Palladium-decorated vanadium pentoxide as NOx gas sensor

Abstract

Vanadium pentoxide (V2O5) was synthesized hydrothermally by using maleic acid as a surfactant. The Pd nanoparticles were decorated on V2O5 surface with different wt% loading (viz. 0.5 wt%, 1 wt%, 3 wt% and 5 wt% of Pd) by wet impregnation method. Pristine V2O5 and Pd decorated V2O5 samples were investigated for resistive type gas sensor. From sensing results it was observed that 1 wt%Pd@V2O5 showed high response and high selectivity towards NOx gas (mixture of NO and NO2) as compared to other samples towards organic vapours viz SOx, NH3, methanol, ethanol, acetone, trimethylamine, triethylamine, formaldehyde etc. The sensing performance was measured at different temperatures such as room temperature (~30°C), 100°C and 150°C, The optimized sensing performance with maximum response along with shorter response (~1 s) and recovery time (~2 min) was observed for 1 wt%Pd@V2O5 at 150°C. The sensor works in the range of 10 to 1000 ppm gas concentration. The mechanism of sensing and reason for increase in the sensing performance of V2O5 towards NOx gas after Pd loading is discussed. The obtained results are compared with the reported literature and the results found were encouraging.