Sensitivity of SnO2 nanoparticles/reduced graphene oxide hybrid to NO2 gas: A DFT study
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Abstract<p>The sensitivity of SnO<sub>2</sub> nanoparticles/reduced graphene oxide hybrid to NO<sub>2</sub> gas is discussed in the present work using density functional theory (DFT). The SnO<sub>2</sub> nanoparticles shapes are taken as pyramids, as proved by experiments. The reduced graphene oxide (rGO) edges have oxygen or oxygen-containing functional groups. However, the upper and lower surfaces of rGO are clean, as expected from the oxide reduction procedure. Results show that SnO<sub>2</sub> particles are connected at the edges of rGO, making a p-n heterojunction with a reduced agglomeration of SnO2 particles and high gas sensitivity. The DFT results are in good agreement with the experimental characterization of both SnO<sub>2</sub> and rGO using energy gap and XPS values. Gibbs free energy, enthalpy, and entropy of the various considered reactions are calculated. Results show that the sensitivity of the rGO/SnO<sub>2 </sub>hybrid to NO<sub>2</sub> gas is the result of the interplay of the dissociation and oxidation reactions of NO<sub>2</sub> gas.</p>
