A novel design of SiH/CeO2(111) van der Waals type-II heterojunction for water splitting

Abstract

Searching for economical low-dimensional materials to construct the highly efficient type-II heterojunction photocatalysts for splitting water into hydrogen is very strategic. In this study, using the first-principles calculations, we construct a novel SiH/CeO₂(111) type-II heterojunction with a very small lattice mismatch of less than 1%. Based on AIMD simulation and phonon dispersion calculations, the SiH/CeO₂(111) heterojunction reveals sufficient stability, and is easy to synthesize. Due to the vdW interaction between SiH and CeO₂(111) components, electron and hole accumulation regions form at the heterojunction interface, which is very conducive to the separation of photoexcited electron–hole pairs. Besides, the SiH/CeO₂(111) heterojunction has good visible light response, and even a strong absorption peak of up to 8.7 × 10⁵ cm⁻¹ in the high-energy visible region. More importantly, the SiH/CeO₂(111) heterojunction exhibits good OER and HER performance because its oxidation and reduction potentials well meet the requirements of water splitting. Consequently, SiH/CeO₂(111) is a potential photocatalyst for splitting water to hydrogen.