Interfacial electronic interaction of atomically dispersed IrClx on ultrathin Co(OH)2/CNTs for efficient electrocatalytic water oxidation

Abstract

The exploration of highly-efficient oxygen evolution reaction (OER) electrocatalyst with well-defined structure to understand specific structure-performance relationship is crucial to meet the requirement of water-splitting. Herein, we firstly used atomically dispersed IrClx to uniformly decorate ultrathin Co(OH)2 nanosheets to dramatically improve electrocatalytic activity. The synthesized IrClx-Co(OH)2 nanosheets/carbon nanotubes (CNTs) exhibits an overpotential of 230 mV to reach 10 mA/cm2, which was much enhanced compared to that of pristine Co(OH)2/CNTs (308 mV) and commercial benchmark IrO2 (309 mV). X-ray absorption fine structure and density functional theory simulations demonstrate strong interfacial interaction between IrClx and Co(OH)2 nanosheets via the Cl-Ir-O and Ir-Cl-Co bond can efficiently boost its electronic conductivity. The accelerated charge transfer promotes the formation of more positively charged O atoms around cobalt centers, which is beneficial for the deprotonation on IrClx-Co(OH)2 and makes the catalyst facilitate OER.