Increasing nitrogen source by chitosan coupled with nZVI-jelly fig peel biochar to improve O₂ reduction to H₂O₂ and...

The electrocatalytic process of two-electron oxygen reduction reaction (ORR) presents a promising strategy for synthesizing H₂O₂. Nitrogen-doped carbon materials have attracted considerable interest in their performance as highly active and selective electrocatalysts in this reaction. This study was conducted to produce biochar from the high‑nitrogen content of jelly fig (Ficus pumila var. awkeotsang) peel by pyrolysis, and the biochar was compounded with zero-valent iron as the cathodic catalyst for an electrocatalytic system. Functional groups such as OH, CO, and NH were abundant on the biochar surface produced by heating the jelly fig peel at 600 °C. A 2.6 % N element can enhance the conductivity of the catalyst, while other functional groups can increase the ORR activity on the cathode surface. The hydrothermal synthesis of chitosan and jelly fig peel produced the catalyst, heating the components in a pressurized vessel to facilitate the formation of the catalyst. The catalyst exhibited a high content of oxygen atoms (60.5 %) on the cathode surface, improving the low-oxygen atoms after the high-temperature pyrolysis of biochar. The cathode doped with zero-valent iron compounded with jelly fig peel biochar achieved a high H₂O₂ yield of 517.5 mg/L, a current efficiency of 81.6 %, and favorable stability.