A novel structure-activity relationship for the aqueous phase reforming of glycerol was established by showing that alterations in the synthesis of 2% Pt/Al2O3 catalysts resulted in a change in the reaction pathway, thereby allowing the reaction to be directed to produce either the formation of liquid phase products, such as hydroxyacetone and 1,2-propanediol, an important chemical in the fine chemicals industry, or gas phase products (H2). Using the colloidal method to synthesise 2% Pt/Al2O3 nanoparticle catalysts allowed fine control over the Pt particle size between 2 to 3.6 nm, with an increase in temperature in the colloidal reduction step producing larger Pt nanoparticles. The conventional techniques of XRD and TEM were complemented by EXAFS analysis to confirm this size trend . On systematically investigating the catalytic performance of the supported Pt nanoparticles in the aqueous reforming of glycerol, it was found that an increase in particle size not only led to a higher conversion, but also selectively changed the reaction pathway to produce a different product distribution, showing a higher yield of liquid products such as 1,2-propanediol. These results show that the conversion of glycerol on Pt catalysts is structural sensitive and a minor change of Pt size significantly affects activity as well as yield. Analysis of the catalysts after reaction along with investigation into the complex reaction network of the APR of glycerol allowed insight into the surface chemistry whereby links could be drawn between specific catalytic sites and differing reaction pathways. It was found that edge sites were responsible for the dehydrogenation of glycerol in the reforming process, producing hydrogen as the main product, whereas crystal sites prominent on large Pt particles led to higher yields of liquid products. These structure-activity relationships and stability of the catalysts will be presented and discussed.

Directed Glycerol reforming through tailored platinum nanoparticles

255th National Meeting (2018)

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