Enhanced specific surface area of ZIF-8 derived ZnO induced by sulfuric acid modification for high-performance acetone gas sensor

Zeolitic imidazolate framework (ZIF)-8-derived zinc oxide (ZnO) is considered one of the most promising acetone sensing candidate materials for the diagnosis of type-I diabetes. However, very few studies focus on the effect of acidic conditions induced shape change of ZIF-8 derived ZnO on the diffusion and adsorption of acetone gas on the material surface. Here, novel ZIF-8-derived hierarchical ZnO micro-dodecahedra/flower structures (ZnO-DFs) were designed by using sulfuric acid modification. Interestingly, enhanced acetone sensing performance was achieved for the hierarchical ZnO-DFs-2.5 (derived from 2.5 μL sulfuric acid-modified ZIF-8) with a distinguished acetone response (∼120.6 to 100 ppm at 350 °C), which was ∼30 times higher than that of pristine ZnO-DFs. Moreover, the sensors exhibited fast response time (∼0.95 s), low detection limit (∼50 ppb), and superior selectivity. The enhanced performance in hierarchical ZnO-DFs could be ascribed to the improved specific surface area and gas transport channels resulted from the damage of Zn–N bonds in pristine ZIF-8 under acidic conditions. This finding represents an alternative strategy for highly efficient acetone gas sensors and structural-functionalism of MOF-derived metal oxide catalysts.