Bridging photocatalysis and plasmonics: the dual role of interband and intraband transitions

The flourishing field of plasmonic photocatalysis promises to break the efficiency bottleneck of traditional semiconductors by harnessing hot carriers from metals. A long-standing narrative often simplistically contrasts plasmonic intraband hot carriers with their interband counterparts. This feature article review advocates for a paradigm shift by proposing that interband and intraband transitions are not competing pathways, but rather synergistic actors playing a complementary dual role. Together, they enable a versatile and broadened strategy for driving diverse chemical transformations. We examine this cooperative behavior through the strategic engineering of electronic structures in tunable nanomaterials such as alloys and heterostructures, and highlight how in situ spectroscopic techniques reveal the distinct functions of each transition pathway. Looking forward, we discuss design principles for next-generation photocatalysts in which the dual role can be precisely optimized to enhance both efficiency and selectivity.