Deactivation and regeneration of in situ formed bismuth-promoted platinum catalyst for the selective oxidation of glycerol to dihydroxyacetone
Abstract
Glycerol oxidation over a Pt catalyst can be effectively enhanced by a Bi additive in terms of activity and 1,3-dihydroxyacetone (DHA) selectivity. However, this catalyst system can suffer from serious deactivation. Here, a Bi-promoted Pt catalyst was developed to selectively produce DHA by maintaining the glycerol solution with Bi(NO3)3·5H2O to meet the continuous operation of practical applications. The catalyst deactivation mechanism was investigated in terms of leaching, over-oxidation, agglomeration and poisoning. It was ascertained that the catalyst deactivation was due to the adsorption of chelating intermediates on the catalyst surfaces. A regeneration method by post-heat-treatment at 200–300 °C could remove the intermediates and regenerate the catalyst, allowing recycling for at least 5 runs without clear catalyst deactivation.