Conductometric ppb-level acetone gas sensor based on one-pot synthesized Au @Co3O4 core-shell nanoparticles

Abstract

Detection of acetone is of paramount significance in many fields including self-medical diagnosis, indoor air quality monitoring and other industries. In this study, we assess the acetone sensing capability of novel Au@Co3O4 core-shell nanoparticles (NPs) fabricated using a simple, low temperature (70 °C), in-situ, self-assembly process. The fabricated core-shell nanostructure was sized 70–180 nm, with pomegranate-type morphology and consisted of multi-core Au NPs (5–10 nm in size) inside the Au@Co3O4 core-shell system. P-type Au@Co3O4 core-shell NPs sensor indicated a high response of 27.05–10 ppm acetone at 250 °C. The Au@Co3O4 core-shell NPs sensor also possessed excellent selectivity towards acetone among other interfering gases. The influence of varying levels of relative humidity (RH) on the Au@Co3O4 core-shell NPs were examined, rendering a 60% of response to 2 ppm acetone at 80% RH, and no significant reduction in response at 10–40% RH. The sensor also displayed a low limit of detection (20 ppb), the concentration which is much below the detectable range (1.8 ppm) for a type-I diabetic patient. The Au@Co3O4 core-shell NP sensor developed in this study is considered to open the doors for preparation of other varieties of metal-oxide core-shell systems sensors in a facile approach.