Sustainable Water Splitting Using Most Abundant Resources of Iron, Seawater and Renewable Energies

Abstract

Mega H2 production by water electrolysis is essential to replace our current energy carrier mix with a sustainable energy system. However, the implementation of water electrolysis technology worldwide affordable is rather challenging owing to the shortage of fresh water and lack of efficient inexpensive electrodes. Here, we covered the above crucial challenges towards sustainable water electrolysis using the most abundant resources on Earth (iron, seawater and renewable energies). The whole-Fe-based electrodes (Fe foam supported NiFe-X (X=O, P) nanowire arrays) were produced scale-up via a facile soaking-phosphating approach. The optimized NiFe-P||NiFe-O electrode pair (Ni: Fe < 0.015 in molar ratio) only required 1.93 V to deliver large current density of 3000 mA cm−2 for overall seawater splitting at industrial conditions (6 M KOH, 60 oC), and exhibited an excellent long-term stability as well as impressive adaptation to fresh water/tap water/seawater and all kinds of renewable energies.

Keywords: Transition-metal phosphide, Transition-metal oxide/oxyhydroxide, Large current density, Water/seawater splitting, Sustainable hydrogen production