Scalable Dealloying Route to Mesoporous Ternary CoNiFe Layered Double Hydroxides for Efficient Oxygen Evolution

The mass production of clean hydrogen fuels via (photo)electrochemical water splitting calls for highly efficient, cost-effective, and eco-friendly catalysts. Herein, a facile and scalable strategy, namely, dealloying, is advanced to fabricate mesoporous ternary layered double hydroxides (LDHs) containing Co, Ni, and Fe for highly efficient oxygen evolution and overall water splitting, based upon elaborate design of precursors and accurate control of the dealloying process. The Co1Ni2Fe1-LDH exhibits remarkable catalytic properties toward oxygen evolution reaction in 1 M KOH, for instance low overpotentials (only requires 240.4 mV on glass carbon electrode, and 228.5 mV on Ni foam to drive 10 mA cm(-2)), a small Tafel slope (38.6 mV dec(-1)), as well as excellent stability (lasts 45 h for 10 mA cm(-2) without deactivation). Surprisingly, a symmetric alkaline electrolyzer constructed with Co1Ni2Fe1-LDH serving as the catalyst for both cathode and anode requires only 1.65 V to drive 10 mA cm(-2). The distinguished features of the catalysts lie in the combined effects of the unique LDH structure with large interlayer spaces, the 3D porous structure, and the synergistic interplay of the metal species, concurrently contributing to the fully exposed active sites, accelerated electrolyte penetration and charge/ion transfer, as well as the well-promoted reaction kinetics. The consolidation of the electrocatalytic merits and the facile, economical fabrication route endows the ternary CoNiFe-LDHs as promising catalysts for the generation of renewable energy resources.