Dual‐Type Polarization‐Triggered Spontaneous Exciton Dissociation in Conjugated Polymers for Enhanced Photocatalytic H 2 O 2 Evolution in Pure Water

Abstract Severe exciton effect significantly hinders free‐charge‐involved water redox reactions, limiting the improvement of photocatalytic performance. Herein, a dual polarization strategy was proposed to achieve spontaneous exciton dissociation while lowering exciton binding energy by introducing B←N bonds and triazine as the dual‐type polarization unit into the alkynyl‐linked conjugated backbone. Dual‐type polarization centers can induce spontaneous exciton dissociation (exciton activation energy <25 meV) to generate more free charges that participate in water oxidation reactions. Triazine as the second polarization unit, lowers the energy barrier of the H 2 O oxidation reaction and serves as the active site of the O 2 reduction reaction to accelerate H 2 O 2 ‐evolution. The H 2 O 2 ‐evolution performance of the dual‐polarization photocatalyst reaches up to 4261 µmol g −1 h −1 with a superb apparent quantum yield of 25.84% at 420 nm and solar‐to‐chemical energy conversion up to 1.20% in pure water, surpassing most of the H 2 O 2 ‐evolution organic photocatalysts ever reported. Furthermore, the dual‐polarization photocatalyst exhibits strong universality in complex water bodies (lake water, river water, and seawater), while achieving higher H 2 O 2 ‐evolution performance than that in pure water.