Preparation of Novel Oxygen Carriers Supported by Ti, Zr-Shelled γ-Alumina for Chemical Looping Combustion of Methane

Journal article, 2020

Highly stabilized mesoporous core-shell-structured oxygen carriers (OCs) were fabricated by a repetitive coating process of alumina supports using the mesopore-forming surfactant assembly method. The wet coating strategy, along with the sol-gel process, was used for the synthesis of mesoporous material-shelled OCs with various shell compositions (i.e., zirconia, titania). The cyclic performance of the synthesized OCs during chemical looping combustion (CLC) was investigated in a thermogravimetric analyzer (TGA). The mesoporous-shelled OCs demonstrated significantly better performance compared to the OCs without mesoporous shells. The synthesized OCs with a mesoporous zirconia/titania shell reveal a unique oxygen capacity of 100% based on active metal oxide for supported NiO and Fe2O3. Also, the synthesized OCs showed no activity loss after 10 cycles. This was attributed to the exceptional core-shell coating strategy, in which the thermally stable mesoporous Zr/Ti layers prevent the sintering and over-reaction of the active metal oxide crystals with the alumina support.