Abstract
Seawater is one of the most abundant natural resources on our planet. Electrolysis of seawater is not only a promising approach to produce clean hydrogen energy, but also of great significance to seawater desalination. The implementation of seawater electrolysis requires robust and efficient electrocatalysts that can sustain seawater splitting without chloride corrosion, especially for the anode. Here we report a three-dimensional core-shell metal-nitride catalyst consisting of NiFeN nanoparticles uniformly decorated on NiMoN nanorods supported on Ni foam, which serves as an eminently active and durable oxygen evolution reaction catalyst for alkaline seawater electrolysis. Combined with an efficient hydrogen evolution reaction catalyst of NiMoN nanorods, we have achieved the industrially required current densities of 500 and 1000 mA cm−2 at record low voltages of 1.608 and 1.709 V, respectively, for overall alkaline seawater splitting at 60 °C. This discovery significantly advances the development of seawater electrolysis for large-scale hydrogen production.
Highlights
Seawater is one of the most abundant natural resources on our planet
Kuang et al reported an impressive anode catalyst composed of a nickel-iron hydroxide layer coated on a nickel sulfide layer for active and stable alkaline seawater electrolysis, in which a current density of 400 mA cm−2 was achieved at 1.72 V for two-electrode electrolysis in 6 M KOH + 1.5 M NaCl electrolyte at 80 °C18
Considering the need for catalysts with large surface areas and high-density active sites for seawater splitting, here we report the design and synthesis of a three-dimensional (3D) core-shell Transition metal-nitride (TMN)-based oxygen evolution reaction (OER) electrocatalyst, in which NiFeN nanoparticles are uniformly decorated on NiMoN nanorods supported on porous Ni foam (NiMoN@NiFeN) for exceptional alkaline seawater electrolysis
Summary
Seawater is one of the most abundant natural resources on our planet. Electrolysis of seawater is a promising approach to produce clean hydrogen energy, and of great significance to seawater desalination. Combined with an efficient hydrogen evolution reaction catalyst of NiMoN nanorods, we have achieved the industrially required current densities of 500 and 1000 mA cm−2 at record low voltages of 1.608 and 1.709 V, respectively, for overall alkaline seawater splitting at 60 °C This discovery significantly advances the development of seawater electrolysis for large-scale hydrogen production. For the CER in alkaline media, chlorine would further react with OH− for hypochlorite formation with an onset potential of about 490 mV higher than that of OER, and highly active OER catalysts are demanded to deliver large current densities (500 and 1000 mA cm−2) at overpotentials well below 490 mV to avoid hypochlorite formation[18,19] Another bottleneck hindering the progress of seawater splitting is the formation of insoluble precipitates, such as magnesium hydroxide, on the electrode surface, which may poison the OER and hydrogen evolution reaction (HER) catalysts[19]. This work greatly boosts the science and technology of seawater electrolysis
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