Abstract
Aluminium oxide (Al2O3), otherwise known as alumina, is extensively utilised in various products ranging from electronics, ceramics, thermal, and catalysts. Al2O3 has a number of different phases: γ, η, δ, θ, κ, χ and ρ, with the γ form widely utilised as a catalyst in industrial applications. Although Al2O3 has a wide range of uses, limited studies have been done on detecting organosulfur compounds, such as thiourea (TU), which is an industrial compound that is utilised in chemical and biomedical applications. Therefore, in this study γ-Al2O3 quantum dots (γ-Al2O3QDs) are used as a sensor material to sense TU in Phosphate Buffered Saline (PBS). The γ-Al2O3QDs were processed hydrothermally, and the recovered powder was characterised with an X-ray diffraction pattern (XRD), scanning electron (SE) and transmission electron microscopy (TEM) and Fourier transform infra-red spectroscopy (FT IR). The experimental setup had a layer of γ-Al2O3QDs pasted onto a glassy carbon (GC) electrode and dried in order to make the sensing efficiency of the three electrode system. The γ-Al2O3QDs/GCE based sensor was tested with very low to high concentrations of TU (3.56, 7.815, 15. 625, 31.25, 62.5, 125, 250, 500, and 1000 μM in PBS) and variable potentials (1 ×10−2, 2 ×10−2, 3 ×10−2, 4 × 10−2, 5 ×10−2, 6 ×10−2, 7 ×10−2, 8 ×10−2, 9 ×10−2, 10 ×10−2 and 15 ×10−2 mV/s). The sensor’s sustainability was tested in terms of its cyclic response in longer time periods of one, seven, and thirty days. The electrochemical impedance spectroscopy (EIS) was also analysed, and it showed a number of wide and shallow lines in the high-frequency regions that were used to examine the resistance and conductance of γ-Al2O3QDs/GCE sensor. In addition to this, a real sample analysis was conducted with γ-Al2O3QDs/GCE for the tap water samples collected from three different places. The acquired results are then discussed in detail.
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•The γ-Al2O3QDs were prepared via hydrothermal process and well characterized.•The γ-Al2O3QDs were employed for the sensing against thiourea at varied conc.•Effect of conc., potential, cyclic responses, impedance and real sample analysis were studied.•Impedance of γ-Al2O3QDs/GCE were studied with varied thiourea concentrations.•The discussion related to influence with γ-Al2O3QDs for thiourea was explained.