VOCs gas sensor based on MOFs derived porous Au@Cr2O3-In2O3 nanorods for breath analysis

Breath analysis is a promising disease monitoring approach in medical diagnosis with the advantages of non-invasive, point-of-care testing, and much low cost than traditional medical analysis. Human exhaled contains hundreds of volatile organic compounds (VOCs), and its concentration variations can be used as the characteristic biomarkers for specific diseases. To achieve the trace detection of VOCs, the MOFs derived porous Au@Cr2O3-In2O3 nanorods composite material for isoprene, ethanol, and formaldehyde gas sensing applications was reported. The characterization results show that the special porous nanorods structure is conducive to a high specific surface area (67.3 m(2)/g of Au@Cr2O3-In2O3) and the modification by Cr2O3 and Au improves the oxygen components and smaller the crystallite size. The gas testing results show that the prepared Au@Cr2O3-In2O3 sensor exhibits the reliable detection ability of typical VOCs biomarkers at a ppb-level concentration, while the working temperature is as low as 180 celcius. The responses of Au@Cr2O3-In2O3 sensor as low as 50 ppb for isoprene, 200 ppb for ethanol, and 200 ppb for formaldehyde in the study concentrations. Furthermore, the sensor exhibits superior response over other typical non-VOCs breathing biomarkers (NH3, CO, H-2, and NO2), which shows excellent selectivity as a VOCs detector. The sensor still has a good long-term stability and performs at high humidity. The heterojunction effect (Cr2O3) and electron sensitization (Au) synthetically improve the gas sensing performance of the sensor. Thus, we believe that the prepared porous Au@Cr2O3-In2O3 nanorod is a promising gas sensing material for the breath VOCs gas detection in related diseases diagnosis.