Abstract
Photocatalytic overall water splitting (OWS) is a promising approach for hydrogen production, leveraging solar energy to convert water into hydrogen and oxygen efficiently. However, the efficiency of current photocatalytic systems remains significantly below theoretical limits due to intrinsic constraints of semiconductor-based materials. Plasmonic metal-semiconductor photocatalysts represent a transformative solution by utilizing localized surface plasmon resonance (LSPR) to enhance light harvesting and promote hot electron transfer, effectively addressing these limitations. This study highlights the role of ultrafast spectroscopic techniques in revealing the temporal and spatial dynamics underlying plasmonic enhancement. These insights uncover key energy transfer pathways and interfacial charge processes that are critical for improving photocatalytic performance. By integrating recent experimental evidence with emerging design strategies, we outline key principles for the rational development of next-generation photocatalysts. This work aims to advance the overall efficiency of OWS systems, paving the way for more effective solar-driven hydrogen production technologies.