Two-step growth of core-shell TiO2/SnO2 nanorod arrays on FTO and its application in gas sensor

The development of gas sensors based on metal oxide semiconductor (MOS) with highly regular mor-phology, highly stable structures, and easy preparation is greatly desired but remains a challenge. Herein, we first prepared a highly regular array of TiO2 nanorods on FTO by a modified in situ hydrothermal method. Then a uniform SnO2 layer grew on the nanorods to form a core-shell nanocomposite by an ion-layer adsorption-reaction process. The TiO2/SnO2 sensors show enhanced gas sensing performance compared with the TiO2 sensors, including higher sensitivity to ethanol, lower working temperature, and better long-term stability. And the highest ethanol response can be obtained when the growth cycle of the SnO2 shell was two times. The gas-sensing mechanism of the TiO2/SnO2 nanocomposites was discussed concerning the unique core-shell structure and a heterojunction between TiO2 and SnO2.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

In this study, a highly regular array of TiO2 nanorods was prepared on FTO by a modified in situ hydrothermal method, followed by the growth of a uniform SnO2 layer on the nanorods to form a core-shell nanocomposite through an ion-layer adsorption-reaction process. The TiO2/SnO2 sensors exhibited improved gas sensing performance compared to TiO2 sensors, including higher sensitivity to ethanol, lower working temperature, and better long-term stability. The highest ethanol response was achieved when the growth cycle of the SnO2 shell was two times. The gas-sensing mechanism of the TiO2/SnO2 nanocomposites was attributed to their unique core-shell structure and the heterojunction between TiO2 and SnO2.