Enhanced formaldehyde sensing performance of 3D hierarchical porous structure Pt-functionalized NiO via a facile solution combustion synthesis

Abstract A facial solution combustion synthesis is reported for preparing pristine NiO and Pt-functionalized (0.5%, 1%, and 2% Pt loading) NiO. It was found that the obtained products exhibit 3D hierarchical porous structure regardless the Pt-loaded amounts due to the release of gases and the loosely packed NiO particles. Compared with the pristine NiO, the presence of Pt nanoparticles somehow affected the growth behavior of NiO around and embedded on these relatively big NiO nanoparticles in different size. The Pt-functionalized NiO based gas sensor showed lower operating temperature and substantially enhanced responses to formaldehyde, especially 1% Pt-loaded NiO. The 1% Pt-loaded NiO based gas sensor displayed a response value of 9.90 to 2000 ppm formaldehyde at 200 °C, whereas the pristine NiO based gas sensor only showed a response of 3.15 under the same conditions. The plausible explanation for the Pt-functionalized NiO based gas sensors to enhance the gas sensing performance is attributed to the role of Pt on the catalytic oxidation of formaldehyde and the increase of oxygen species quantity.