Surface reconfiguration of silver nanoparticle doped cobalt phosphate for enhancing overall water electrocatalysis in alkali

Abstract

The exploitation of bifunctional catalysts with low energy consumption and high energy efficiency is vital for water splitting under alkaline conditions. Cobalt-based phosphate is regarded to be highly promising for water electrolysis. However, its poor electrical conductivity and low number of exposed active sites on the surface hinder the further improvement of electrocatalytic performance. In-situ reconstitution of the surface is an effective strategy to enhance the catalytic activity of transition metal-based materials. Herein, AgCoPi-OH-6h was obtained by etching Ag-doped cobalt-based phosphates (AgCoPi) with strong alkaline solutions. The doping of Ag increases the intrinsic activity of cobalt-based phosphates, and the etching process enlarges the specific surface area which provides more active sites. As a result, AgCoPi-OH-6h shows excellent OER and HER performance, which affords a current density of 10 mA cm-2 at low overpotentials of 259 mV and 56 mV, respectively. Moreover, the catalyst exhibits great electrocatalytic stability for over 50 h under industrial current (1500 mA cm-2) in 6 M KOH solution. This work provides a new strategy for enhancing the alkaline electrocatalytic behavior of cobalt phosphate catalysts for water splitting under industrial conditions.