Studies of Nonstoichiometry, Transport, and Interface Characteristics of Pr(x)Ce(1-x)O(2-y) with Applications to Gas Sensors with Enhanced Selectivity

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9701699 Tuller Semiconducting gas sensors presently lack sensitivity and selectivity to specific types of gases including hydrocarbons and NOx important for automotive systems. The Crystal Physics and Electroceramics laboratory at M.I.T. and the Ford Research Laboratory have teamed up to explore the praseodymium-cerium- oxygen system that exhibits a number of features attractive for the design of a versatile multi-component chemical sensor. The proposed research will examine the relationships between composition, temperature and partial pressure of oxygen, as well as the nonstoichiometry, phase stability and transport properties (electronic and ionic). Key features to be studied are: (1) control of the n- and p-type character corresponding to the position of the Fermi energy and relevant sensitivity and selectivity to various HC and NOx molecules; (2) the chemical diffusivity important with respect to aging of the "bulk" properties; (3) surface reaction kinetics relevant to selectivity and response times. Fundamental project studies will be carried out at the Massachusetts Institute of Technology; sensor response and characterization studies are to be performed at Ford Research Labs. The participants of this GOALI project view their feedback and exchange on materials, data, models, and concepts essential to the success of this project. The project is jointly funded by the Ceramics Program of the Division of Materials Research and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate. %%% Semiconducting gas sensors presently lack sensitivity and selectivity to specific types of gases including hydrocarbons and nitrogen oxides important for automotive systems. The Crystal Physics and Electroceramics laboratory at M.I.T. and the Ford Research Laboratory have teamed up to explore the praseodymium- cerium-oxygen system that exhibits a number of features attractive for the design of a versatile multi-component chem ical sensor. This collaborative research project is jointly funded by the Ceramics Program of the Division of Materials Research and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate. ***