0 cm2). A Ag/AgCl electrode is the reference electrode, and a platinum electrode is the counter electrode. Electronic pulse signals were provided by an Autolab PGSAT32 instrument (manufacturer, city, state abbrev if US, country) in potential (constant) control mode. The current�Ctime curve of the Pt-doped TiO2NTs preparation is shown in Figure 1. The electrolytes were prepared with pH = 4.4 aqueous H2PtCl6?6H2O (1 g/L) and H3BO3 (20 g/L) at 50 ��C. The deposition time of the sample was set to 90 s to obtain moderately-sized Pt nanoparticles. Linear sweep voltammetry was employed at a current density of 5 mA/cm2 and continuous negative pulse for 10 ms. After each negative pulse, a short positive pulse (current density of 5 mA/cm2, continued for 2 ms) is discharged to the barrier layer capacitance.

Then toff = 100 ms time was used to restore the concentration of metal ions on the deposition surface.Figure 1.Current-time curve for the preparation of Pt-doped TiO2NTs.2.2. Pt-Doped TiO2NTs Sensor ProductionThe TiO2NTs gas sensor is different from traditional gas sensors. TiO2NTs grow directly on the surface of a metal titanium plate and are not coated on a traditional Si substrate or an A12O3 base. Therefore, high-temperature conductive silver glue was applied directly to the Pt-doped TiO2NTs surface to prepare the electrical contacts. The electrodes were closely pasted onto the TiO2NTs. Finally, the wires were connected to measure the surface resistance signal of the sensor. A sketch of the Pt-doped TiO2NTs sensor is shown in Figure 2.Figure 2.Sketch of the Pt-doped TiO2NTs sensor.

2.3. Gas Sensing Test Device and Method for the TiO2NTs SensorFigure 3 presents a schematic of the device utilized to measure the TiO2NTs sensor’s response to the SF6 gas decomposition products. In the experiment, the calibration gases of the SF6 decomposition products were injected through the air intake. The gas flow meter controls and detects the flow rate of the measured gas, and the ceramic heater chip and thermal resistance probe control and measure the surface sensor temperature. The TiO2NTs sensor was then placed in a sealed quartz glass tube. The resistance characteristics of the sensor were determined with an impedance analyzer, and the resistance value of the entire process was recorded. The relative changes in the TiO2NTs sensor’s resistance (i.e.

, sensitivity) was calculated with the formula:R%=(R?R0)/R0��100%where R is the sensor resistance value after injecting the detected gas, and R0 is the stable resistance in N2. The response time of the sensor is the time when the sensor’s resistance reached 90% of the maximum value.Figure 3.Detection Entinostat test device utilized to measure the TiO2NTs sensor’s response to the SF6 decomposition products. (1) Quartz glass tube; (2) thermal resistance probe; (3) carbon NT sensor; (4) ceramic heating slices; (5) vacuum form; (6) vacuum pump; (7) ventilation …