Au144 loaded hierarchical In2O3 nanospheres for effective detection of acetone in simulated exhalation

Loading noble metal nanoparticles (NPs) on metal oxides is an effective way to solve the challenge of low sensitivity and poor selectivity of semiconductor sensors in detecting acetone in breath. However, noble metal NPs synthesized by traditional methods suffer from problems including irregular grain shape and uneven grain size, leading to a decrease in gas sensing property. Herein, we loaded atomically precise Au144(SC2H4Ph)60 nanoclusters (NCs) on In2O3 nanospheres to construct Au-loaded In2O3 materials (xAu144/IO) for detecting acetone. The gas sensing properties of xAu144/IO were optimized, and the correlation between acetone responses and the size of Au NPs was studied. Among xAu144/IO, 3Au144/IO has higher responses to acetone with good selectivity, short response/recovery time, low detection limit, and excellent long-term stability. In addition, the dynamic responses to acetone exhibit the size dependence of gold nanoparticles. More attractively, the tests of simulated exhalation indicate that the sensor based on 3Au144/IO can distinguish diabetic patients from healthy people, which is further verified by detecting the breath of a diabetic. The strategy of loading atomically precise nanoclusters adopted in this work provides a new method for the design and preparation of highly selective acetone sensing materials for breath analysis.