Graphene: Applications in Surface Science Studies

• This thesis addresses how graphene can be a valuable asset for surface science studies. Using a combination of X- ray photoelectron spectroscopy, scanning tunneling microscopy, and low-energy electron diffraction, we take advantage of graphene’s sensitivity to changes in its chemical environment to obtain an atomic scale understanding of different reactions occurring above and below the film.As a substrate, graphene provides an inert base for studying growth mechanisms. Specifically, we use it to investigate the electron-induced dissociation of borazine, a common precursor for Boron Nitride deposition. Thanks to the inert character of graphene, we can discern the dissociation due to the interaction with the electron beam from any surface- induced dissociation processes. Moreover, graphene can be used as an adsorption template for studying reactions between adsorbates and gas phase molecules. Using hydrogen adsorbates, we analyze the stability of different H- structures under mbar pressures of oxygen. We show that graphene acts as a catalyst for water formation by providing the required adsorption configuration that promotes the reaction. This finding paves the way for future research using graphene as an adsorption template for fundamental catalysis studies.Graphene can also be employed as a confining agent to study undercover reactions, a trending topic in the catalysis field due to the reported higher performance of catalysts when placed in confined environments. We use graphene to investigate copper oxidation undercover, revealing that its presence stabilizes a Cu2O phase undercover, delaying the evolution toward complete oxidation (CuO). Graphene is also an ideal model system for studying more fundamental aspects of undercover reactions, such as the coexistence of different molecules undercover or their intercalation kinetics. Specifically, we use graphene to investigate the coexistence of hydrogen and CO with already intercalated oxygen while following the intercalation process in situ with APXPS.Altogether this thesis provides several examples of how graphene can be integrated into surface science studies and paves the way for its implementation in the surface science field.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Keyword

Graphene

Surface Science

EBID

Catalysis

undercover catalysis

XPS

APXPS

STM

Publication and Content Type

dok (subject category)

vet (subject category)