers, the surface energy is higher here than elsewhere because of the slender diameter.…”

Ultrasound-assisted hexamethylenetetramine decomposition for the synthesis of alpha nickel hydroxide intercalated with different anions

“…Above 3000 cm −1 , the broad structure belongs to the hydrogen bonded O-H stretching of intercalated water, as well as the hydroxide. The sharp band at 3633 cm −1 is due to the free O-H stretching most likely from a hydroxide group not interacting with water molecules [8][9][10]. All the hydroxide samples, except for the sulfate-intercalated product, show very strong free O-H stretching peak.…”

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

“…There exist four polymorphs for Ni(OH) 2 : aNi(OH) 2 , b-Ni(OH) 2 , b-NiOOH and c-NiOOH [6]. So far, Ni(OH) 2 has been synthesized successfully with different morphology, including Ni(OH) 2 hollow microspheres [7], b-Ni(OH) 2 flowers [8], and a-Ni(OH) 2 organic-inorganic materials [9,10]. The morphology and size of Ni(OH) 2 have significantly influence on their properties, applications and electro-chemical performance [11][12][13][14][15].…”