Combined effect of Cu0 and oxygen vacancies in Cu-based zeolites enables highly efficient photo-Fenton-like performance for water purification

Abstract

The Cu-based heterogeneous photo-Fenton-like process has emerged as a promising technology in wastewater treatment, but efficient light harvesting and sufficient utilization of photogenerated electrons are still core issues. Herein, a dual strategy was proposed to achieve the high-efficiency removal of refractory organic pollutants using a Cu-doped zeolite with Cu⁰ and oxygen vacancies (Cu⁰@CuZ) in the photo-Fenton-like reaction. This is the first time that such a strategy employing Cu-based zeolites has been used. Cu⁰@CuZ can completely degrade 20 mg L⁻¹ phenol within 15 min under visible-light irradiation, and the rate constant was 40, 55, and 65 times higher than Cu₂O, CuO, and Cu⁰, respectively. Cu⁰@CuZ also presented excellent degradation performance for other typical refractory organic pollutants, surpassing most of the reported Cu-based catalysts to date. This superior performance highly depends on oxygen vacancies (Vo) and plasmonic Cu nanoparticles. The introduction of Vo and the creation of the surface plasmon resonance effect greatly enhanced the visible-light harvesting ability of the catalyst. Impressively, Vo and Cu⁰ nanoparticles served as dual-channels for efficient electron transfer by enriching and then transferring photogenerated electrons to Cu(II), greatly expediting the reduction of Cu(II) to Cu(I). The synergistic effects of the dual-channel electron transfer and light-harvesting ability achieved sustained Cu(II)/Cu(I) cycling, thereby promoting H₂O₂ activation to produce more active species for organic pollutant degradation. This work provides an ingenious strategy to rationally establish a high-efficiency photo-Fenton-like catalyst for water remediation.