PNNL

Abstract

Real-time monitoring of combustion products and composition is critical to emission reduction and efficient energy production. The fuel efficiency in power plants and automobile engines can be dramatically improved by monitoring and controlling the combustion environment. However, the development of novel materials for rapid response in chemical sensing and their survivability at extreme environments is a major hindrance for further development in the field while it is critical to ensure environmental safety and new environmental regulations. The stable high temperature metal oxides, such -Ga2O3, exhibit promising oxygen sensing properties in terms of reproducibility, long term stability against interfering gases, and low cross sensitivity to humidity. However, the sensors based on -Ga2O3 and other existing materials lack in response time and stability at elevated temperatures. In this context, we demonstrate an approach to design materials based on Ti-doped Ga2O3, which exhibits excellent stability and rapid response time for oxygen sensing at elevated temperatures. We demonstrate that the nanocrystalline -Ga2O3 films with 5-at% Ti significantly improves the oxygen sensor response time (~20 times) while retaining the stability and repeatability properties of -Ga2O3 in addition to enhancement in the sensitivity. The extreme environment oxygen sensors with a rapid response time and sensitivity represent key advancement for integration into combustion systems for efficient energy conversion and emission reduction.