Degradation process of Ag/AgCl chloride-sensing electrode in cement extract with low chloride concentration

The accelerated degradation process of Ag/AgCl chloride-sensing electrode was investigated in cement extract by electrochemical behaviors monitoring and surface analysis. The results showed that the potential of Ag/AgCl chloride-sensing electrode was negatively shifted in cement extract, accompanied by the continuous dissolution and exfoliation of AgCl film; however, no Ag2O formed on the electrode surface. The adhesive strength of AgCl to Ag substrate maintained the equilibrium potential of Ag/AgCl chloride-sensing electrode during early stage, but the negative potential shift was pronounced during late stage, which was related to the adsorption of OH- at Ag/AgCl interface, suppressing cathodic reaction on the electrode.