Catalytic performance promoted on Pt-based diesel oxidation catalyst assisted by polyvinyl alcohol

Eliminating vehicle emission is of importance due to the severe limit value. The work reports a convenient strategy of improving dispersion of platinum-based catalyst with the assistance of polyvinyl alcohol in a varied addition amount. Following the "two-step" annealing techniques, the catalytic performance of the polymer-assisted catalysts in diesel was obviously enhanced because of the improved dispersion of the platinum. Based on experimental results, the long chains of polymer resulting in the steric effect are presumed to isolate platinum ion, inhibiting the aggregation of platinum particles and then improving its dispersion. And the hydroxyl bonding between the polymers could convey electron to platinum species, leading to the lower platinum valence state. Both effects are positive resulting in an excellent NO maximum conversion of around 65% at the optimal introduction of 5 mass% of polymer, as the diesel oxidation catalyst (DOC), which could be inclined to a good purification in the diesel aftertreatment. Hopefully, the convenient research method could initiate the exploration and application of polymer-assisted catalysts for well-dispersed noble metal nanoparticles in eliminating exhaust emission.