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In this study, porous silicon (PSi) was prepared and tested as an extended gate field-effect transistor (EGFET) for pH sensing. The prepared PSi has pore sizes in the range of 500 to 750 nm with a depth of approximately 42 µm. The results of testing PSi for hydrogen ion sensing in different pH buffer solutions reveal that the PSi has a sensitivity value of 66 mV/pH that is considered a super Nernstian value. The sensor considers stability to be in the pH range of 2 to 12. The hysteresis values of the prepared PSi sensor were approximately 8.2 and 10.5 mV in the low and high pH loop, respectively. The result of this study reveals a promising application of PSi in the field for detecting hydrogen ions in different solutions.

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Zinc oxide (ZnO) nanorods (NRs) have been synthesized via the hydrothermal process. The NRs were grown over a conductive glass substrate. A non-enzymatic electrochemical sensor for hydrogen peroxide (H 2 O 2 ), based on the prepared ZnO NRs, was examined through the use of current-voltage measurements. The measured currents, as a function of H 2 O 2 concentrations ranging from 10 µM to 700 µM, revealed two distinct behaviours and good performance, with a lower detection limit (LOD) of 42 µM for the low range of H 2 O 2 concentrations (first region), and a LOD of 143.5 µM for the higher range of H 2 O 2 concentrations (second region). The prepared ZnO NRs show excellent electrocatalytic activity. This enables a measurable and stable output current. The results were correlated with the oxidation process of the H 2 O 2 and revealed a good performance for the ZnO NR non-enzymatic H 2 O 2 sensor.

Macroporous silicon was prepared through an anodization process; the prepared samples showed an average pore size ranging from 4 to 6 microns, and the depth of the pores in the silicon wafer was approximately 80 microns. The prepared samples were tested for hydrogen peroxide (H2O2) concentrations, which can be used for industrial and environmental sensing applications. The selected H2O2 concentration covered a wide range from 10 to 5000 μM. The tested samples showed a linear response through the tested H2O2 concentrations with a sensitivity of 0.55 μA μM–1∙cm–2 and lower detection limits of 4.35 μM at an operating voltage of 5 V. Furthermore, the electrode exhibited a rapid response with a response time of ca. two seconds. Furthermore, the prepared sensor showed a reasonable stability over a one-month time period.