Surface defect-rich ceria quantum dots anchored on sulfur-doped carbon nitride nanotubes with enhanced charge separation for solar hydrogen production

Designing defect-engineered semiconductor heterojunctions can effectively promote the charge carrier separation. Herein, novel ceria (CeO 2 ) quantum dots (QDs) decorated sulfur-doped carbon nitride nanotubes (SCN NTs) were synthesized via a thermal polycondensation coupled in situ deposition-precipitation method without use of template or surfactant. The structure and morphology studies indicate that ultrafine CeO 2 QDs are well distributed inside and outside of SCN NTs offering highly dispersed active sites and a large contact interface between two components. This leads to the promoted formation of rich Ce 3+ ion and oxygen vacancies as confirmed by XPS . The photocatalytic performance can be facilely modulated by the content of CeO 2 QDs introduced in SCN matrix while bare CeO 2 does not show activity of hydrogen production . The optimal catalyst with 10% of CeO 2 loading yields a hydrogen evolution rate of 2923.8 μmol h −1 g −1 under visible light, remarkably higher than that of bare SCN and their physical mixtures. Further studies reveal that the abundant surface defects and the created 0D/1D junctions play a critical role in improving the separation and transfer of charge carriers, leading to superior solar hydrogen production and good stability.