Magnetic Carbon Quantum Dot Nanocubes as High-Performance Catalysts for Transesterification

Global concern of increasing carbon emissions warrants the development of promising alternatives to nonrenewable fossil fuels such as conventional oil and diesel. However, due to lengthy purification procedure, cost-intensive processes, and unsustainable practices, the production of these fuels remains a challenge. Considering the aforementioned and the limitations of heterogeneous metal-based catalysts, we propose magnetic carbon dot nanocubes (PCDFe) as an efficient catalyst for transesterification of triacetin, a model reaction for biodiesel production. PCDFe nanocubes containing carboxyl and amino-functionalized carbon dots (CDs) and Fe nanoparticles were derived from l-proline and iron salts by one pot hydrothermal treatment. The magnetic nanocubes were successfully characterized using FTIR, SEM, TEM, XRD, BET, VSM, XPS, and TGA. The catalytic activity toward transesterification of triacetin, as a model compound for biodiesel production, was optimized with respect to reaction temperature, catalyst concentration, methanol:triacetin mole ratio, and reaction time. The studies revealed a 99.79% conversion in just 90 min under mild conditions with low catalyst loading and environmentally friendly solvents. The reusability and regeneration studies indicated efficient performance of the catalyst for eight cycles, without significant loss of catalytic activity. This reveals the robust nature of PCDFe catalyst and the sustainability of the process for biodiesel production applications.