Synergistically S/N self-doped biochar as a green bifunctional cathode catalyst in electrochemical degradation of organic pollutant

Biomass-derived heteroatom self-doped cathode catalysts has attracted considerable interest for electrochemical advanced oxidation processes (EAOPs) due to its high performance and sustainable synthesis.Herein,we illustrated the morphological fates of waste leaf-derived graphitic carbon (WLGC) produced from waste ginkgo leaves via pyrolysis temperature regulation and used as bifunctional cathode catalyst for simultaneous H₂O₂ electrochemical generation and organic pollutant degradation,discovering S/N-self-doping shown to facilitate a synergistic effect on reactive oxygen species (ROS) generation.Under the optimum temperature of 8000°C,the WLGC exhibited a H₂O₂ selectivity of 94.2% and tetracycline removal of 99.3% within 60 min.Density functional theory calculations and in-situ Fourier transformed infrared spectroscopy verified that graphitic N was the critical site for H₂O₂ generation.While pyridinic N and thiophene S were the main active sites responsible for _•OH generation,Nvacancies were the active sites to produce ¹O₂ from O₂.The performance of the novel cathode for tetracycline degradation remains well under a wide pH range (3–11),maintaining excellent stability in 10 cycles.It is also industrially applicable,achieving satisfactory performance treating in real water matrices.This system facilitates both radical and non-radical degradation,offering valuable advances in the preparation of cost- effective and sustainable electrocatalysts and hold strong potentials in metal-free EAOPs for organic pollutant degradation.