p-p heterojunction composite of NiFe2O4 nanoparticles-decorated NiO nanosheets for acetone gas detection.

• The NiFe 2 O 4 /NiO composite nanosheets with different Fe contents have been synthesized. • The composite sensors exhibited enhanced acetone gas sensing performances than pure NiO and NiFe 2 O 4. • The Fe/Ni-24.9 at% sensor reached the highest response value of 56.0 to 200 ppm of acetone. A series of NiFe 2 O 4 /NiO composites composed of NiFe 2 O 4 nanoparticles dispersing on NiO nanosheets were successfully prepared under solvothermal condition using NiO precursor and FeCl 3 ·6H 2 O. Gas-sensing performance assessment demonstrated the formation of composites can improve the properties effectively. The sensor based on sample Fe/Ni-24.9 at% exhibited the optimal gas-sensing performance, showing fast response/recovery, good repeatability and high response of ~23.0 to 50 ppm acetone at 280 °C, which was about 1.8 times and 2.2 times of the pristine NiO and NiFe 2 O 4. The excellent sensing performance can be ascribed to the p-p heterojunction between the NiO and NiFe 2 O 4 , which may decrease the charge carrier concentration in NiO near the heterojunction and bring about larger resistance variation upon the adsorption of target gas. [ABSTRACT FROM AUTHOR]