Atomically dispersed Au single sites and nanoengineered structural defects enable a high electrocatalytic activity and durability for hydrogen evolution reaction and overall urea electrolysis

Abstract

The development of exceptionally active and stable trifunctional electrocatalysts is essential to facilitate industrial applications of proton exchange membrane electrolyzers. Rare earth catalysts have a wide range of applications in alkaline solution oxidation, but limitations in their stability and activity prevent their further application. In this paper, Au doped CeO2 coated porous Aux/CeO2 (x= 1,2,3) was designed as a three-function electrocatalyst with excellent performance and stability. At 1 M KOH conditions, both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) reactions exhibit excess potentials of 159.6 and 320.8 mV at a current density of 10 mA cm-2. In addition, when incorporated into an Au2/CeO2 (0.05 mmol, HAuCl4•4H2O) microparticles, the catalyst exhibits the potential of 1.42 V(10 mA cm-2) containing 0.33 M urea in 1 M KOH. Remarkably, for hydrogen production driven by urea electrolysis, Au2/CeO2 demonstrated exceptional performance by requiring only a voltage input of 1.63 V. The reducing agent that forms the Au/CeO2 heterojunction modulates the electronic structure of the Au active site and optimizes the adsorption of the intermediate. In addition, the interaction of the Au monolayer with the CeO2 nanosphere effectively prevents excessive oxidation and dissolution of Au, and the porous hollow structure provides additional exposed active sites and facilitates mass transfer.