Precursor control of the inversion degree of magnesium-cobalt spinels

Preparation of layered double hydroxides and their applications as additives in polymers, as precursors to magnetic materials and in biology and medicine

“…77 In an idealized topotactic transformation, the metal ions in the LDH layers undergo a diffusionless transformation to the spinel phase, in which one third of the metal ions change their octahedral coordination to tetrahedral with retention of their original statistical distribution. 74,82,83 In this case the spinel derived from the LDH precursor with Mg:(Fe II + Fe III ) = 0. Furthermore the fact that the spinel is produced from a single solid precursor rather than a mixture of two or more precursors means that the calcination process requires a much shorter time, leading to a lower chance of side-reactions occurring.…”

Catalytic decomposition of N2O over Ni and Mg-magnetite catalysts

“…These two material parameters in turn depend heavily on the synthetic approach and post synthesis treatment of the precursor compounds. [13][14][15][16][17] Hong He's group also reported that the introduction of CeO 2 into the Co 3 O 4 spinel could promote the catalytic activity. 18 Moreover, it is well known that cobalt-based catalysts present excellent catalytic activities for N 2 O decomposition.…”

“…11,12 It is known that the synthetic process of spinel precursor compounds, which determines final oxide structure, texture, and chemical composition, plays a crucial role in ultimate performance of these spinels. 13,14 Spinel oxides belong to a class of complex oxides with the chemical formula of AB 2 O 4 , in which A ions are generally divalent cations occupying tetrahedral sites and B ions are trivalent cations in octahedral sites. The cobalt oxide spinel Co 3 O 4 , for example, is one receiving considerable interest.…”

“…15,16 The A component of the spinel oxide Co 3 O 4 is often substituted partially with other divalent 3d transition metals, Cr, Mn, Ni, Cu, Zn, and earth alkali metals such as Mg, to create special physicochemical properties for a specific application. [11][12][13][14] With regard to their applications in catalysis, for example, it has been known that the catalytic activity of these spinels depends essentially on two factors: the degree of A substitution and the degree of inversion of the spinel. These two material parameters in turn depend heavily on the synthetic approach and post synthesis treatment of the precursor compounds.…”

Modeling and optimization of synthesis condition of CuCr2O4 Spinel for CO oxidation

“…These metals are environmentally friendly [16][17][18][19]. Catalyst design is a complex process involving many steps and variables as well as complex interactions among these variables, which make the experimental studies quite expensive and time-consuming [20,21].…”