Synergy between nitrogen, phosphorus co-doped carbon quantum dots and ZnO nanorods for enhanced hydrogen production

Abstract

We report a facile synthesis of nitrogen and phosphorus co-doped carbon quantum dots (NPCQDs) anchored on ZnO nanorods to form NPCQDs/ZnO (NPCZ) nanohybrid as efficient and robust photocatalysts for light-driven hydrogen production. The synthesized NPCZ catalyst exhibited improvement in hydrogen production of 417 μmolh−1g−1 under visible light compared to nitrogen doped CQDs/ZnO (NCZ), phosphorus doped CQDs/ZnO (PCZ) and CQDs/ZnO (CZ) nanohybrid photocatalysts. The synergistic interactions between NPCQDs and ZnO nanorods give rise to the formation of additional energy levels, decrease in recombination rate and increase in decay lifetime of photo-generated electron hole pairs, reduced work function, thus the eventual improved hydrogen generation performance in visible region. Further, the experimentally obtained results are consistently corroborated by the first principles Density Functional Theory (DFT), revealing the decrease in bandgap as well as work function and improvement in density of states (DOS) of NPCZ photocatalyst.