Seawater electrolysis represents a potential solution to grid-scale production of carbonneutral
hydrogen energy without reliance on freshwater. However, it is challenged by high
energy costs and detrimental chlorine chemistry in complex chemical environments. Here we
demonstrate chlorine-free hydrogen production by hybrid seawater splitting coupling
hydrazine degradation. It yields hydrogen at a rate of 9.2 mol h–1 gcat
–1 on NiCo/MXenebased
electrodes with a low electricity expense of 2.75 kWh per m3 H2 at 500 mA cm–2 and
48% lower energy equivalent input relative to commercial alkaline water electrolysis.
Chlorine electrochemistry is avoided by low cell voltages without anode protection regardless
Cl– crossover. This electrolyzer meanwhile enables fast hydrazine degradation to ~3 ppb
residual. Self-powered hybrid seawater electrolysis is realized by integrating low-voltage
direct hydrazine fuel cells or solar cells. These findings enable further opportunities for
efficient conversion of ocean resources to hydrogen fuel while removing harmful pollutants.
State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, China
Copyright: doi.org/10.1038/s41467-021-24529-3 © The Author(s) 2021