Nanometer-Sized MoS2 Clusters on Graphene Flakes for Catalytic Formic Acid Decomposition

MoS 2 was deposited on graphene flakes via decomposition of MoS 3 in vacuum at different temperatures (500–800 °C). The materials obtained were tested for catalytic formic acid decomposition, giving mainly hydrogen and carbon dioxide. According to atom-resolved transmission electron microscopy study, a considerable amount of MoS 2 clusters with a mean size of 1 nm was formed on the graphene surface at 500 °C. Simulation of the structure of a cluster revealed the presence of Mo-edge atoms. Raising the preparation temperature up to 800 °C led to agglomeration of MoS 2 clusters and formation of thin crystalline MoS 2 particles 20–30 nm in size. The sample enriched with the MoS 2 clusters showed 6 times higher catalytic activity at 160 °C than the sample with the crystalline MoS 2 particles. This demonstrates that the observed nanometer-sized MoS 2 clusters are responsible for catalysis.