High-performance seawater oxidation by a homogeneous multimetallic layered double hydroxide electrocatalyst

Seawater electrolysis is an intriguing technology for sustainable hydrogen production that will not exacerbate the global shortage of freshwater or increase carbon emissions. However, due to the undesirable anodic chlorine evolution reaction and the strong corrosiveness of seawater, this technology is significantly hindered by a lack of robust oxygen evolution reaction (OER) electrocatalysts that exhibit high activity, high selectivity, and good stability. Here, we demonstrate a homogeneous multimetallic catalyst consisting of Ni and Fe coincorporated into CuCo layered double hydroxide (denoted as NiFe-CuCo LDH) that serves as an active and durable OER electrode for high-performance seawater electrolysis. With abundant exposed multimetal sites and well-defined micronanostructures, the NiFe-CuCo LDH catalyst requires overpotentials of only 259, 278, and 283 mV to yield current densities of 100, 300, and 500 mA cm(-2), respectively, in 6 M KOH seawater electrolyte. Moreover, it exhibits very high OER selectivity (Faradaic efficiency of 97.4% for O-2 at 500 mA cm(-2)) and superior durability during operation, working stably under a large current density of 500 mA cm(-2) for up to 500 h in 6 M KOH seawater electrolyte. This multimetallic electrocatalyst is one of the best performing ones among all reported transition-metal-based OER electrocatalysts in alkaline seawater electrolyte, which boosts the development of seawater electrolysis technology.

Automated summary

Seawater electrolysis is a sustainable hydrogen production technology, but it is hindered by a lack of robust oxygen evolution reaction (OER) electrocatalysts. This study presents a multimetallic catalyst that exhibits high activity and durability in seawater electrolysis.