A review on In2O3 nanostructures for gas sensing applications

Designing of semiconductor metal oxide based gas sensors for detection of toxic analytes describes a facile strategy to address the challenges of environmental contamination and human health. Semiconductor Metal Oxides (SMO) gained the interest of contemporary science for their remarkable characteristics like large surface area, tunable chemical properties, controllable size and good redox behaviour. The excellent properties of metal oxides have been widely explored in environmental remediation, medical diagnostics, food industry, communication sector, defense sector etc., SMO shown good prospects in trace contaminant detection of toxic analytes and are been widely used as sensing materials due to their long term stability, cost-effectiveness, simple fabrication and good sensing response. Among various SMO the Indium Oxide (In2O3) is found to be good sensing material and has attracted significant attention due its stable physiochemical properties, high thermal stability and good redox behaviour. In this review, the prospects of In2O3 in detection of various toxic analytes, its interaction with hazardous gases, chemisorption capability of oxygen, have been discussed. Moreover, the protocols related to synthesis of In2O3 nanostructure and possible routes of enhancement of sensing performance have also been discussed. We also discussed the possible interactions between metal-organic frameworks (MOFs) of In2O3 and their excellent gas-sensing performance in detail. Furthermore, the future prospects of In2O3-based sensors along with consensus recommendations are also discussed.