Potentiometric hydrogen sensors based on yttria-stabilized zirconia electrolyte (YSZ) and CdWO 4 interface

A cobalt tungstate compound sensing electrode for hydrogen detection based upon mixed-potential type sensors

“…It has been reported previously that MWO 4 (M ¼ Zn, Mn, Cd) when coupled as the sensing electrodes of the mixed-potential type sensors demonstrated high sensitivity and selectivity to hydrogen. [21][22][23] It points out that the sensing electrode using the transitional metals with partly-empty outermost d shell such as Ni, Co, and Cr in MWO 4 could have better sensitivity and selectivity to lower concentrations of hydrogen.…”

“…The dc polarization curves of the sensors were measured using the three-electrode conguration. 23 The three-electrode conguration designed using Pt as the counter electrode (CE) and reference electrode respectively. A variation of dc voltages from 0 to 200 mV at a step of 10 mV was applied across the CoWO 4 and counter electrode, the current was measured simultaneously by a Keithley system source meter (1 pA to 10 A, Keithley 2612).…”

“…Moreover, the response and recovery time became slower compared to that without water vapor which is similar to the results reported previously. [21][22][23] This might indicate that the co-adsorbed water molecular with oxygen at the TPB could decrease the reaction rate of reaction (3) as well. The sensor would almost recover aer the water vapor was removed from the gas stream as shown in Fig.…”

“…The sensing properties of the CoWO 4 / YSZ/Pt sensor to different concentrations of hydrogen could be explained by the mixed potential theory. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] The sensor response, i.e. the electrical potential difference (EPD) across the two electrodes, is dependent upon the electrochemical redox reactions occurring at each TPB of the electrochemical cell according to:…”

High-Performance Limiting Current Oxygen Sensor Comprised of Highly Active La0.75Sr0.25Cr0.5Mn0.5O3 Electrode

“…Theoretically, when air/fuel (A/F) ratio is fixed at a stoichiometric point, e.g., A/F = 14.7 for gasoline, maximum energy conversion efficiency, and minimum exhaust gases emission are expected [3]. Hence, to minimize these adverse effect derives from the incomplete combustion, the high-performance oxygen sensor is adapted to the combustion system, so that the stoichiometric point of air/fuel (A/F) ratio can be maintained [4,5]. …”