Electrolysis of water is the decomposition of water (H₂O) into oxygen (O₂) and hydrogen gas (H₂) due to an electric current being passed through the water. In pure water at the negatively charged cathode, a reduction reaction takes place, with electrons (e−) from the cathode being given to hydrogen cations to form hydrogen gas (the half reaction balanced with acid):

     Reduction at cathode: 4H⁺(aq) + 4e^-→ H₂(g)

At the positively charged anode, an oxidation reaction occurs, generating oxygen gas and giving electrons to the anode to complete the circuit:

     Oxidation at anode: 2H₂O(l) → O₂(g) + 4 H⁺(aq) + 4e^-

Carbon is a widely used electrode material for electrolysis of water due to its excellent electric conductivity and electrochemical stability. Carbon material may also subject to degradation under severe electrochemical environments due to radical attack and electrolysis of carbon. The present work is to study the carbon electrode degradation during electrolysis of water with a focus on the surface characterization. The net reaction of electrochemical gasification of carbons during water electrolysis is:

     Net Reaction: C(s) + 2H₂O(l) → CO₂ (g) +2H₂ (g)

Experimental results show that the surface area of carbon cloth electrodes after water electrolysis changes by up to 50 times depends on the working condition.The experimental setup employed in this study is shown in Fig. 1. The effect of various parameters, including operating temperature, voltages and also time durations of water electrolysis, on the carbon surface cloth is investigated to determine the optimum working condition. The analysis was done using H₂SO₄ solution as an electrolyte with 25% concentration and a three-electrode cell was used to measure the capacitance of a single electrode by cyclic charge/discharge (CCD) technique.