| dc.description.abstract | To increase the solubility of graphene in water, we modified the graphene skeleton with sulfonyl groups. With hydrazine as the reducing agent, SB12 as the surfactant in the aqueous phase, platinum and palladium nanoparticles were produced on the graphene plane skeletons, separating the graphene layers. Sample 1 has 56 wt% Pt, with average of metal particle size of 83.2 nm; sample 2 has 14 wt% Pt, with particle size of 27.3 nm; sample 3 has 32 wt% Pd, with particle size of 2.4 nm, and sample 4 has 16 wt% Pd, with particle size of 8.9 nm.
Towards hydrogen storage applications, sample 3 performs the best. Under 510 psi hydrogen pressure, the hydrogen uptake reaches 2.19 wt%. The samples 1~4, when used in catalytic hydrogenation of styrene, all gave better than results commercial catalysts. For samples 1、2, they are better than the commercial Pt / C; and for samples 3、4, they are better than the commercial Pd / C.
Ionic liquid [HOCH2CH2NH3][HCO2] was used as a solvent, as a reducing agent, and also as a surfactant, converting Pt metal source to Pt nanoparticles under microwave heating conduction. Following are the characteristics of Pt nanoparticles formed on the plane of graphite oxide and graphene. Sample 5 is on the graphene substrate, with Pt 62 wt%, and the average metal particle size of 5.0 nm, sample 7 on the graphite oxide substrate, with Pt 40 wt%, and the average metal particle size of 18.8 nm, and sample 8 on the graphite oxide substrate, containing Pt 1 wt%, and the average metal particle size of 4.7 nm. Samples 5, 7~8 were seen to have a very special cubic shape. Pt nanoparticles in sample 6 on the graphene substrate, with Pt 13 wt%, and the average metal particle size of 14.6 nm were in multiply truncated cubic shape. The rationale is that the ratio between the concentration of reducing agent and that of metal source is too large under the reaction condition, and the formation and the stacking of metal become too fast to grow to crystals properly in a cubic shape. Sample 8 still formed a cubic shaped nanoparticles, presumably that graphite oxide is rich with the oxygen functionalities which regulate the seeding and growth of the Pt nanoparticles in proximity.
Sample 5 and 6 were used in the catalytic hydrogenation of styrene. Better results were obtained for 5 and 6 when compared with that of commercial Pt / C.
| en_US |