Significant research has focused on enhancing catalyticperformancethrough solar energy conversion, and the design of photocatalysisincorporating surface plasmons is drawing considerable attention asa highly competitive catalyst system. Although the hot electron processis the primary mechanism in plasmonic photocatalysis, the precisefunction of hot electron transport in catalytic reactions remainsunclear due to the absence of direct measurement. Here, we demonstratethe intrinsic relationship between surface-plasmon-driven hot electronsand catalytic activity during hydrogen oxidation, utilizing catalyticSchottky nanodiodes (Pt/Ag/TiO2) for antenna-reactorplasmonic photocatalysis. The simultaneous and independent measurementsof hot electron flow and catalytic turnover rate show that the plasmoniceffect amplifies the flow of reaction-induced hot electrons (chemicurrent),leading to enhanced catalytic activity. Plasmonic photocatalytic performancecan be controlled with light wavelengths, intensity, surface temperature,and structures. These results elucidate the hot electron flow on photocatalysisand offer improved strategies for efficient catalytic devices.