Compact Yttria-Stabilized Zirconia Based Total NO_x Sensor with a Dual Functional Co₃O₄/NiO Sensing Electrode

Abstract

Yttria-stabilized zirconia (YSZ) based potentiometric gas sensors have been widely utilized for detecting NO x (NO and NO 2 ). Nevertheless, it is still remains challenging issue for YSZ-based sensors to sense total NO x due to the opposite response signals to NO and NO 2 . Herein, we report an efficient strategy to sense total NO x at high temperature (above 300 °C) by designing a dual functional sensing electrode (SE); namely, the SE will simultaneously convert NO (in NO x mixture) to NO 2 and electrocatalyze all of the obtained NO 2 to generate the response signal of total NO x . In comparison with those previously reported total NO x sensors, the proposed total NO x sensor will be featured with a simplified sensor configuration and desirable long-term stability. To confirm the practicability of the proposed strategy, the NO conversion rate of several metal oxides and their composites have been measured and it turns out that the Co 3 O 4 /NiO shows relatively high NO conversion rate. Further study indicates a YSZ-based sensor consisting of (Co 3 O 4 + 20 wt % NiO)-SE and Mn-based RE demonstrates satisfactory performance in detecting total NO x . For instance, analogous response magnitude to NO and NO 2 as well as the mixture of NO/NO 2 (within 35 ppm) is witnessed for the sensor; particularly, the sensor gives acceptable stability and response/recovery rate at the operating temperature of 500 °C within the examined period. In summary, the use of dual functional SE (e.g., Co 3 O 4 /NiO composite SE) indeed addressed those issues of concern in monitoring the level of total NO x and has provided a promising alternative way for designing future high-performance total NO x sensor.

Battery-Sensor Hybrid: A New Gas Sensing Paradigm with Complete Energy Self-Sufficiency

“…One sensing cycle, including a response process in 1000 ppm of NO 2 and a recovery process in air, is shown in Figure a. Upon NO 2 exposure, the device shows a response time of 115 s and a recovery time of 517 s. It is worth noting that sensing signal generation is intrinsic to the device and does not require an external stimulus, for example, a voltage bias, a mechanical power source, or a light illumination, − which is a significant advantage of the proposed self-sufficient device over other close alternatives such as energy harvesters.…”

Machine Learning-Assisted Development of Sensitive Electrode Materials for Mixed Potential-Type NO2Gas Sensors

“…Among the YSZ-based NO 2 gas sensors, NiO was a widely recognized NO 2 -sensitive electrode material with response values around 50 mV for 100 ppm NO 2 , , and the YSZ-based mixed potential NO 2 gas sensors developed in recent years also had response values mostly around 40–70 mV for 100 ppm NO 2 . − The response transient curves of the sensors made using selected sensing electrode materials are shown in Figures and . All sensors exhibited good response recovery characteristics, and the log-linear relationship between the response values and the gas concentrations was well fitted, as shown in Figure , which was consistent with the mixed potential mechanism.…”

Flexible All‐Inorganic Room‐Temperature Chemiresistors Based on Fibrous Ceramic Substrate and Visible‐Light‐Powered Semiconductor Sensing Layer

“…Yttria‐stabilized zirconia (YSZ), as a typical dielectric ceramic substrate, has been regarded as an ideal substrate for constructing semiconductor‐based gas sensors. [ 10 , 11 , 12 ] One prominent advantage of YSZ ceramic is that the hanging bonds originating from the fracture of surface lattice provide a good opportunity for strong bonding with semiconductor sensing materials. [ 13 ] Another superiority is that the high heat resistance (≈1300 °C) makes YSZ ceramic substrate exhibit good compatibility with the thermal treatment of semiconductor‐based gas sensors.…”