Low-Dimensional Nanostructures-Based Branched Networks of Bismuth Sulfide (Bi₂S₃) for Near Room-Temperature NO₂ Sensing

Low-dimensional nanostructures (LDNs) are attracted to gas sensors as they possess more surface area and active sites for gas adsorption. Several dangerous chemicals are released into the atmosphere by various factors, which can lead to a variety of respiratory disorders in humans. To detect the presence of the gas surrounding us, we need high-performance, low-operating-temperature gas sensors. As a very hazardous and damaging gas to the environment, nitrogen dioxide (NO2) is an air pollutant and a primary contributor to photochemical smog and acid rain. Hence, LDNs-based Bi2S3 branched nanorod networks (bNRNs) were prepared in this work using a direct hydrothermal process, and their structural and morphological properties were examined. The sensing investigations revealed that 5% Cr-doped Bi2S3 bNRN has a maximum response of 1232% at 50 °C with a quick response time of 51s toward NO2. The enhanced sensor responses result from the morphology of the branched network, which promotes charge transfer and gas adsorption.