Designing new photocatalytic materials for improving photoconversion efficiency is a promising route to alleviate the steadily worsening environmental issues and energy crisis. Despite the invention of a large number of catalytic materials with well-defined structures, their overall efficiency in photocatalysis is still quite limited as the three key steps light harvesting, charge generation and separation, and charge transfer to surface for redox reactions have not been substantially improved. To improve each step in the complex process, there is a major trend to develop materials based on inorganic hybrid structures. In this case, interface engineering holds the promise for boosting the overall efficiency, given the key roles of interface structures in charge and energy transfer. In this talk, I will demonstrate several different approaches to designing inorganic hybrid structures with improved photocatalytic performance via interface engineering. The typical demonstrations include semiconductor-plasmonics systems for broad-spectrum light harvesting, metal-semiconductor interfaces for improved charge separation, semiconductor-MOF (metal-organic framework) configurations for activated surface reactions. It is anticipated that this series of works open a new window to rationally designing inorganic hybrid materials for photo-induced applications.
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Mastery over the surface of a nanocrystal enables control of its properties in molecular adsorption and activation, and enhances its usefulness for catalytic applications. On the other hand, hybrid systems based on semiconductors and noble metals may exhibit improved performance in photocatalysis such as water splitting, mainly determined by the efficiency in generating carriers. In the systems, perfect interface is certainly the key to efficient carrier separation and transport. Taken together, the surface and interface modulation holds the key to materials design for photocatalytic applications. Here, we will demonstrate several different approaches to designing nanocrystal-based systems with improved photocatalytic performance. For instance, a semiconductor-metal-graphene design has been implemented to efficiently extract photoexcited electrons through the graphene nanosheets, separating electron-hole pairs. Ultrafast spectroscopy characterizations exclusively demonstrate that the charge recombination occurring at interfacial defects can be substantially avoided, enabling superior efficiency in water splitting. It is anticipated that this series of works open a new window to rationally designing hybrid systems for photo-induced applications.