Catalysis on Insulating Substrates*

Molybdenum Disulfide (MoS₂) is one of the most commonly used commercial hydrodesulfurization (HDS) catalysts, but a microscopic understanding of the active sites and reaction mechanisms has been difficult to develop. Understanding these reactions on an atomic scale provide guidance to catalyst design. Improving HDS catalyst design will also rely on our knowledge of the catalyst on industrially relevant, insulating substrates. We will present data from scanning tunneling microscopy and non-contact atomic force microscopy on exfoliated MoS₂ flakes on a silicon dioxide substrate. To determine active sites for HDS, we introduce thiophene molecules that adsorb to the MoS₂. This system provides the first opportunities for atomic scale catalysis studies on industrially-relevant substrates.