Mechanism of enhanced H2S sensor ability based on emerging Li0.5La0.5TiO3-SnO2 core-shell structure

Abstract The Li0.5La0.5TiO3 (LLTO) is a new sensing material demonstrating ultrafast response to H2S within one second. To further enhance the sensitivity, a LLTO-SnO2 core-shell structure was constructed by the assembly of thin SnO2 nanoflakes on the porous hollow LLTO spheres. The absorption and reaction activity of oxygen on the surface as well as the electron transfer processes were modified and discussed in detail. The formation of oxygen vacancy improves the onset potential of oxygen reduction from 0.61 V to 0.75 V. The effective separation of electrons across the interface helps to take advantage of high response property of SnO2. The response value was improved by 4.5 times than that of pristine LLTO with sub-second response time and excellent stability.