Engineering Cu2O@BN photocatalytic heterojunction for synchronous kinetic enhancement and reaction pathway regulation in peroxymonosulfate activation.

The robust redox cycle of the catalytic center is essential for enhancing sustainable water purification in Fenton-like catalysis. However, the unequal of electron donation and acceptance, especially slow reductive half-reactions, often limit the process. Herein, we developed a photocatalytic heterojunction by integrating cuprous oxide (Cu2O) with hexagonal boron nitride (h-BN). The h-BN component acts as an electron sink, promoting electron-hole pair separation and efficient Cu+ regeneration. This design enhances peroxymonosulfate (PMS) activation for bisphenol A (BPA) degradation, achieving rate constants 3.79 and 12.22 times higher than Cu2O/PMS/Light and Cu2O/PMS systems, respectively. Moreover, the formation of the heterojunction optimizes the electronic structure of Cu2O by upshifting the d-band center. This results in stronger PMS adsorption compared to pristine Cu2O. Enhanced surface binding weakens the O-O bond in PMS, enabling a shift from a nonradical to a mixed radical-nonradical degradation pathway for BPA. This strategy offers an effective approach of heterostructures to modulating both the kinetics and pathways of Fenton-like catalysis for environmental remediation.