Coating of the catalyst on electrode (graphite) dipped into NaHCO3 solution falls off from the surface of the electrode everytime i apply voltage + 0.8 V to -1.5 V vs Ag/AgCl. Why does this happen? I used drop casting technique for coating the electrode. For making the slurry i used 8% active material, 1 % PVDF, 1% carbon black and 150 micro liter of NMP solution and sonicate for 2 hours until it becomes homogeneous slurry. Then dry 8 hours at 80 degree celsius without vacuum after drop casting.