Lawrence Berkeley National Laboratory

Design of metal-semiconductor interfaces and heterostructures is of strong interest for various catalytic applications including photocatalysis. In this work, a series of hollow Au nanosphere (HGN)-Cu2O core-shell nanostructures with varying core surface rugosities are synthesized and investigated for possible photocatalytic applications. HGN surface rugosity is tuned by pH modification during galvanic exchange, and carboxyl groups are utilized as coordination sites to deposit uniform Cu2O shells onto the gold surfaces. Final core-shell structures are verified by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD). Information regarding chemical state and electronic band structure is acquired by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Ultrafast transient absorption (TA) reveals that charge separation in bumpy HGN (bHGN)-Cu2O may effectively provide longer-lived photoexcited carriers, offering great potential for utilization in advanced photocatalytic processes.