Graphene Oxide Wrapped Hollow SnO₂ Sphere for Room Temperature Formaldehyde Sensing: An Insight Through Computational Analysis & Experimental Study

Abstract

This article reports the insights of reduced graphene oxide (RGO) wrapped tin oxide (SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> )-based room temperature (RT) formaldehyde (HCHO) sensor using experimental and theoretical approaches. SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> hollow spheres are primarily responsible for large changes in conductivity due to HCHO adsorption, while RGO layer facilitates in RT detection of these conductometric changes. Sensing measurement data revealed that composite material offers almost 24 times larger response than that of bare RGO with 200 ppm of HCHO. Density functional theory (DFT)-based first principle study has also been carried out to explore the surface interactions between HCHO and composite material for a better understanding of the sensing mechanism. The quantum simulation results suggest that the additional electron transfer originated from the oxidative decomposition of adsorbed HCHO into formate (HCOO <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> ) species is the crucial factor for getting such improved response behavior. Theoretical findings are in good support with the experimental observations. The work has been expected to carry immense significance for paving the way of realizing a simple, low power, and low cost HCHO sensor device suitable for indoor applications.