In the present study, we addressed the palladium (Pd) decoration of multiwalled carbon nanotube (CNT)/activated carbon (AC) hybrid composites (MWCNT/AC), and examined the catalytic behavior of the composites in the hydrogenation of trans-cinnamaldehyde. The MWCNT/AC composites were prepared by growing CNT network on the surface of AC granules, using the chemical vapor deposition method. XPS analysis revealed that the MWCNT/AC and COOH–MWCNT/AC composites and isolated AC adsorbed Pd at different oxidation states when dipped into a Pd microemulsion: isolated AC and the COOH–MWCNT/AC composite adsorbed Pd nanoparticles at di- and tetravalent states (Pd2+/4+), while the MWCNT/AC composite adsorbed Pd nanoparticles at zero and tetravalent states (Pd0/Pd4+). The MWCNT/AC composite may thereby have hierarchical Pd adsorption properties dependent on the MWCNT network type grown onto the AC surface. Regarding the catalytic performance, the (Pd0/4+)-MWCNT/AC catalyst displayed higher selectivity to hydro-cinnamaldehyde formation (95.9%) when compared with the (Pd2+/4+)-AC and (Pd2+/4+)-COOH–MWCNT/AC catalysts (72.1% and 91.4% selectivity, respectively). The catalytic performance of the (Pd0/4+)-MWCNT/AC catalyst with 2.8 wt% of Pd loading was also superior than the catalytic performance of commercial catalysts with 5 and 10 wt% of Pd loading and other Pd/CNTs catalysts reported in the literature.
Biography:
Elaine Matsubara holds a BA (2002) in Chemistry, PhD (2010) in Science from the University of São Paulo (USP), a part of her PhD studies from the Instituto de Ciencias de Los Materiales de Madrid - Spain, Italian National Agency for New Technologies Energy and Sustainable Economic Development, and University of Rome La Sapienza - Italy. She is presently PhD researcher at University of São Paulo (USP), Brazil. Her work focuses on synthesis of doped carbon nanotubes, 3D hybrid hierarchical carbon nanomaterials and graphene for energy devices applications. Her experience is focuses on energy devices and nanocomposites to filtration, catalysis, environmental remediation and polymer reinforcement.
