High-performance multifaceted silver nanoparticle/N-rich carbon dot electrocatalysts for oxygen reduction and ethanol oxidation

We synthesized cubic, silver-decorated nitrogen-doped carbon quantum dots (Ag/N-rCQDs) and tested their catalytic performance for the oxygen reduction (ORR) and ethanol oxidation (EOR) reactions in an alkaline medium. Upon the Ag/N-rCQDs electrode being exposed to an alkaline environment, the catalyst undergoes a rapid transformation into silver oxide. This transformation has been confirmed using several techniques. Given the large surface area, high nitrogen content, and ORR activity of N-rCQDs, the oxidized Ag/N-rCQDs exhibited excellent electrocatalytic activity for the ORR. This superior catalyst demonstrates near-ideal four-electron transfer, low charge transfer resistance (80 Ω.cm²), and a favorable Tafel potential (0.935 V vs. RHE) and half-wave potential (0.721 V vs. RHE). Additionally, multifaced Ag/N-rCQDs have shown promising performance for ethanol oxidation and the ability to self-regenerate by removing CO from their surface, as evidenced by electrochemical measurements (onset potential 0.5Vvs RHE). The results suggest that Ag/N-rCQDs hold significant promise as anode and cathode materials in direct ethanol fuel cells.