Self-assembled Pt–CoFe layered double hydroxides for efficient alkaline water/seawater splitting by spontaneous redox synthesis

The development of high-performance, low-cost and large-scale water/seawater splitting bifunctional electrocatalysts still faces huge challenges. Here, we deliver a novel and simple spontaneous redox synthesis strategy to fabricate a self-supported Pt–CoFe(Ⅱ) layered double hydroxide (LDH) electrocatalyst. The three-dimensional porous structure of the catalyst and the synergistic effect of Pt clusters and CoFe hydroxides jointly contribute to its excellent catalytic activity and enhanced chemical stability. Specifically, in 1 M KOH, the overpotentials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) of Pt–CoFe(Ⅱ) LDH at 10 mA cm−2 are 214 mV and 15 mV, respectively. The catalysts are stable for at least 40 h at high current densities of 100 and 500 mA cm−2. Compared with previously reported electrocatalysts, Pt–CoFe(II) LDHs || Pt–CoFe(II) LDHs overall water (seawater) electrolyzers only require 1.634 (1.651) and 1.798 (1.858) V to reach 100 and 500 mA cm−2 in 1 M KOH water (seawater) electrolyte, confirming the superior catalytic activity of the self-supported Pt–CoFe(Ⅱ) layered double hydroxide electrocatalysts. This study provides a novel and simple synthesis strategy to prepare advanced water/seawater splitting electrocatalysts, which is highly relevant for commercial applications.