CO2-activated graphite felt as an effective substrate to promote hydrogen peroxide synthesis and enhance the electro-Fenton activity of graphite/Fe3O4 composites in situ fabricated from acid mine drainage

1 Activating graphite electrodes to improve the selectivity of a 2-electron oxygen reduction reaction (ORR) and enhance heterogeneous Fenton catalyst loading is an effective method for restoring the water environment. Herein, the structures and properties of CO 2 -activated graphite felt (GF-CO 2 ), which achieves effective etching at high temperatures in CO 2 atmosphere, are evaluated. Oxygen-containing functional groups and defects are formed on the surface of GF-CO 2 , which improved the electrochemical behavior of GF, producing 2.86 times greater H 2 O 2 accumulation in an hour than GF-Raw. Using GFs as the anode in air-cathode fuel cells, GF@Fe 3 O 4 composites are fabricated in situ from acid mine drainage (AMD). The application of GF-CO 2 @Fe 3 O 4 as an electro-Fenton (E-Fenton) cathode exhibited efficient removal (98.8 %) and mineralizing (80.4 %) of chloroquine (CLQ) in 40 min and 240 min, respectively. Since it is favorable to enhance Fenton oxidation activities, the efficiency enhancement is attributed to the higher H 2 O 2 electrogeneration efficiency and metal content of the prepared GF-CO 2 @Fe 3 O 4 composite. The heterogeneous E-Fenton systems equipped with the GF-CO 2 @Fe 3 O 4 composite can be operated in a wide pH range and eliminate various organic pollutants . Thus, CO 2 activation of GF is a promising strategy to improve the efficiency of heterogeneous E-Fenton catalyst of GF@Fe 3 O 4 cathodes fabricated from AMD . This technology provides an environmentally friendly approach to restoring accessibility to fresh, clean water in an era where water scarcity threatens the water supply.