The Effect of N-Doping on the Synergy between Adsorption and 2e-Orr Performance of Activated Carbon Cathode in an Electro-Fenton System

Abstract

The adsorption of carbon materials and 2e-ORR performance can be promoted by N-doping. However, the effect of different N-doping types on adsorption and 2e-ORR and their synergy is not clear, which limits the development of an electro-Fenton system. We used the multi-scale simulation method to elucidate the mechanism by which different N-doping types promote the cathode adsorption and 2e-ORR performance of carbon materials by performing molecular dynamics and quantum chemical simulation. We also investigated the synergy between adsorption and 2e-ORR by performing electro-Fenton experiments. The results showed a synergistic effect between adsorption and 2e-ORR performance. Improving only one of the properties resulted in a poor degradation effect of the electro-Fenton system. Additionally, pyridinic-N and pyrrolic-N showed a cooperative effect and promoted the capacity of activated carbon to adsorb tetracycline. Graphitic-N and pyridinic-N greatly improved the selectivity of 2e-ORR, which strongly favored the formation of H2O2. The synergy between adsorption and the 2e-ORR of the MAC electrode was high because of its suitable N-doping type ratio. Under the action of high-efficiency synergy, the degradation effect of tetracycline by the electro-Fenton cathode was 8.72%-11.64% higher than that of other modified cathodes. Our findings indicated the direction for N-doping modification of the cathode in the electro-Fenton system.

Keywords: N-doped cathode, electro-Fenton, molecular dynamics simulation, quantum chemical simulation, activated carbon