A new direct electrolysis route to the production of green hydrogen requires no pretreatment of seawater and relies on a non-precious-metal catalyst. The technology offers a simplified, less cost-intensive approach to seawater electrolysis relative to available methods.

The system devised by researchers from Tianjin University (China), University of Adelaide (Australia), Kent State University and Nankai University (China) splits natural seawater into oxygen and hydrogen with nearly 100% efficiency. Green hydrogen can be produced electrolytically by using a cobalt oxide-chromium oxide catalyst in a commercial electrolyzer. The process also negates the need for reverse osmosis and other pretreatment steps, and its applicability to seawater should relieve some of the pressure placed on freshwater resources for hydrogen production.

System performance approached that of a commercial proton exchange membrane electrolyzer consuming high-cost platinum/iridium catalysts and fed high-purity water. The stability of the scheme described in Nature Energy was also demonstrated to exceed 100 hours at 500 mA/cm2 and to deliver a current density of 1.0 A/cm2 at 1.87 V and 60° C.

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