Synergistic effect of PdO/Au in enhancing CH4 sensitivity of NiO porous nanoflake

Aimed at improving the high operating temperature and low sensitivity in methane sensors, this work proposes the improvement of CH4 sensitivity of metal oxide semiconductor by employing noble metal modification as sensibilization. PdO/Au/NiO porous nanoflake composites were prepared employed Ni(OH)2 nanoflakes as sacrificial templates through an in-situ reduction and thermal treatment process . The CH4 sensing performance results for Au/NiO, PdO/NiO, and PdO/Au/NiO samples demonstrate that the introduction of noble metals not only reduced the optimal operating temperature by 20°C but also significantly enhanced the gas sensitivity of the gas-sensitive elements to CH4. Besides, compared with pure NiO sensor, the sensors based on PdO/Au/NiO exhibited the reduced response-recovery times for CH4. The selectivity results demonstrated the PdO/Au/NiO sensor showed good selectivity for high concentrations of CH4. The improved CH4 sensing performance can be primarily attributed to the high catalytic activity of Au and electron-catalytic sensitization effect of PdO.