Effects of Ni addition on the response of La2CuO4 sensing electrode for NO sensor

- The sensing performance of La2CuO4 electrode was improved by Ni addition.
- The formation of La8Cu5.6Ni2.4O20 is crucial to the enhancement of sensing properties.
- The sensor exhibits high sensitivity to NO and insensitivity to O2.

The effects of Ni addition on the response of La2CuO4 sensing electrode for NO sensors were described in this work. Various Ni contents (0, 5, 10, 15, 20 wt.%) were added into La2CuO4 by ball-milling method, respectively, and a new phase La8Cu5.6Ni2.4O20 was found in the Ni added electrodes. The sensor fabricated with 10 wt.% Ni addition exhibited the highest response to NO at 400 °C. The sintering temperature of the sensing electrodes was elevated to 1100 °C, at which temperature the sensor exhibited high sensitivity to NO and insensitivity to O2. The existence of the new phase La8Cu5.6Ni2.4O20 may be the crucial reason for the enhancement of sensing properties. In addition, polarization curves were measured to further demonstrate the electrochemically catalytic activity of the sensing electrodes.