Metal-free electrocatalysts obtained from agave waste by solar pyrolysis for oxygen reduction reaction

Characterization and electrochemical evaluation of novel metal-free electrocatalysts obtained by solar pyrolysis is reported. Carbon-based electrocatalysts were prepared from agave bagasse waste, using a sustainable process based on concentrated solar energy as heat source. Agave was processed in a spherical borosilicate glass solar reactor using a heating rate of 30 degrees C min(-1) to a target of 500, 700, or 900 degrees C, and maintaining temperature for 1 h under inert atmosphere. The structure and composition of the prepared electrocatalysts were influenced by pyrolysis temperature. In addition, electrocatalytic activity towards the oxygen reduction reaction in 0.1 M KOH solution was explored. The electrocatalyst obtained at 500 degrees C showed the highest activity among all pyrolyzed samples due to its moderate surface area, but mostly due to its higher oxygen content. The metal-free electrocatalysts reported in this work are promising eco-friendly alternative as cathode materials for anion-exchange membrane fuel cells. This study provides a sustainable approach to use agricultural biomass waste to produce valuable materials for electrochemical energy devices. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study reports the characterization and electrochemical evaluation of novel metal-free electrocatalysts obtained by solar pyrolysis from agave bagasse waste. The electrocatalysts' structure and composition were found to be influenced by pyrolysis temperature, with the sample pyrolyzed at 500 degrees Celsius showing the highest activity. The metal-free electrocatalysts could serve as promising eco-friendly alternatives for anion-exchange membrane fuel cells.