The significant increase in marine Synechococcus abundance following dust deposition cannot be solely explained by the dissolved iron supply, given the poor solubility of dust-derived iron minerals. Here, we address this knowledge gap by investigating the interaction between semiconducting iron minerals and Synechococcus through extracellular electron transfer (EET). Using quantitative laboratory experiments integrated with an individual-based model, we assess the role of photoelectron-driven metabolism in oceanic primary production. We found that  photoelectrons from semiconducting iron oxides can enter the photosynthetic electron transport chain, significantly boosting cellular metabolism and CO₂ fixation. Crucially, our regional simulations reveal that this photoelectron-mediated pathway contributes to a significant fraction of the dust-driven net primary production increase in tropical and subtropical oceans, reaching its peak in the North Atlantic during autumn. These findings reveal that the direct energy transfer from semiconducting iron oxides is a previously unrecognized mechanism fundamentally shaping dust-driven marine biogeochemistry.