This dissertation addressed the applications of nanostructured materials as oxygen carriers (OCs) and catalysts in poly lactic acid (PLA) thermal decomposition. In chapter 1~4, the stability and cyclibility of metal oxides and supported metal oxides as OCs were evaluated in an isothermal fixed bed reactor at different temperatures for 50 cycles with methane as fuel, up to 15h while their structural, physical and chemical properties were identified using XRD, SEM, TEM, BET, XPS and Ar/H2-TPR. In chapter 5, aerosol synthesized Bi2O3 was found to be a useful catalyst in thermal PLA decomposition, which could lower the on-set decomposition temperature by ~75 T. The developed study protocol could be applied to various metal oxides and polymers to study their catalytic thermal decompositions as well.