Light-Driven Selective Chlorine and Hydrogen Co-Evolution from Seawater via Plasmonic Energetic Carrier Filter

Solar-driven chlorine and hydrogen co-evolution from seawater represents an energy-conservating and clean alternative to the conventional chlor-alkali industry. However, sustained and selective chlorine production remains extremely challenging due to competition from the thermodynamically less demanding water oxidation side reaction. In this work, we demonstrate a Ni/Ni 2 SiO 4 plasmonic matrix catalyst that enables a distinct energetic charge carrier filter effect for wavelength-controlled selective chlorine and hydrogen co-production. Based on the distinct energy band structure, the plasmonic-mediated energetic charge filter drives the extraction of higher-energy “hot” holes and lower-energy “cold” electrons, respectively, through lower- and higher-wavelength photons. This phenomenon, combined with hierarchical plasmon coupling and promoted carrier dynamics, collectively led to the cooperative facilitation of both the oxidative and reducing half reactions. In situ spectroscopic investigations point at preferentially promoted chloride adsorption and activation via a two-step, nonradical chlorine evolution pathway, leading to favorable Cl 2 and H 2 yield rates with near-unity Cl 2 selectivity in photocatalytic measurements with seawater. The plasmon-mediated energetic charge carrier filter mechanism opens intriguing pathways for preferential reaction engineering with effective product control.