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 (HfO_x-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 HfO_x 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 HfO_x-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.