Low emission hydrogen generation through carbon assisted electrolysis

Abstract

The conventional electrolysis process for hydrogen generation offers many advantages such as on-site on-demand generation, pure hydrogen that can be stored for latter use directly in fuel cells, and potential of direct coupling to a renewable source of energy. However, the process is very energy intensive. Therefore, at present hydrogen is produced mainly by Natural Gas reforming and coal gasification at temperatures in the vicinity of 800 °C. This method of hydrogen production involves the steps of reforming/gasification, shift reaction and gas separation at high temperatures to improve hydrogen yield and purity based on its application. This paper investigates the thermodynamic and practical energy benefits of single step water electrolysis process assisted by carbon, where part of the energy can come from the chemical energy of carbon. The process has been demonstrated in a solid state electrolytic cell operating at near room temperature. The paper also discusses the technology status and challenges to achieve high hydrogen generation rates.