Sustainable carbon quantum dots extracted from biomass waste: Effective materials for environmental remediation applications

We explored the pivotal role of Carbon Quantum Dots (CQDs) in enhancing the efficiency of Industrial Wastewater Treatment (IWT) technologies. These nanoscale materials, when integrated into composite photocatalysts and photoanodes, significantly bolster processes like photocatalysis (PC) and photoelectrocatalysis (PEC), marking a significant leap in IWT management. The synergistic application of PC and PEC ushers in improved recycling rates, lower operational costs, shorter treatment durations, reduced carbon dioxide emissions, and the mitigation of secondary pollutants. Our research focuses on the synthesis of biomass waste-derived CQDs using peapods for their incorporation into existing IWT frameworks. Employing the hydrothermal method, we successfully synthesized these sustainable CQDs, confirmed by Transmission Electron Microscopy (TEM) and AC-High-Resolution TEM analyses, alongside a detailed examination of their morphological characteristics. Furthermore, CQDs/TiO₂ composite nanomaterials were synthesized using the hydrothermal method. The incorporation of CQDs facilitates the transfer and separation of photo-generated carriers, culminating in heightened photocatalytic activity. We characterized the structural, optical, and electronic properties of the CQD-decorated TiO2 nanocomposites using X-ray Photoelectron Spectroscopy (XPS) and fluorescence spectroscopy. XPS studies and AC-High-Resolution TEM analyses confirmed the effective synthesis and TiO₂ modification with CQDs. Photoluminescence studies highlighted the CQDs' ability to enhance charge separation, resulting in a reduction of the recombination of electron-hole pairs in TiO₂ which is crucial for effective photocatalysis. In conclusion, our research not only demonstrates the successful and sustainable synthesis of waste biomass-derived CQDs but also validates their efficacy as excellent candidates for PC and PEC in IWT applications, with ongoing studies aimed at further applications of these materials in IWT. This foundational work paves the way for further exploration in photocatalysis applications and beyond.