Preparation and Structural Characterization of Platinum Nanosheets Intercalated between Graphite Powder with High Surface Area

Abstract

Synthesis of platinum nanoparticles intercalated between layers of commercially available graphite powder samples possessing surface area values ranging from 20 to 750 m2 g-1 was attempted by the insertion of platinum chloride between the layers followed by hydrogen reduction. Platinum nanosheets with 1-4 nm thickness and 5-300 nm width and hexagonal holes were obtained for the graphite powder with 20 m2 g-1 independent of the platinum loadings (5, 10, and 15 wt%). Platinum nanosheets with the similar size (1-4 nm thickness and 5-300 nm width) and hexagonal holes were formed for graphite powder with 120 and 300 m2 g-1 with only 15 wt% platinum loading, but not for 5 and 10 wt% platinum loadings. Interestingly, for the graphite powder with higher surface area of 500 and 750 m2 g-1, platinum nanosheets were not formed. Platinum nanosheets intercalated between graphite samples were evaluated for cinnamaldehyde hydrogenation in supercritical carbon dioxide solvent. High cinnamyl alcohol selectivity was obtained for the platinum nanosheets intercalated between graphite layers having surface area of 20 m2 g-1; however, hydrocinnamaldehyde selectivity was high for the platinum nanosheets intercalated between graphite samples having surface area of 120 m2 g-1.