A photochemical approach to the synthesis of ZnO/CuO films and their application to the photocatalytic degradation of rhodamines (Rh-B and Rh-6G) under UV–Vis light irradiation

Hierarchical 0D CuO Wrapped by Petal-like 2D ZnO: A Strategic Approach of Superhydrophobic Melamine Sponge toward Wastewater Treatment

“…In Figure c, the deconvolution spectrum of the Cu 2p signal reveals two peaks at 953 and 933 eV, corresponding to Cu 2p 1/2 and Cu 2p 3/2 , respectively. A 20 eV separation between the peaks and the presence of satellite peaks confirms the existence of Cu 2+ in the form of CuO. , In Figure d, the deconvoluted spectrum of Zn 2p exhibits two peaks at 1045 and 1021 eV, corresponding to Zn 2p 1/2 and Zn 2p 3/2 , respectively. These assigned peaks reveal the existence of Zn 2+ in the form of ZnO. , Finally, in Figure e, the XPS spectrum of the O 1s band is represented with two symmetrical peaks, signifying distinct oxygen species on the surface of MS/CuO/ZnO.…”

“…To elucidate the chemical state of Zn, Cu, and O elements in MS/CuO/ZnO, XPS analyses were performed. In Figure b, the discernible peaks correspond to the elements Cu, Zn, and O, providing clear evidence of their presence . The C 1s peak observed at 286 eV in the survey spectra is attributed to the adventitious carbon, primarily a result of sample exposure in the ambient environment before XPS analysis .…”

“…A 20 eV separation between the peaks and the presence of satellite peaks confirms the existence of Cu 2+ in the form of CuO. 53,55 In Figure 2d, the deconvoluted spectrum of Zn 2p exhibits two peaks at 1045 and 1021 eV, corresponding to Zn 2p 1/2 and Zn 2p 3/2 , respectively. These assigned peaks reveal the existence of Zn 2+ in the form of ZnO.…”

“…To suggest a systematized method for the CuO/ZnO heterojunction in combating the degradation of pollutants, we determined the valence band (vb) edge position ( E vb ) and conduction band (cb) edge position ( E cb ) for both metal oxides determined by the Mulliken electronegativity theory: E vb = χ − E e + 0.5 E g E cb = χ − E e − 0.5 E g where χ is the absolute electronegativity of the photocatalyst, which is 5.7 eV for ZnO and 5.8 eV for CuO, and E e is the energy of the free electron given as 4.5 eV. Ultimately, the observed data of the optical band gap for each photocatalyst are represented by E g .…”

“…In Figure 2b, the discernible peaks correspond to the elements Cu, Zn, and O, providing clear evidence of their presence. 53 The C 1s peak observed at 286 eV in the survey spectra is attributed to the adventitious carbon, primarily a result of sample exposure in the ambient environment before XPS analysis. 54 In Figure 2c, the deconvolution spectrum of the Cu 2p signal reveals two peaks at 953 and 933 eV, corresponding to Cu 2p 1/2 and Cu 2p 3/2 , respectively.…”