Invited Speaker Abstract: We have used gold nanostructures to excite various plasmonic modes such as multi-scattering, hot electron injection (HEI), plasmon-induced resonant energy transfer (PIRET) and local electromagnetic field (LEMF). Together they enable to enhance the utilization of solar light for photocatalytic processes. Detailed experimental and mechanism studies have been conducted to examine the plasmonic enhancement in photocurrent, photodegradation and total water splitting. Our work may find potential applications in optical redox-based sensors and green energy.