Atomically Bonded S-Scheme Heterojunctions with Photothermal–Pyroelectric Synergy for Efficient H2O2 Photosynthesis

Solar-driven photocatalysis offers a sustainable pathway for energy conversion and environmental remediation, yet it is often hindered by inefficient charge separation and limited solar spectrum utilization. To address these challenges, this study introduces a novel design strategy by constructing a full-spectrum-responsive BiOBr/(Bi(Bi 2 S 3 ) 9 I 3 ) 0.667 S-scheme heterojunction that synergistically integrates photothermal and pyroelectric effects. This design utilizes the narrow band gaps (Bi(Bi 2 S 3 ) 9 I 3 ) 0.667 and localized surface plasmon resonance caused by oxygen vacancies as near-infrared response elements. Its inherent photothermal conversion capability provides an endogenous thermal field for the system, while the unique pyroelectric property of (Bi(Bi 2 S 3 ) 9 I 3 ) 0.667 generates a spontaneous polarization electric field under temperature fluctuations, thereby directionally driving charge carrier migration and effectively mitigating thermal-induced recombination. Concurrently, an atomically precise interface formed via shared Bi atoms establishes an efficient S-scheme charge transfer pathway, further promoting carrier separation and prolonging carrier lifetime. As a result, the optimized photocatalyst exhibits an exceptional H 2 O 2 production rate of 383.4 μmol g −1 h −1 and achieves efficient Cr(VI) reduction with a rate constant of 0.177 min −1 , demonstrating its potential as a multifunctional photocatalytic material. This work opens a new avenue for developing high-performance photocatalysts through the integration of atomic-level interfacial bridging with endogenous pyroelectric polarization. A full-spectrum-responsive BiOBr/(Bi(Bi 2 S 3 ) 9 I 3 ) 0.667 S-scheme heterojunction with Bi atom-shared interfaces integrates photothermal and pyroelectric effects, enabling efficient charge separation and achieving superior H 2 O 2 production and Cr(VI) reduction. 1. Full-spectrum solar absorption with strong photothermal effect. 2. Pyroelectric fields from photothermal fluctuations promote charge separation. 3. Key contribution of photothermal–pyroelectric synergy. 4. Achieve efficient H 2 O 2 photosynthesis and Cr(Ⅵ) reduction.