The anode in the electrolysis of brine is typically made of carbon.
During the electrolysis of brine (a solution of sodium chloride), positively charged sodium ions move towards the negatively charged anode, where they receive electrons and are converted into neutral sodium atoms. At the same time, negatively charged chloride ions move towards the positively charged cathode, where they lose electrons and are converted into chlorine gas.
The anode material needs to be able to withstand the corrosive environment of the brine and not react with the sodium ions or chlorine gas produced during the electrolysis. Carbon is a commonly used material for the anode because it is stable in this type of environment.