Metallic alloy nanoparticles (NPs) constitute promising materials in the field of heterogeneous catalysis. As compared with bulk pure materials, these NPs take the advantage of potential tuning of their catalytic properties by size and synergetic effects. This is for example the case of Au-Cu NPs which display higher reactivity and selectivity than the pure metals for CO oxidation or for the PROX reaction.
Combining several operando techniques opens up the possibility of determining the structure of the bimetallic NPs from their nucleation up to their exposure to reactive gases. In this talk, I will present Grazing Incidence X-Ray Diffraction (GIXD), Photoelectron Spectroscopy (XPS), and Scanning Tunneling Microscopy (STM) results obtained on Au, Cu and Au-Cu NPs grown on TiO2(110) and exposed to CO and O2.
I will show that combining these experimental methods allows us to determine nucleation sites and epitaxial relationship, study core-shell or alloy formation, stability under gas exposure, effects of thermal treatments and reaction-induced reorientation or recrystallization of NPs.