Enhanced H₂ gas sensing properties of Au@In₂O₃ core-shell hybrid metal-semiconductor heteronanostructures

The interest in hybrid nanoparticles (NPs) arises from their combined and often synergetic properties exceeding the functionality of the individual components. Herein, a general, environmentally friendly, and facile hydrothermal approach to synthesizing the metal-semiconductor, Au@In₂O₃ core-shell heteronanostructures, is described. These Au@In₂O₃ core-shell NPs are used as chemiresistive gas sensors for the detection of hydrogen gas in air. The sensor device based on Au@In₂O₃ core-shell NPs showed ∼4 times greater response and is also more selective to H₂ gas compared to the In₂O₃ NPs sensor device. The enhanced activity can be attributed to the catalytic effect of Au, and synergistic interactions between the Au and In₂O₃ NPs formed in the core-shell heteronanostructures in such a way that favors the efficient electron transfer at the interface. The hydrogen sensing behavior is dependent on the redox reaction between the H₂ and chemisorbed oxygen species.