In-BTC-derived hexagonal In2O3 nanosheets decorated with Au nanoparticles for enhanced NH3-sensing performance at room temperature

Ammonia (NH3) plays a key role in environmental protection and human health. Therefore, selective detection of NH3 at low temperature is of great significance for environmental monitoring and daily life. In this work, hexagonal In2O3 nanosheets with the thickness of about 35 nm are facilely synthesized from the In-BTC precursors. Then, well-dispersed spherical gold (Au) nanoparticles with diameter of about 10 nm are simultaneously decorated on surface of the In2O3 nanosheets. The sensor based on hexagonal Au-In2O3 nanosheets displayed the highest response (Ra/Rg = 21.42) to 20 ppm NH3 gas at room temperature with the fast response/recovery time of 8/18 s. Meanwhile, the sensor exhibited good repeatability stability and high selectivity towards NH3 among other test gases. The excellent room temperature sensing behavior is ascribed to synergistic effect of nanosheets structure, Au nanoparticles-enhanced surface chemisorption of oxygen species, and the Schottky barrier. The synthesized hexagonal Au-In2O3 nanosheets provide a new candidate for exclusive NH3 detection at room temperature.