Effect of ZnO morphologies on its sensor response and corresponding E-nose performance

•ZnO has been synthesised into three different nanoforms, nanogranules, nanowires, nanoflowers.•Partial specificity towards H2S, NO and the mixture is achieved.•Incorporation of Pt is responsible for the change in the morphology from nanowires to nanogranules.•Regression analysis indicates that a wise selection of combination of sensors gives better prediction accuracy. Understanding the intricate relationship among the gas sensing data produced from different ZnO morphologies is crucial for optimizing electronic nose (e-nose) performance. In the present work, three different morphologies of ZnO namely nanoflowers (NFs), nanogranules (NGs) and nanowires (NWs) have been successfully synthesised and used for e-nose application. Incorporation of Pt in the reaction mixture has been found to be responsible for change in the morphology from NWs to NGs. The partial specificity of the developed sensors towards H2S, NO and their mixture has been used effectively for discrimination of gases. For this, the data repository was created utilizing labelled data as well as feature data. Elaborate study on principal component analysis shows well discrimination of target gas mixture. Importantly, using support vector machine it has been demonstrated that a wise selection of combination of sensors can give a very good accuracy on the prediction of target gas mixture.