Morphological Evolution of Carbon Quantum Dots to Carbon Nanoneedles and N/F Codoping as an Efficient Catalyst for Oxygen Electrochemistry

Fuel cells have emerged as a promising alternative to conventional energy sources due to their high energy conversion efficiency and low environmental impact. However, the development of efficient and cost-effective catalysts for fuel cell electrodes remains a significant challenge. Carbon quantum dots (CQDs) have emerged as promising candidates, with their unique electronic and optical traits, excellent electrochemical activity, and cost-effectiveness. We have synthesized CQD and investigated its structural transformation into carbon nanoneedles through N and F codoping, employing an innovative approach to enhance the efficiency, particularly in the field of oxygen electrochemistry. This process maximizes defects, reduces the band gap from 2.52 to 1.34 eV, and enhances the charge distribution in the carbon lattice, which facilitates easy e– transfer, as studied through density functional theory analysis. Notably, the N/F-CQD catalyst exhibits exceptional durability, maintaining ∼23 mV degradation after 30000 cycles, showcasing its robustness in prolonged operational conditions and finding its suitability for practical applications. Moreover, N/F-CQD exhibits a peak power density of 90 mW cm–2 at a load current density of ∼230 mA cm–2 under ambient pressure and a temperature of 50–55 °C, emphasizing its potential as an alternative nonmetallic catalyst. The introduction of N/F codoping demonstrates significant promise in enhancing the electrochemical behavior, paving the way for the development of a cost-effective and efficient nonmetal cathodic oxygen reduction reaction (ORR) electrocatalyst for anion-exchange membrane fuel cell applications.