Hydrogen production from simulated seawater by microwave liquid discharge: A new way of green production

Given the current shortage of freshwater resources and the global energy trend is changing to clean and efficient energy, this paper first attempts to use microwave plasma technology for hydrogen production from simulated seawater. The purpose is to build a plasma reactor with unique characteristics of stable operation, which provides the possibility of direct hydrogen production from seawater using plasma technology. To increase hydrogen production and overcome the problem of unstable discharge of pure water, methane (CH4) is introduced into the liquid to realize the gas–liquid two-phase discharge. At different conductivity and CH4 feed flow, the performance of the reactor was evaluated by hydrogen production, hydrogen production energy efficiency, and energy conversing efficiency. The plasma reaction was limited by the optimum conductivity of the solution. At conductivity of 1800 μS/cm, the discharge product was mainly hydrogen, the hydrogen production can reach 2202.3 mL/min, and energy efficiency of hydrogen production and energy conversion efficiency were also increased by 59.6% and 64.8% compared with the pure water experiment. It showed that the change of conductivity significantly affected the plasma chemical reaction. This difference is mainly related to the change of conductivity affecting the number of charges in the solution and and the catalysis of chloride ions. In addition, the optical characteristics and bubble dynamics during the discharge process were also studied to better understand the complex behavior of the plasma reactor. This method proves the huge potential of the reactor for hydrogen production from seawater without a catalyst and provides a new reference for the subsequent hydrogen production industry.