A Pickering Emulsion of Bifunctional Interface Prepared by Pd Nanoparticles Supported on Silicane-Modified Graphene Oxide: An Efficient Catalyst for Water-Mediated Catalytic Hydrogenation
A Pickering emulsion was prepared by Pd Nanoparticles Supported on organic-silicane-modified graphene oxide (GO-Si )， which was used as highly efficient catalyst for selective hydrogenation of cinnamaldehyde (CAL) in water medium in place of organic solvents. GO modified by silicane enhanced the lipophilicity on its surface, thus promoting adsorption of CAL on the interface of Pickering emulsion prepared by Pd/GO-Si. In addition, lipophilic surface of Pd/GO-Si was beneficial to stabilize the Pickering emulsion of water in oil (W/O). It was found that as the grafting amount of silicane increased from 0.6 to 1.4g, droplets in Pickering emulsion of W/O became smaller and denser, which was closely related to catalytic performance for selective hydrogenation of CAL in water medium. As-prepared Pickering emulsion exhibited high activity and selectivity for hydrogenation of CAL , which was attributed to the bifunction-synergy of the interface of Pickering emulsion prepared by Pd/GO-Si. Furthermore, compared with the conventional catalytic systems proceeding under organic solvents, the Pickering emulsion prepared by Pd/GO-Si exhibited superior activity under the same reaction conditions. The maximum yield of hydrocinnamaldehyde (HCAL) was 83% in 20 min. Moreover, the catalyst demonstrated good recyclability and versatility for the selective hydrogenation with various substrates.