Fig. 6 shows the dynamic responses of the annealing-enhanced Pd–Y thin film toward air and different hydrogen concentrations(from 0.1% to 2% in nitrogen) at room temperature and pressure.The response time, recovery time and response amplitude to each concentration of hydrogen is listed in Table 1. The zero curve tested in air is around 0 V with a fluctuation of less than 0.5 mV. As the con-centration of hydrogen decreased from 2% to 0.1%, the response time increased from 37 s to 45 s and the recovery time decreased from 34 s to 12 s. However, a slight decrease from 37 s to 33 s is observed as the loading concentration of hydrogen decreasing from 2% to 1%. The response value versus hydrogen concentration is