Coconut shell-derived porous activated carbon materials: Role of activating agent on physico-electrochemical properties and photovoltaic performances.

The exploration of abundant and sustainable biomass materials for energy conversion applications is an environmental approach. In the present work, we prepare activated carbons (ACs) from coconut shells at a low temperature (230 °C) carbonization process followed by various chemical activation approaches. KOH and ZnCl₂ were used as activating agents and their effects on the physical and chemical properties were studied. The formations of ACs were confirmed by XRD and FTIR. The degrees of defects were studied via Raman spectroscopy, which shows that KOH-based AC (ACK) gives better electrocatalytic properties than ZnCl₂-based AC (ACZ). Morphological scrutiny was done by FE-SEM and the high level of porosity in ACK material was observed. BET reveals a large amount of macro and mesopores present in ACK facilitates the transportation and diffusion of electrolyte ions in the electrolyte-counter electrode interface. ACK exhibits an oxidation peak current density of 3.5 mA/cm², which is higher than ACZ based electrodes. The maximum power conversion efficiency of 13.1% is achieved by using ACK as counter electrode material in DSSC under 800 lux illumination. Our research suggests that biomass-derived KOH-activated carbon with hierarchical pores is a promising material for the cost-effective counter electrode and sustainable for indoor photovoltaic applications. [ABSTRACT FROM AUTHOR]