Investigation of dual-functional carbon cathode catalysts from agricultural wastes in the heterogeneous electro-Fenton process

In heterogeneous electro-Fenton process, the design of electrocatalysts for in-situ generation of H2O2 and efficient conversion to •OH remains a challenge. Herein, a simple one-step pyrolysis strategy has been developed to synthesize green and stable dual-functional electro-catalysts from agricultural wastes. The biochar of soybean roots (RSBC) with ample -COOH and C-O-C functional groups exhibited considerable capacity for H2O2 production (21.6 mM at −0.4 V vs RHE), and the dual-functional electron-catalyst exhibits an excellent catalytic reaction for antibiotics removal (100 % cloroquine phosphate with kobs=0.035 min−1). The ultra-small MnO nanoclusters (<2 nm) in the biochar of Phytolacca americana leaves (LPBC) were the active center via the transfer of electrons between adsorbed H2O2 and Mn atoms to produce reactive •OH, as identified by operando X-ray absorption fine structure (XAFS) spectroscopy and density functional theory calculations. This work provides a new direction in the design of dual-functional carbon cathode catalysts for environmental remediation.