Influence of in-plane and bridging oxygen vacancies of SnO_2 nanostructures on CH_4 sensing at low operating temperatures

TL;DR

This study investigates how in-plane and bridging oxygen vacancies in SnO_2 nanostructures influence low-temperature methane sensing, revealing defect control as key to enhanced sensor performance.

Contribution

It demonstrates the role of specific oxygen vacancies in SnO_2 nanostructures for low-temperature methane detection, with controlled defect engineering improving sensor response.

Findings

Oxygen vacancies enhance methane sensing at 50°C.

Surface defect control improves sensor response.

Photoluminescence correlates defects with sensing performance.

Abstract

Role of 'O' defects in sensing pollutant with nanostructured SnO_2 is not well understood, especially at low temperatures. SnO_2 nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investigation of 'O' defects in SnO_2 nanostructures revealed a strong correlation between shallow donors created by the in-plane and the bridging 'O' vacancies and gas sensing at low temperatures. These SnO_2 nanostructures detected methane (CH_4), a reducing and green house gas at a low temperature of 50 ^oC. Response of CH_4 was found to be strongly dependent on surface defect in comparison to surface to volume ratio. Control over 'O' vacancies during the synthesis of SnO2 nanomaterials, as supported by X-ray photoelectron spectroscopy and subsequent elucidation for low temperature sensing are demonstrated.