Ultra-Stable and Highly Sensitive Co Exsolution Material for Gas Sensing Applications

Abstract

Gas sensors can operate with high performance depending on various ways as stability of sensing material to perform in harsh conditions such as high operating temperature, selectivity, and long-term stability. Conventional metal oxide semiconductors can operate at high temperature with display rapid detection and recovery, an outstanding response at the ppm concentration level. In contradiction, at a high temperature generally leads to a reduction in gas response due to the electron depletion layer (EDL) disappears at the grain boundaries. Thus, investigations on searching appropriate sensing materials for high-temperature sensing application requires more momentous effort. The in-situ metal exsolution have engrossed superior thought as an auspicious tactic to formulate in-situ growth of metal nanoparticles for gas sensing technology due to their high thermal and chemical stabilities that prevent the aging effect. Here we investigated the gas sensing properties of Co exsolved nanoparticle during a wide range of growth by controlling reduction temperature. In metal exsolution, demonstrated in Fig. 1a, a catalytically active metal is implanted into crystal lattice of backbone in oxidizing environments, creating solid solution, and is unconfined (exsolved) on the surface of the nanostructure as metal nanoparticles on exposure to a reduction atmosphere. Form our results, we found that Co ex-solution exhibit high gas response of Ra/Rg 135.1 at operating temperature of 350 °C with high selectivity to acetone gas as presented in Fig. 1b. Our findings suggest that the metal exsolved nanoparticles have potential for achieving high gas response, high selectivity and long-term stability for high temperature sensing applicationsFig. 1 (a) Schematic for in-situ metal exsolution, (b) Evolution of La0.43Ca0.37Co0.06Ti0.94O3-d based sensor, gas response at different operating temperatures Figure 1