Shining photocatalysis by gold-based nanomaterials

As an environmentally friendly technology, photocatalysis has been widely used in many fields. Currently, the drawbacks of pristine semiconductors as traditional photocatalysts include poor light harvesting, rapid recombination of charge carriers, and insufficient active surface centers, which largely limit their photocatalytic performance. These technical issues can be well addressed by decorating gold (Au) nanomaterials, including large Au nanoparticles (NPs, >3 nm) and ultrasmall Au nanoclusters (NCs, <3 nm). This Review first briefly introduces photocatalysis by deciphering the photocatalytic process into three consecutive steps: (I) light absorption, (II) charge separation/migration, and (III) surface reactions, with an emphasis on key limitations of each step. Afterwards, we briefly discuss the main synthetic strategies of Au nanomaterials-modified semiconductor photocatalysts (Au-modified photocatalysts for short), and explain how Au nanomaterials can address the above-mentioned technical issues in each photocatalytic step. Subsequently, we highlight several advanced characterization techniques for photocatalysis, which would be useful for elucidating the photocatalytic mechanisms. Finally, we exemplify the applications of Au-modified photocatalysts in energy conversion, environmental remediation, and organic chemistry. This review concludes with a summary and our perspectives on the design and development of high-performance metal-modified photocatalysts in various application fields.