ScholarWorks@성균관대학교

초록

Fabricating ordered micropillar arrays via magnetic assembly of ferromagnetic materials can enhance H2S gas sensors. However, this approach is limited to iron oxide-based ferromagnetic materials, which are unsuitable for H2S gas detection. Cobalt oxide is advantageous for H2S detection despite being intrinsically antiferromagnetic. The key challenge is thus inducing a net ferromagnetic moment in Co3O4 for the fabrication of micropillar arrays, designed to enhance H2S gas sensitivity. Herein, a lithiation-based galvanostatic reduction (LiGr) process synthesizes a material (LiGr-Co) featuring a Co3O4/CoO heterointerface, few-nanometer-scaled particles, and oxygen vacancies. The sub-nanometer-sized particles and oxygen vacancies significantly enhance H2S gas-sensing performance by promoting the formation of short-range order between Co2+ and Co3+ ions. Furthermore, the Co3O4/CoO heterointerface provides the pathway to induce the desired magnetism, as a resulting crystallographic mistilt at the interface generates the required magnetic moment. The aligned LiGr-Co (A-LiGr-Co) sensor, under a magnetic field during the spray coating process, showed improved efficiency in gas adsorption and electron transfer, leading to a reduction of the base resistance and an enhancement of gas-sensing capabilities. A-LiGr-Co demonstrated a high response (R g/R a) of 39.7 at 5 ppm and high selectivity for H2S detection at 150 degrees C.

키워드