Fabrication of N-CQDs@W18O49 heterojunction with enhanced charge separation and photocatalytic performance under full-spectrum light irradiation

Increasing the charge separation and the utilization efficiency of sunlight are essential factors in a photocatalytic process. In this study, we prepared crystalline N-CQDs@W₁₈O₄₉ heterostructures, through the in situ growth of W₁₈O₄₉ nanocrystals on nitrogen-doped carbon quantum dots (N-CQDs). N-CQDs@W₁₈O₄₉ nanocomposites showed high activity in the photodegradation of ciprofloxacin (CIP) and methyl orange (MO). The photodegradation activity of the optimized N-CQDs@W₁₈O₄₉-5 sample was four times higher than that of W₁₈O₄₉ under ultraviolet-visible (UV–vis) light irradiation. The photodegradation activity of N-CQDs@W₁₈O₄₉-5 sample was two times higher than that of W₁₈O₄₉ under near-infrared (NIR) light irradiation. The enhanced photosensitivity of the nanocomposites was attributed to the promotion of charge separation by N-CQDs and the local surface plasmon resonance (LSPR) effect of W₁₈O₄₉ under NIR light irradiation. This work provides a promising approach for designing and manufacturing photocatalysts with full-spectral responsiveness and improved charge separation.