Micro-patterned graphite electrodes: An analysis and optimization of process parameters on hydrogen evolution in water electrolysis

Abstract

The aim of this investigation is to enhance the hydrogen production rate using developed micro-patterned graphite electrode in water electrolysis method. Alkaline sodium hydroxide was used as an electrolyte for enhancing the hydrogen production through the continuous electrolysis process. The Box-Behnken design based four-factor three-level full factorial design was utilized to develop the regression model for the hydrogen production process. The response surface methodology was used to analyze the combined effects of voltage supplied, electrolyte molarity and electrode distance on hydrogen production rate. The maximum hydrogen production rate of 2.3 ml/min was achieved under the optimum conditions such as supply voltage of 2 V, electrolyte molarity of 0.3 M and an electrode distance of 10 cm. The predicted regression equation for the hydrogen production process showed positive effect with the experimental value. Also, the individual parameter on hydrogen yield has been evaluated using ANOVA analysis. The coefficient of determination (R2) of 0.98 showed that the model obtained was highly significant to predict the response accurately with below 2% error. The surface of the graphite microstructure considerably influenced the reaction of the electrolysis on hydrogen evolution rate. The micro-patterned electrode was compared with the planar electrode on the hydrogen production rate at optimum conditions and found a 60% increase in yield.