;The issue of energy is a major challenge for mankind in the 21st century, and countries have to develop renewable energies as their main energy resources. Among energy resources, hydrogen is considered to be one of most promising energy carriers. How to effectively produce and store," hydrogen" plays an important role in "hydrogen economy".
In this study, water electrolysis is used to produce hydrogen.Two cells, filled with acid and alkaline electrolytes , are separated by proton exchange membrane. The advantage of acido-alkaline electrochemical cell is to reduce the decomposition voltage of water electrolysis. Furthermore, industrial waste liquids, such as sulfuric acid and potassium hydroxide, can be used as electrolytes, and problem of excess chemicals can thus be reduced. In this thesis,the influence of working parameters, such as electrolyte concentration, applied voltage, inter-electrode distance and the number of electrode groups, on the energy efficiency of hydrogen production was discussed
Experimental results show that the decomposition voltage decreases with the increase of electrolyte concentration, especially the decomposition voltage is reduced to 0.7V at concentration of 40wt%. For energy efficiency, the device with multiple electrodes reduces the resistance and has a higher energy efficiency under low applied voltage.A efficiency of 96.74% is presented under the conditions of electrolyte concentration 30wt%,applied voltage 2V, 3 electrode groups in parallel,and inter-electrode distance 6mm. It shows that this acido-alkaline electrochemical cell is highly competitive and can be applied in many commercial applications.
Key words: Water electrolysis；Proton exchange membrane(PEM)；Multi-electrode