Construction of S-scheme MnO₂@CdS heterojunction with core–shell structure as H₂-production photocatalyst

Artificial photosynthesis is deemed as an efficient protocol for transforming abundant solar energy into valuable fuel. In this paper, the well-defined one-dimensional (1D) core–shell MnO₂@CdS hybrids were constructed by employing MnO₂ nanotubes and CdS nanoparticles as nano-building blocks via a chemical co-precipitation route. The rationally designed core–shell structure provided an intimate heterojunction interface between the CdS shell and MnO₂ core. All the MnO₂@CdS core–shell nanocomposites possess higher H₂ evolution rate through visible light irradiation contrary to pristine CdS, and the optimal MnO₂@CdS hybrid exhibits the utmost H₂ evolution rate of 3.94 mmol·g⁻¹·h⁻¹, which is 2.8-fold higher compared with that of CdS. Appertaining to XPS and Mott-Schottky (M-S) analysis, such enhanced photocatalytic H₂ generation of MnO₂@CdS heterojunction was ascribed to an S-scheme mechanism, which suppressed the charge recombination along with a fast detachment of electron–hole pairs (e⁻–h⁺) and significantly improved the severance of carriers, thus improved H₂ evolution performance. These findings envision a new insight into the development of S-scheme heterostructure for photocatalytic H₂ generation.