Synergistic effects of zeolite and oxygen vacancies in SnO2 for formaldehyde sensing: Molecular simulation insights & experimental verification

• The adsorption and permeation behavior of formaldehyde and acetone in Na-ZSM-5 zeolite was investigated using molecular simulation. • DFT was used to calculate the adsorption properties of gas molecules on the Na-ZSM-5 cluster model. • A gas-sensitive mechanism of formaldehyde in SnO 2 /Na-ZSM-5 composites was modeled by molecular simulation and DFT calculations. • A sandwich-like zeolite sensor was prepared to verify the accuracy of the simulation results. Computational methods and experimental validation were used and corroborated to investigate the formaldehyde sensing mechanism of SnO 2 /Na-ZSM-5 zeolite composite. The structure-transport properties of fo€rmaldehyde and acetone gas molecules in Na-ZSM-5 were investigated with molecular simulation (MS) and Monte Carlo (MC) techniques. Formaldehyde molecules “co-adsorbed” with water at the polar center of the zeolite framework, some molecules permeated through the zeolite and adsorbed on the surface with hydroxyl groups, enriching the local concentration of formaldehyde. Density functional theory (DFT) calculation showed that formaldehyde has greater adsorption energy and net charge transfer on the zeolite compared with acetone. The oxygen vacancies of SnO 2 in the composite enhanced the sensitivity to formaldehyde. The synergistic effects of the zeolite and the oxygen vacancies of SnO 2 significantly enhanced formaldehyde sensitivity and selectivity for the sensor. The experimental results were in good agreement with the computational simulation conclusions.