CoFe Hydroxide Nanospheres for Enhanced Alkaline Water Splitting and Seawater Oxidation:Anion Doping Effects of Fluorine and Carbonate.

Abstract

Green hydrogen production can be achieved through electrolysis of fresh water or the use of renewable energy to electrolyze seawater. However, due to the low activity and poor stability of oxygen evolution reaction catalysts, direct electrolysis of alkaline seawater faces significant challenges. Herein, The catalyst F-CoFe(OH)-CO3/NF with three-dimensional nanosphere structure was prepared, The introduction of CO3 2- into the intermediate layer of CoFe hydroxide improves the corrosion resistance of alkaline electrolyte and the doping of F- is to design three-dimensional layered nanostructures, increase the active site, and accelerate the diffusion of the electrolyte. By in situ Raman analysis, partial oxidation of CoFe hydroxide to CoFe (oxy)hydroxide as the active center can accelerating the adsorption of oxygen-related intermediates. In 1 M KOH, it requires overpotentials of 210 mV and 251 mV to drive current densities of 10 and 100 mA cm-2, respectively. And it remained stable at the current density of 100 mA cm-2 for 120 h in 1 M KOH. F-CoFe(OH)-CO3/NF can also catalyzes the decomposition of electrolytic seawater. Compared with hydroxide, anion-doped carbonate hydroxide is more efficient and stable in electrolyte solution, which is of great importance for the development of a new stable electrocatalyst for water decomposition.