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 similar to 4 times greater response and is also more selective to H-2 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 H-2 and chemisorbed oxygen species.