Significantly suppressing CO release achieved by the catalysis effect of nanostructured rare earth/manganese oxides: Application in flame retardant thermoplastic polyurethane

[Display omitted] •The rare earth Mn-based catalysts effectively improved the fire safety of thermoplastic polyurethane (TPU) composites.•The Mn-La shows the best smoke suppression effect with 41.3% reduction in Ds max.•The rare earth Mn-based catalysts function via catalytic oxidation and promoting carbonization.•DFT calculations illustrate the mechanism of inhibition of flue gas toxicity. There is significant smoke and toxic volatiles generated from the combustion of thermoplastic polyurethane (TPU), which has compromised its application and posed a significant threat to human life. Here, the hydrothermal-citrate complexation method synthesised the rare earth Mn-based composite catalyst and blended with TPU to mitigate smoke release and toxic gas generation during TPU combustion. The results demonstrate that the inclusion of 3 wt% Mn-La and Mn-Ce catalysts into TPU leads to a 41.3% and 33.6% decrease in maximum smoke density (Ds max), respectively, along with a 52.4% and 50.5% reduction in peak CO production rate (pCOPR). The mechanism of rare earth Mn-based catalyst-based smoke suppression and toxicity reduction in TPU is explained at a microscopic scale based on density functional theory (DFT) research: the introduction of catalyst bolsters the adsorption of O2 and CO on the surface of TPU nanocomposites and facilitates the oxidation of CO. Additionally, it can expedite the formation of dense carbon layers and impede heat and mass transfer. The TPU nanocomposites exhibit excellent flame retardancy and effective smoke suppression. A feasible strategy for manufacturing fire-safety TPU nanocomposites with favorable comprehensive properties is proposed.