Experimental and theoretical studies on noble metal decorated tin oxide flower-like nanorods with high ethanol sensing performance

• This study reports for the facile synthesis of Au and Pd-decorated SnO2 hierarchical nanorods.
• The SnO2/noble metal nanocomposites showed high responses towards ethanol at a low temperature of 175 °C.
• Molecular dynamics simulations was used to study the adsorption of ethanol on SnO2(1 1 0).

This study reports a facile solvothermal method for the synthesis of tin oxide (SnO2) flower-like nanorods with dominant (1 1 0) crystal surface, which could be further decorated with varying amounts of noble metals, (gold (Au) and palladium (Pd)) to enhance the gas-sensing properties. Analysis of the gas-sensing results reveal that the decoration of Au and Pd nanoparticles on the surface of the SnO2 nanorods is advantageous in: (i) enhancing the sensitivity towards ethanol (9–15 times); (ii) reducing the response/recovery time (by 15–40 s), and (iii) significantly decreasing the optimum operating temperature (from 250 to 175 °C). Beyond physical experiments, molecular dynamics (MD) method was also conducted to quantify diffusivity, adsorption and reaction capabilities of ethanol on SnO2(1 1 0) plane and to better understand the role of noble metals in enhancing the gas-sensing performance of SnO2. The findings in this study will be useful for future design of metal oxide nanocomposites with specific crystal surface for achieving high performance in surface-governed applications.