Electrocatalytic membrane with p-block bismuth atoms for selective oxygen activation to hydroxyl radicals for effective water decontamination

Herein, individual p-block bismuth (Bi) atoms are dispersed onto N-doped Ti3C2Tx MXene (BiN3/MXene) to enhance the 3e− oxygen reduction reaction (ORR), for the electrosynthesis of hydroxyl radicals (HO•) via the activation of molecular oxygen (O2). Theoretical calculations and experiments reveal that the p-orbitals of Bi atoms can readily hybridize with the p-orbitals of O, which enables the transfer of charges, creates sufficient strength of adsorption for oxygen intermediates, lowers the activation energy, and modulates the rate-limiting reaction. The optimized generation of HO• is up to 26.7 μmol/(L·h·cm2) without additional chemical reagents, facilitating efficient removal of micropollutants from complex water matrices. Specifically, the rate constant (kobs) for sulfamethoxazole degradation achieves 1.027 min−1, outperforming the reported processes for micropollutants removal. This work illuminates the atomic-level construction of a p-block BiN3/MXene electrocatalytic membrane to efficiently perform the 3e− ORR and highlights the substantial potential for wastewater decontamination.