Internal electric field-engineered CuS@SrTiO3 S-scheme heterojunction for enhanced photocatalytic H2 generation

The design of S-scheme heterojunctions with an internal electric field (IEF) provides an effective approach to facilitate the separation of photogenerated carriers. In this work, we strategically constructed a CuS@SrTiO₃ heterojunction through hydrothermal synthesis, anchoring non-noble plasmonic CuS nanoparticles onto SrTiO₃ surfaces. Density functional theory (DFT) calculations demonstrates that an IEF is established at the CuS@SrTiO₃ interface due to the work function difference, driving the photogenerated carriers to migrate rapidly along an S-scheme pathway. Experimental evidence confirms that the interfacial coupling synergizes with the localized surface plasmon resonance (LSPR) effect of CuS, simultaneously broadening light absorption and establishing directional carrier migration pathways. The resultant CuS@SrTiO₃ heterojunction demonstrates exceptional photocatalytic H₂ generation performance, achieving production rates 10.84 and 207.05 times higher than those of pristine SrTiO₃ and CuS, respectively. This study highlights the critical role of interface design in manipulating charge transfer routes, offering a universal strategy for developing high-performance S-scheme photocatalysts through tailored interfacial interactions.