Investigating Effects of Nanoscale Facets on Surface Photocatalytic Activity in Cubic Gold Nanoparticles

Gold (Au) nanoparticles are effective for harvesting optical energy and are of particular interest because of their potential applications in next-generation catalytic technology. In order to inform future design development, it is crucial to better understand the fundamental processes involved. Here, we present experimental results from the Maloja instrument at SwissFEL where we utilized Coherent Diffraction Imaging (CDI) in coincidence with Velocity Map Imaging (VMI) to establish a relationship between nanoparticle morphology and surface catalytic activity. The 400 nm optical pump, operating near gold’s plasmon resonance, initiates ionization of the nanoparticle. A time-delayed 900 eV X-ray pulse serves as a multi-modal probe, simultaneously capturing structural information with CDI and ionic fragment momenta through VMI. Phase retrieval of diffraction data was implemented to uncover real-space information and to obtain the nanocube orientations. Additionally, an rBasex Abel inversion procedure was used on 2D VMI projections to reconstruct 3D velocity distributions.