Controlling the up-conversion photoluminescence property of carbon quantum dots (CQDs) by modifying its surface functional groups for enhanced photocatalytic performance of CQDs/BiVO4 under a broad-spectrum irradiation

The different surface functional groups of carbon quantum dots (CQDs) affect their optical property, especially the up-conversion photoluminescence (UCPL) property. In this study, the CQDs/BiVO4 composite photocatalyst was synthesized by a simple hydrothermal process. The prepared photocatalysts were comprehensively characterized. The photocatalytic activity of CQDs/BiVO4 was tested by degrading rhodamine B (RhB). The photocatalytic removal rate of RhB with BiVO4 was largely enhanced by incorporation of CQDs. The enhanced photocatalytic performance was mainly attributed to the broadened response spectra generated by the UCPL of CQDs. Furthermore, loading CQDs had improved the separation efficiency of photogenerated carriers, resulting in the photocatalytic performance increasement of CQDs/BiVO4. The content of surface graphitic nitrogen and oxygen-containing groups on CQDs could adjust its UCPL wavelength and intensity, and ultimately adjust photocatalytic ability of composite photocatalysts. More surface graphitic nitrogen and oxygen-containing groups on CQDs could benefit the photocatalytic ability of CQDs/BiVO4. Free radical scavenging experiments determined that the holes (h(+)) and hydroxyl radicals (center dot OH) played a crucial role in the photodegradation process.

Automated summary

The addition of CQDs in BiVO4 composite photocatalyst significantly enhanced the photocatalytic activity by broadening response spectra and improving separation efficiency of photogenerated carriers.