Kinetics of Nitric Oxide and Oxygen Gases on Porous Y-Stabilized ZrO2-Based Sensors

Abstract

Using impedance spectroscopy the electrical response of sensors with various porous Y-stabilized ZrO 2 (YSZ) microstructures was measured for gas concentrations containing 0-100 ppm NO with 10.5%O 2 at temperatures ranging from 600-700 °C. The impedance response increased substantially as the sensor porosity increased from 46%-50%. Activation energies calculated based on data from the impedance measurements increased in magnitude (97.4-104.9 kJ/mol for 100 ppm NO) with respect to increasing YSZ porosity. Analysis of the oxygen partial pressure dependence of the sensors suggested that dissociative adsorption was the dominant rate limiting. The PWC/DNP theory level was used to investigate the gas-phase energy barrier of the 2NO+O 2 →2NO 2 reaction on a 56-atom YSZ/Au model cluster using Density Functional Theory and Linear Synchronous Transit/Quadratic Synchronous Transit calculations. The reaction path shows oxygen surface reactions that begin with NO association with adsorbed O 2 on a Zr surface site, followed by O 2 dissociative adsorption, atomic oxygen diffusion, and further NO 2 formation. The free energy barrier was calculated to be 181.7 kJ/mol at PWC/DNP. A qualitative comparison with the extrapolated data at 62% ± 2% porosity representing the YSZ model cluster indicates that the calculated barriers are in reasonable agreement with experiments, especially when the RPBE functional is used.

Emerging Multimodel Zirconia Nanosystems for High‐Performance Biomedical Applications

“…Sensors with efficiency, accuracy, and greater sensitivity could be very useful in monitoring air pollution and fulfill future emission requirements. Recently, Killa et al [ 312 ] presented the interpretation of the reactions governing NO x gas sensing by porous stabilized ZrO 2 ‐based sensors. The results showed a strong dependency on sensor porosity, and higher activation energies were obtained for materials with higher porosity.…”

Effect of Al2O3in Porous Zirconia Electrolytes for NO Sensing

“…It has been shown in other studies that NO x sensing was hindered significantly in sensors where charge transfer was the dominant limiting mechanism for the oxygen reaction; whereas, NO x sensing seemed to proceed more readily when dissociative adsorption was the rate determining step for oxygen. 3,6 The Al 2 O 3 addition to PSZ caused to oxygen partial pressure dependence to become more negative, which suggested gas phase diffusion began to have an impact. Other studies have found a P O2 −1 dependence is associated with gas diffusion.…”

“…The 2 wt% Al 2 O 3 addition provided enhance grain boundary conductivity within the PSZ electrolyte, and possibly limited oxygen reactions along the triple phase boundary; thereby, enabling NO reactions to proceed more readily. Impedance spectroscopy measurements of the various PSZ-Al 2 O 3 based NO sensors were collected for different operating conditions in order to interpret the behavior of: 1) the electrical response, 2) interfacial NO reactions, and 3) the NO sensing response due to the addition of Al 2 Porous electrolyte based NO x sensors are under consideration for impedancemetric [1][2][3][4][5][6] and potentiometric 7-9 exhaust gas sensing applications. Enhanced NO x sensitivity has been observed at such sensors, which typically incorporate electrodes with a dense microstructure.…”

“…Porous electrolyte based NO x sensors are under consideration for impedancemetric [1][2][3][4][5][6] and potentiometric [7][8][9] exhaust gas sensing applications. Enhanced NO x sensitivity has been observed at such sensors, which typically incorporate electrodes with a dense microstructure.…”

Synthesis of Nano-Praseodymium Oxide for Cataluminescence Sensing of Acetophenone in Exhaled Breath

“…However, these methods require complicated, bulky and expensive instruments, and their measuring procedures are also relatively tedious [38,39]. Sensors for breath analysis have attract wide attention because of their simple and compact device fabrication, as well as easy operation [40,41]. Examples include a WO 3 -based sensor for diagnosis of diseases [42], carbon nanotube (CNT)-based sensors functionalized with ionic liquids for infectious diseases [43], surface-enhanced Raman scattering sensor based on gold nanoparticles on reduced graphene oxide for gastric cancer [44].…”