The localized surface plasmon resonances (LSPR) of noble metal nanostructures provide appealing strategies to enhance photocatalytic reactivity. Plasmonic hot charge carrier production for direct catalysis by plasmonic metals or heterostructures, and plasmonic Electric (E-) field enhancement of resonant intramolecular transition processes represent two major mechanisms of plasmonic photocatalysis. Harnessing plasmonic E-fields for photocatalysis, however, is fundamentally challenged by a trade-off between distance-dependent local field intensity enhancement and excited state quenching through the metal surface. Here, we explore quantitative optimization of photocatalysis mediated by an E-field enhanced metal-to-ligand charge transfer (MLCT) process. We present a hierarchical photoreactor architecture that localizes a transition metal photocatalyst, [Ru(bpy)3]2+, in an electromagnetic “sweet spot” around Ag nanoantennas for efficient plasmonic enhancement of photocatalysis. A phospholipid membrane self-assembled around the Ag nanoparticle (NP) binds [Ru(bpy)3]2+ as well as serves as a spacer between the transition metal complex and the NP, whose LSPR overlaps with the [Ru(bpy)3]2+ MLCT. The photoreactor allows for substantial absorption enhancement, but avoids quenching of photoexcited Ru*(II) state. We demonstrate direct photocatalytic urea oxidation with the Ag-[Ru(bpy)3]2+ photoreactors, and implement a visible light-driven Direct Urea Fuel Cell (LDUFC) to achieve simultaneous solar energy harvesting and waste water treatment. Our approach provides great promise as an effective and broadly applicable strategy to enhance intramolecular charge or energy transfer processes with metal plasmon resonances. It also depicts a blueprint for the designs of bio-mimetic, efficient and selective nanoreactors.