Hierarchically constructed Ag nanowires shelled with ultrathin Co-LDH nanosheets for advanced oxygen evolution reaction

Abstract

It is highly desirable to cut down the electron transfer resistance, improve both site activity and site populations of layered double hydroxides (LDHs) for enhanced electrochemical activity of oxygen evolution reaction (OER). Herein, the hybrid that Co-LDH nanosheets shells grown on Ag nanowires (NWs) cores (Ag@Co-LDH) was constructed and applied as a favorable OER electrocatalyst. The high conductivity of Ag NWs and heterointerface between Ag NWs and Co-LDH gravely accelerate electron transfer. Co-LDH with ultrathin sheet-like structure and abundant grain boundary defects effectively provide lots of active sites. The optimized local environment of Co atoms by Ag dopants and plentiful amorphous regions strongly enhance the intrinsic activity of active site. Therefore, the as-prepared Ag@Co-LDH demonstrates distinguished OER activity with a low overpotential of 217 mV at the current density of 10 mA cm−2, which is superior to most reported advanced OER electrocatalysts and even commercial Ir/C. Moreover, benefiting from the unique structure and stable heterointerface, Ag@Co-LDH also exhibits robust cycling stability and long-term durability proved by accelerated degradation test (ADT) and galvanostatic test, respectively. This finding provides a practical design direction for high-performance LDH-based OER electrocatalysts.