Cu-doped Bi2O3/Bi0 composite as an efficient Fenton-like catalyst for degradation of 2-chlorophenol

• Cu-doped Bi2O3/Bi0 showed high Fenton activity and stability at circumneutral pH.
• H2O2 was mainly converted into OH through Bi0-dependent inhibition of H2O2 oxidation.
• Bi0 reduced Cu2+ to Cu+, enhancing the reaction of H2O2 with Cu+ to produce OH.
• 2-CP was attacked mainly by OH and mineralized into CO2, H2O and Cl−.

Cu-doped BiOx composites were prepared with and without citric acid. In the presence of citric acid, Bi0 and Cu2+/Cu+ were confirmed to coexist in the composite (BiCu9/Bi0) by X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst showed high Fenton activity and stability for the degradation and mineralization of 2-chlorophenol in the pH range of 6–8. H2O2 was predominately converted into OH radicals in BiCu9/Bi0 suspension, as assessed by the electron spin resonance technique. In the composite, Bi0 inhibited the oxidation of H2O2 by Cu2+ into O2 and OH by reducing Cu2+, enhancing the reaction of H2O2 with Cu+ to produce OH. Intermediate determination showed that 2-chlorophenol was decomposed mainly by OH radicals into hydroxylation products, subsequently decomposed into short-chain organic acids, and eventually decomposed into CO2 and H2O.

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