Biomass-Derived Amorphous Carbon with Intrinsic Nitrogen Doping for Hydrogen Peroxide Electrosynthesis

Herein, amorphous carbon particles were synthesized from pumpkin seed biomass as a coproduct of a carbon quantum dot preparation route. The material was subsequently investigated as an electrocatalyst for the selective two-electron oxygen reduction reaction (2e– ORR) toward hydrogen peroxide production. The results demonstrate selectivity and stability comparable to those of conventional commercial carbon, while being obtained through a simple waste-valorization strategy without additional activation or external doping steps. SEM analysis revealed fragmented particles with irregular morphology and predominantly external surface area, consistent with the low porosity quantified by N2 adsorption (14.2 m2 g–1; pore volume 0.00597 cm3 g–1), while XPS analyses demonstrated the presence of oxygenated surface functionalities and verified endogenous nitrogen incorporation (∼1%), indicating successful self-doping derived solely from the precursor composition. Rotating disk electrode experiments showed an onset potential of 0.738 V vs RHE, and Koutecký–Levich analyses indicated an electron transfer number close to 2, in contrast to Vulcan XC-72, which displayed mixed 2–3e– behavior. Rotating ring-disc electrode measurements were also performed and confirmed high stability and selectivity, with an average H2O2 yield of ∼91.8% across 1.0–0.22 V and an average electron transfer number of 2.16. Additionally, chronoamperometry demonstrated outperforming compared to several reported carbon-based electrocatalysts. Thus, the results demonstrate that pumpkin seed-derived amorphous carbon is a sustainable and low-cost electrocatalyst with strong potential for decentralized H2O2 production via the 2e– ORR pathway.