Inspection of room temperature hydrogen sensing property of nanostructured polypyrrole/polyaniline hetero-junctions synthesized by one-pot interfacial polymerization

Polypyrrole/Polyaniline (PPy/PAni) hetero-junctions for room temperature operated hydrogen gas sensor are synthesized by simple one-pot interfacial polymerization method. Surface morphological studies done by Scanning Electron Microscope and High Resolution Transmission Electron Microscope confirm the homogeneous size and shape of the PPY/PAni hetero-junction. Amorphous nature of the sensing materials revealed using X-ray Diffraction spectroscopy. Fourier Transform Infrared Spectroscope involved in the analysis of the chemical bonding between the PPy and PAni in the hetero-junction. The bandgap energy of the PPy/PAni hetero-junction is calculated as 3.76 eV using the UV-visible absorption spectra. The sensing electrodes are fabricated by spin coating the PPy/PAni hetero-junction on the Printed Circuit Board (PCB). The electrodes fabricated with PPy/PAni hetero-junction showed selectivity towards hydrogen among oxygen, Liquid Petroleum Gas (LPG), carbon dioxide and ammonia. It also exhibits improved sensor characteristics such as % sensitivity (79.1%), response time (180 s) and recovery time (280 s) towards 50 ppm of hydrogen at mom temperature with 50% of Relative Humidity. The lower limit of detection of the electrode is determined as 5 ppm. The fabricated electrodes exhibits improved stability for the period of 50 days.