Preparation of Salacca Peel Based Activated Carbon using CeCl3 Catalyzed Hydrothermal Carbonization and Microwave Induced KOH Chemical Activation as Ni-Ion Capacitor Electrode

Abstract

Activated carbon is a highly porous non-graphite carbon material. Activated carbon has been used for various applications, namely adsorbent, catalyst support and electrode. As supercapacitor's electrode, activated carbon has a high energy density and fast charge-discharge. In this study, salacca peel used as precursor to synthesized activated carbon through hydrothermal carbonization (HTC) and microwave induced chemical activation. The hydrochar (HC) was synthesized at 225°C, 5 bar for 5 h using cerium (III) chloride as catalyst. Furthermore, KOH was used as activating agent at various HC to KOH mass ratio at 1:2 (CE2), 1:3 (CE3), and 1:4 (CE4), under microwave irradiation at 700 W for 8 min. Activated carbon samples were analyzed using methylene blue adsorption capacity method, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The CE4 sample gave highest methylene blue adsorption capacity, indicating high surface area. This sample was used as nickel ion's capacitor electrode with nickel oxide as the reference electrode and 6 M KOH as the electrolyte. The electrochemical characteristic was studied using cyclic voltammetry (CV) with various scan rates (2 mV/s, 5 mV/s, 10 mV/s) for the nickel ion's capacitor electrode. It was obtained that CE4 provided higher capacitance compared to commercial activated carbon.