Matibag VKR, Geronimo HGD, Garcia JL, Tongol BJV. Platinum-Free Electrocatalyst for Oxygen Reduction Reaction Derived from the Direct Pyrolysis of Waste Watermelon Peels. IJIE. 2019;11(7):175-181. Accessed April 7, 2026. https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/4639