Pd/Pt-Bimetallic-Nanoparticle-Doped In2O3 Hollow Microspheres for Rapid and Sensitive H2S Sensing at Low Temperature.

H2S is a poisonous gas that is widespread in nature and human activities. Its rapid and sensitive detection is essential to prevent it from damaging health. Herein, we report Pd- and Pt-bimetallic-nanoparticle-doped In2O3 hollow microspheres that are synthesized using solvothermal and in situ reduction methods for H2S detection. The structure of as-synthesized 1 at% Pd/Pt-In2O3 comprises porous hollow microspheres assembled from In2O3 nanosheets with Pd and Pt bimetallic nanoparticles loaded on its surface. The response of 1 at% Pd/Pt-In2O3 to 5 ppm H2S is 140 (70 times that of pure In2O3), and the response time is 3 s at a low temperature of 50 °C. In addition, it can detect trace H2S (as low as 50 ppb) and has superior selectivity and an excellent anti-interference ability. These outstanding gas-sensing performances of 1 at% Pd/Pt-In2O3 are attributed to the chemical sensitization of Pt, the electronic sensitization of Pd, and the synergistic effect between them. This work supplements the research of In2O3-based H2S sensors and proves that Pd- and Pt-bimetallic-doped In2O3 can be applied in the detection of H2S.