A fluorine doped carbon aerogel prepared from the spent cathode carbon of aluminum electrolysis towards electrocatalytic synthesis of H2O2†

Abstract

The sustainability of aluminum electrolysis spent cathode carbon (SCC) is currently an urgent environmental issue that needs to be addressed. In this work, fluorine doped carbon aerogels (SCC-FCAs) were prepared by a series of auxiliary purification methods using the graphite phase and fluoride salt phase of SCC in aluminum electrolysis. The obtained SCC-FCAs were used for electrocatalytic synthesis of H₂O₂ and their performance was evaluated. The experimental results showed that the selectivity of SCC-FCA-500 (heat treatment at 500 °C) reached 87.2%, and the highest yield could reach 900.1 mmol g⁻¹ h⁻¹. The density functional theory calculation results showed that the covalent C–F bond model has weaker adsorption capacity for *OOH than the semi-ionic C–F bond. In addition, the intersite of the semi-ionic C–F in SCC-FCA-500 is the active site for the adsorption of the intermediate *OOH. This work proposed a self-synthesis strategy of using SCC from aluminum electrolysis, which provided a case for the high-value utilization of SCC in the direction of new energy resources.