Enhanced sensitivity of zinc phthalocyanine-based microporous humidity sensors by varying size of electrode gaps

Exploration on Solvatochromic Sensing Probe of Phenol Blue for L‐Lactic Acid Detection: Effective Strategy to Obtain Reliable Capacitive Sensor

“…Therefore, the C value of the PhB‐sensor increases with exposure to the LA solution mainly because of the adsorption of protons to PhB molecules on the surface of the sensing medium, inducing the polarization of PhB/PVC composite‐sensing medium. [ 42,46 ] Based on these results, we can hypothesize that if the adsorption efficiency of the LA molecules to the PhB/PVC composite‐sensing medium is increased, the sensing performances of our PhB‐sensor can be dramatically improved by solving problems such as fast signal saturation and low linearity shown in Figure 2.…”

“…The C values of the PhB‐sensors were measured to be 4.74 ± 0.10 pF in air and 21.9 ± 0.12 pF in DI water, confirming that the C of the PhB sensor increased even when exposed to DI water. This is because of two reasons, one is that the DI water itself interposed between the IDEs and acted as an additional capacitor, and the other is that the high polarity of water molecules induces polarization in the sensing medium, which could be related to increase in C. [ 42 ] The PhB‐sensors exposed to 0.01 m m LA solution showed C variations of 21.3 ± 0.24 pF, almost similar to those of DI water exposure. However, with the increase in concentrations of the LA solutions to 0.1, 1.0, and 5.0 m m , the C values increased to 35.5 ± 0.63, 139.2 ± 2.01, and 214.3 ± 3.86 pF, respectively, which confirmed a somewhat constant trend in C variations.…”

“…As a result, the absorbance of the solution decreases over time, suggesting that the interaction between PhB and protons inhibits the ICT behavior of the PhB molecules. [ 35,42 ] The color change in the solutions when stored at 4 °C for 80 h after mixing LA solutions of various concentrations with 40 µ m PhB solution is shown in Figure S7 (Supporting Information). To confirm whether these changes in the absorbance of UV‐vis spectrum is a phenomenon caused by the chemical reaction (or interaction) between the LA and PhB molecules, Fourier transform infrared (FT‐IR) spectroscopic analyzes were performed after 0, 24, 48, and 72 hrs by preparing the 100 m m LA solutions containing 40 µ m PhB shown in Figure 3e.…”

Identifying Electrocatalytic Activity Sequence of Metal Phthalocyanines for the Hydrogen Peroxide Oxidation Reaction

“…Figure 1e and S4 shows the metal 2p XPS spectra for the MPc/OCB (M = Mn, Fe, Co, Ni, Cu, and Zn) catalysts, which confirms the loading of MPc in these samples. 29,43,44 In the case of the CoPc/OCB catalyst, the main peak in the low energy region has a position of 782.6 eV in Fig. 1e and can be assigned to the Co 2+ oxidation state.…”