Green Synthesis of a CuO-ZnO Nanocomposite for Efficient Photodegradation of Methylene Blue and Reduction of 4-Nitrophenol

Aklilu Guale Bekru; Lemma Teshome Tufa; Osman Ahmed Zelekew; Mahendra Goddati; Jaebeom Lee; Fedlu Kedir Sabir

doi:10.1021/acsomega.2c02687

Green Synthesis of a CuO-ZnO Nanocomposite for Efficient Photodegradation of Methylene Blue and Reduction of 4-Nitrophenol

ACS Omega. 2022 Aug 26;7(35):30908-30919. doi: 10.1021/acsomega.2c02687. eCollection 2022 Sep 6.

Authors

Aklilu Guale Bekru¹, Lemma Teshome Tufa^{1

2}, Osman Ahmed Zelekew³, Mahendra Goddati⁴, Jaebeom Lee⁴, Fedlu Kedir Sabir¹

Affiliations

¹ Department of Applied Chemistry, Adama Science and Technology University, Adama 1888, Ethiopia.
² Research Institute of Materials Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea.
³ Department of Materials Science and Engineering, Adama Science and Technology University, Adama 1888, Ethiopia.
⁴ Department of Chemistry, Chemistry Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea.

Abstract

CuO-ZnO nanocomposites (NCs) were synthesized using an aqueous extract of Verbascum sinaiticum Benth. (GH) plant. X-ray diffraction (XRD), spectroscopic, and microscopic methods were used to explore the crystallinity, optical properties, morphology, and other features of the CuO-ZnO samples. Furthermore, catalytic performances were investigated for methylene blue (MB) degradation and 4-nitrophenol (4-NP) reduction. According to the results, CuO-ZnO NCs with 20 wt % CuO showed enhanced photocatalytic activity against MB dye with a 0.017 min^-1 rate constant compared to 0.0027 min^-1 for ZnO nanoparticles (NPs). Similarly, a ratio constant of 5.925 min^-1 g^-1 4-NP reductions was achieved with CuO-ZnO NCs. The results signified enhanced performance of CuO-ZnO NCs relative to ZnO NPs. The enhancement could be due to the synergy between ZnO and CuO, resulting in improved absorption of visible light and reduced electron-hole (e^-/h⁺) recombination rate. In addition, variations in the CuO content affected the performance of the CuO-ZnO NCs. Thus, the CuO-ZnO NCs prepared using V. sinaiticum Benth. extract could make the material a desirable catalyst for the elimination of organic pollutants.