This paper reports solvothermal syntheses of pristine and KOH–NaCl-modified melon and melon–rGO composite films without post annealing and their applications in photocatalysis and Cu2+ sensing. Melon seed-layer coating enhanced film adhesion to fluorine-doped tin oxide substrates. X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy were used to verify melon film structures. Assorted complex agents were studied to tailor film morphologies. (001)-Oriented nanorods were observed in KOH–NaCl-modified melon films. Constituent elements were determined based on their binding energies using X-ray photoelectron spectroscopy. Ultraviolet–visible and ultraviolet photoelectron spectroscopy were employed to confirm band gaps and valence band positions, respectively, of melon films. Associated energy-band diagrams were then constructed. The melon–rGO composite films exhibited superior photodegradation of methylene blue (degradation rate constant [k] ≅ 6.4 × 10−3/min) and rhodamine B (k ≅ 2.5 × 10−3/min) under visible-light irradiation. The performance was confirmed by nanorod structures, low photoluminescence emission, and high electrochemical surface areas. Furthermore, a reliable photoelectrochemical current density (~0.5 mA/cm2) at a 0.6-V bias was obtained for KOH–NaCl-modified melon and melon–rGO composite films. The KOH–NaCl-modified melon films demonstrated excellent selectivity between Cu2+ and Cr6+, indicating promising applications in Cu2+ sensing.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry