Construction of biochar heterojunctions decorated with nanoscale zero-valent copper and CeOx for synergistically enhanced Fenton-like degradation of glyphosate

Glyphosate has received a great deal of attention due to its persistence in the environment and its potential carcinogenicity. Traditional Fenton catalytic methods for glyphosate removal are often hindered by the aggregation and passivation of catalysts, and the formation of toxic intermediates, such as aminomethylphosphonic acid (AMPA). In this study, a synergistic heterojunction comprising nano-zero-valent copper (nZVC) and CeO x was engineered on a biochar (BC) interface (nZVC/CeO x @BC) to investigate the behavior and mechanism of glyphosate degradation. The results showed that glyphosate removal reached 96.9% within 20 min, and complete degradation was achieved within 60 min in the nZVC/CeO x @BC/H 2 O 2 system. Importantly, the catalyst could be used in a pH range of 2–10, and the degradation efficiency of this catalyst remained above 95% even after six cycles. DFT calculations and experimental results revealed that the heterostructure facilitates interfacial electron transfer through the formation of electron bridges and the reversible Ce(III)/Ce(IV) redox couple. This enhanced electron-transfer pathway promoted the continuous activation of H 2 O 2 and generation of reactive oxygen species, thereby accelerating the oxidation and degradation of glyphosate while suppressing active-site deactivation and improving catalyst stability. Moreover, the degradation pathway was diverted towards the formation of the environmentally benign compound glycine (70.95 μM, conversion rate ≈ 60%), thus suppressing the formation of AMPA (0.18 μM, conversion rate ≈ 0.15%). This study highlights the crucial role of interfacial electron-transfer-enhanced heterojunctions in regulating glyphosate degradation pathways and provides an effective strategy for efficient glyphosate degradation.