AbstractWe report highly hydrogen selective Pd contacted ZnO nanorods based sensor detecting low concentration even at low operating temperature of 50 °C. The sensor performance was investigated for various gases such as H₂, CH₄, H₂S and CO₂ at different operating temperatures from 50 °C to 175 °C for various gas concentrations ranging from 7 ppm to 10,000 ppm (1%). The sensor is highly efficient as it detects hydrogen even at low concentration of ~7 ppm and at operating temperature of 50 °C. The sensor’s minimum limit of detection and relative response at 175 °C were found 7 ppm with ~38.7% for H₂, 110 ppm with ~6.08% for CH₄, 500 ppm with ~10.06% for H₂S and 1% with ~11.87% for CO₂. Here, Pd exhibits dual characteristics as metal contact and excellent catalyst to hydrogen molecules. The activation energy was calculated for all the gases and found lowest ~3.658 kJ/mol for H₂. Low activation energy accelerates desorption reactions and enhances the sensor’s performance.