In this chapter, we report on catalysis with nanoporous gold (npAu). Beginning with an introduction to the concept of catalysis, we establish the broader background of the research on the surface chemistry and catalysis with npAu. In the following sections, we discuss the interaction of prime reactants such as O2, CO, and alcohols, such as methanol and ethanol, with gold surfaces. We focus on experimental work performed under ultrahigh-vacuum conditions, dealing with single crystals and npAu. Oxygen is discussed first; it is a key reactant that â activatesâ the gold surface for a variety of chemical reactions, such as the oxidation of CO at low temperatures, but also mechanistically more complex reactions, such as the oxidation of alcohols. The following sections concern the latest insights regarding the ambient-pressure catalysis with npAu. We discuss the gas-phase catalysis of npAu with an emphasis on the low-temperature oxidation of CO and alcohols, especially emphasizing the correlation to model experiments under ultrahigh-vacuum conditions, which help to understand the reactions at a molecular level. We will also cover aspects of liquid phase catalysis with npAu, reporting on two exemplary and important reactions. Finally, we treat the surface modification of npAu with metal oxides, this latter subject being an upcoming focus on a specific design of the material for catalytic applications.