Thermal Decomposition of Solid Metal Oxides

Abstract

The theory of Levin, Bass and Bennemann for the spin susceptibility of transition metal alloys is generalized to describe the properties of liquid metal alloys. The short range structural order in the liquid alloy is taken into account using a lattice theory with the lattice chosen to match the experimentally measured short range behaviour of the liquids. The theory is applied to the alloy systems Au-Ni and Au-Fe and the results are compared to experimental measurements on these systems,and found to give good agreement.

Solar electricity via an Air Brayton cycle with an integrated two-step thermochemical cycle for heat storage based on Co3O4/CoO redox reactions II: Kinetic analyses

“…The k's are strongly dependent on temperature and exponentially increase with increasing temperature. The apparent activation energy is similar in magnitude to the enthalpy change of reaction, consistent with observations about metal oxide thermolysis (Malinin and Tolmachev, 1975). The value is also consistent with the observation that self-diffusion activation energies in spinels are typically 250-350 kJ mol À1 (Oshcherin, 1975).…”

“…The rate limiting mechanism for Co 3 O 4 thermolysis was related to random nucleation where imperfections in surface of the solid reactant material minimize the activation energy (Khawam and Flanagan, 2006). Nucleation has been proposed as the mechanism for several decomposition reactions (Malinin and Tolmachev, 1975;Hutchings et al, 2006;Khawam and Flanagan, 2006;Wong, 2011). A pressure dependence power rate law was included to account for the 3CoO + øO 2 ?…”

Low Effective Activation Energies for Oxygen Release from Metal Oxides: Evidence for Mass‐Transfer Limits at High Heating Rates

“…Chadda et al reported an activation energy for CuO decomposition in air at low heating rate of~313 kJ mol À1 . [27] Later, Malecki et al reported a E a value of~153 and 164 kJ mol À1 for Co 3 O 4 powder and single crystal in a partial vacuum (oxygen partial pressurẽ 0.67 Pa). [27] For Co 3 O 4 decomposition, the activation energy was reported to be ~293 kJ mol À1 in argon.…”

“…carbon, hydrogen), [22][23][24][25] there are some values of activation energies for direct metal oxide decomposition at low heating rates that have been published. [27] For Co 3 O 4 decomposition, the activation energy was reported to be ~293 kJ mol À1 in argon. [26] A value of~238 kJ mol À1 was reported for CuO decomposition in argon.…”

“…Ag 2 O!Ag). The generally accepted scheme for the type 1 decomposition is: [27,39] 1Þ O 2À ðlatticeÞ ! The reaction Fe 2 O 3 !Fe 3 O 4 has also been found to produce both oxygen atoms and molecules.…”