Electrochemical NO{sub x} Sensors for Automotive Diesel Exhaust

Conference · Mon Nov 25 04:00:00 EST 2002

OSTI ID:15003123

Martin, L P; Pham, A Q; Glass, R S

New emissions regulations will increase the need for compact, inexpensive sensors for monitoring and control of automotive exhaust gas pollutants. Species of interest include hydrocarbons, carbon monoxide, and oxides of nitrogen (NO{sub x}). The current work is directed towards the development of fast, high sensitivity electrochemical NO{sub x} sensors for automotive diesel applications. We have investigated potentiometric NO sensors with good sensitivity and fast response when operated in 10% O{sub 2}. The sensors consist of yttria-stabilized zirconia substrates attached with NiCr{sub 2}O{sub 4} sensing electrodes and Pt reference electrodes. A composite NiCr{sub 2}O{sub 4}:Rh sensing electrode is shown to give significantly faster response than NiCr{sub 2}O{sub 4} alone. The exact role of the Rh in enhancing the response speed is not clear at present. However, the Rh appears to accumulate at the contacts between the NiCr{sub 2}O{sub 4} particles and may enhance the inter-particle electronic conduction. Ongoing testing of these sensors is being performed to elucidate the sensing mechanisms and to quantify cross sensitivity to, for example, NO{sub 2}.

• Research Organization: Lawrence Livermore National Lab., CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15003123
• Report Number(s): UCRL-JC-151096
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
CARBON MONOXIDE
ELECTRODES
HYDROCARBONS
MONITORING
NITROGEN
OXIDES
POLLUTANTS
REGULATIONS
SENSITIVITY
SUBSTRATES
TESTING
VELOCITY