Local Proton-Rich Solid Solution Catalyst with a Cluster-in-Cluster Structure for Anti-interference Seawater Splitting.

Abstract

The poor proton coverage of electrocatalysts in neutral hydrogen evolution reaction (HER) and the incapacity to resist alkali hydroxides for seawater electrolysis have resulted in a large kinetics gap from acidic water splitting. Facing this challenge, a cluster-in-cluster solid solution catalyst with a proton-rich microenvironment and anti-interference interface composed of an amorphous hafnium oxide cluster penetrating in crystalline iridium cluster (HfOx-in-Ir SSC), is reported which can achieve superior activity for direct seawater splitting. The structure characterizations, in situ FT-IR and Raman, and theoretical calculations reveal that the HfOx clusters in the Ir cluster endow an interfacial proton-rich microenvironment by increasing the coverage and optimizing the adsorption of *H, thereby achieving a low overpotential of 30 mV in neutral electrolytes. Fascinating, the interfaces of HfOx-in-Ir SSC catalysts present abundant *H and OH* species and simultaneously superior anti-poison to Cl-/ClO- and anti-deposition to Mg(OH)2, eventually achieving an ultra-low overpotential of 117 mV at 10 mA cm-2 and excellent stability in seawater splitting.