Comparative study of sensing behavior of brush coated, electrodeposited and pulsed electrodeposited Pt/GDE based amperometric hydrogen sensors

Method of deposition of Electro-catalyst plays a significant role in the sensing behavior of electrochemical sensors for hydrogen. Amperometric hydrogen sensor operating in fuel cell mode with Nafion as proton conducting electrolyte, platinum as sensing and counter electrodes has been developed. A comparative study of response behavior of hydrogen sensors with brush coated, electrodeposited and pulsed electrodeposited Pt on gas diffusion electrode (GDE) was undertaken in the concentration range of 0-4 % H2/Ar. The crystal structure and microstructure of Pt/GDE were characterized by gracing incidence X-ray diffraction and field emission scanning electron microscopy. In-situ electrochemical impedance spectroscopy was carried out for the sensors with H2/Ar at sensing electrode side. The investigations revealed that Pt/GDE fabricated by pulsed electro-deposition has better sensitivity, response time and stability compared to the brush-coated and electrodeposited Pt/GDE sensors. Improved response of sensor with Pt/GDE fabricated by pulsed electro-deposition is explained based on microstructure of Pt electro-catalyst and interfacial characteristics of electrodes with Nafion.