Facile preparation of Au-loaded mesoporous In 2 O 3 nanoparticles with improved ethanol sensing performance.

The in situ monitoring of toxic volatile organic compound gases using metal oxide-based gas sensors is still challenging. Herein, mesoporous In 2 O 3 nanoparticles, assembled using smaller nanoparticles, were synthesized via a facile solvothermal method and used to load Au nanoparticles to prepare mesoporous Au/In 2 O 3 for ethanol detection. The obtained In 2 O 3 and Au/In 2 O 3 were meticulously analysed by XRD, SEM, BET, TEM and XPS techniques. It was revealed that Au nanoparticles were uniformly distributed on mesoporous In 2 O 3 nanoparticles. Notably, the obtained mesoporous 1% Au/In 2 O 3 is highly sensitive to ethanol gas at an optimal working temperature of 180 °C, showing a response of 55 to 50 ppm of ethanol, which is considerably higher compared to that of In 2 O 3 nanoparticles. The significantly enhanced sensitivity results from the electronic and chemical sensitization effects of Au nanoparticles. Moreover, the mesoporous Au/In 2 O 3 nanoparticles also showed eminent selectivity, short response/recovery time, low detection limit, good linear relationship, superb repeatability, and wonderful long-term stability, suggesting that Au/In 2 O 3 nanoparticles have great potential application for in situ monitoring of ethanol gas.