Catalytic Nanoparticles sitting on top of Graphene: The heterojunction interaction with H2 gas followed by in-situ GISAXS Experiment

MARIA CELESTE DALFOVO; CRISTIÁN HUCK IRIART; LISANDRO J. GIOVANETTI; FRANCISCO J. IBAÑEZ

Campinas

Congreso; 27th Annual User Meeting LNLS/CNPEM (RAU); 2017

CNPEM

There is a great interest in better understanding the phenomena that occurs at thenanoscale between metallic/catalytic nanoparticles and hydrogen gas. This hasimplications not only in fundamental aspects but also in some applications such as in hydrogen sensing and catalysis. We chemically synthesize Pd, Pt, andPd/Pt alloy nanoparticles (NPs) protected with organic ligands which are later assembled on graphene(obtained by CVD). The film of NPs is simply formed by incubating graphene in the NPs solution for some time. Once the heterojunction is formed, it is placed in an ad-hocchamber and exposed to alternating flows of pure He and H2 (at 5%) during in-situ GISAXS experiments. First, I will show the differences in NPs assembly when using Si vs. graphene as substrates. I will also show how the film restructures upon the presence of H2 gas and the importance of the metal composition. Finally, I will demonstrate that this heterostructures can be used for detecting H2 at low concentrations and for reducing molecules such as methylene blue