Real-time monitoring of chlorobenzene gas using an electrochemical gas sensor during mediated electrochemical degradation at room temperature

•Tetracyanonickelate (II)/KOH was fabricated on nickel foam using a dip-coating method.•The novel electrode exhibited a high sensitivity of −1.6 µA ppm−1 cm−2.•The detection range of the electrode was from 1 to 50 ppm with high linearity.•Chlorobenzene gas was monitored during its electrochemical degradation process. The stable molecular structure of chlorobenzene makes it difficult to detect at room temperature. In this study, potassium hydroxide and tetracyanonickelate (II) ([Ni(CN)4]2−) fabricated nickel foam was synthesized using a dip-coating method and monitored the chlorobenzene in the gas phase. The morphology and structure of the as-prepared sample were characterized by X-ray diffraction, field-emission scanning electron microscopy, dispersive energy spectrum, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The gas-sensing test showed that the presence of KOH enhanced the sensing performance of the tetracyanonickelate (II) layer. The KOH/tetracyanonickelate (II)-fabricated nickel foam showed a good response to low chlorobenzene concentrations ranging from 1 to 50 ppm with −0.0016 mA ppm−1 cm−2 sensitivity. In contrast, KOH and the tetracyanonickelate (II) separately fabricated nickel foam showed no response to chlorobenzene. The response time of the sensor was approximately 250 s. The mechanism for the enhanced sensing of tetracyanonickelate (II) was discussed. The sensor stability test confirmed the good stability of the sensor in measuring the chlorobenzene gas concentration. The developed electrochemical gas flow sensor effectively monitored the exit chlorobenzene gas during the electrochemical degradation process; the concentration was calculated using a calibration plot with 98.5% accuracy.