Improved ethanol gas-sensing properties of optimum Fe–ZnO mesoporous nanoparticles

Fe-doped ZnO (Fe–ZnO) mesoporous nanoparticles have been synthesized via a facile hydrothermal method, which utilizes pluronic triblock copolymer polyethylene glycol–polypropylene glycol–polyethylene glycol (PEO-PPO-PEO) as the pore-forming agent. Fe–ZnO composites have an unique porous structure. Their pore sizes increase with Fe-doping concentration and reach a maximum as Fe concentration is 15 at.%; the specific surface area of synthesized mesoporous Fe–ZnO nanoparticles reaches a maximum as the Fe concentration is about 11 at.%. Electron microscopy, vapor pressure isotherm measurements and photoluminescence (PL) were used to characterize synthesized Fe–ZnO composites. Fe–ZnO-based gas sensors exhibit excellent response in detecting ethanol; the sensing response of Fe(11 at.%)–ZnO reaches 319.8, which is significantly higher than most of the ZnO-based gaseous sensors. The improved sensitivity is ascribed to the increase of oxygen-related defects and specific surface area of Fe–ZnO composites.