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Adenine-based noble carbon; Ethanol electrooxidation; PEM cell; Green Hydrogen; Chemicals production
Abstract:
Herein, adenine-derived noble carbons are used as anodic supports for PtRu nanoparticles for the ethanol oxidation reaction (EOR). Three noble carbons were synthesized using salt melts as templates and denoted as ANZ, ALZ and ALK depending on the precursor (LiCl/ZnCl, NaCl/ZnCl and LiCl/KCl). Their large nitrogen content and pore volume (ANZ > ALZ > ALK) facilitate the formation of small PtRu nanoparticles (2–3 nm), while variations in the C/N ratio and surface area deeply affected the alloy formation (0–58%). In a half-cell configuration, PtRu/ANZ exhibited the highest activity (443 mA/mgPtRu), followed by PtRu/ALZ and PtRu/ALK, due its higher dispersion degree and lower alloying percentage. More interestingly, PtRu/ANZ and PtRu/ALZ presented 2.4 and 1.6 larger mass activity than commercial PtRu/C. Regarding the ethanol electrolysis, the best materials were scaled up to a proton exchange membrane cell. Acetaldehyde was the major compound followed by acetic acid and ethyl acetate (anode), while hydrogen was produced with 100% faradaic efficiency (cathode). PtRu/ANZ provided the best electrochemical performance, shifting the acetic acid production to a lower potential (0.6 V), requiring lower energy (~35kWh/kgH2 at 1 A) than commercial water electrolyzers. These promising results set a precedent for high nitrogen containing supports for EOR electrocatalysts.
