GdFeO3 Perovskite Oxide Decorated by Group X Heterometal Oxides and Bifunctional Oxygen Electrocatalysis

Bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are necessary in the renewable energy systems. However, the kinetically slow and large energy-demanding procedures of oxygen electrocatalysis make the preparation of bifunctional catalysts difficult. In this work, we report a novel hierarchical GdFeO3 perovskite oxide of a spherelike nanostructure and surface modification with the group X heterometal oxides. The nanostructured GdFeO3 layer behaved as a bifunctional electrocatalyst in the oxygen electrocatalysis of OER and ORR. Moreover, the surface decoration with catalytically active PtOx + Ni/NiO nanoparticles enhanced the electrocatalytic performances substantially. Incorporation of mesoporous PtOx + Ni/NiO nanoparticles into the porous GdFeO3 nanostructure enlarged the electrochemically active surface area and provided the interconnected nanostructures to facilitate the OER/ORR. The nanostructures were visualized by scanning electron microscopy and transmission electron microscopy images, and the surface area and pore size of nanoparticles were analyzed from N-2 adsorption/desorption isotherms. Tafel analysis indicates that surface modification effectively improves the kinetics of oxygen reactions and accordingly increases the electrocatalytic efficiency. Finally, the 2 wt % PtOx + NiO vertical bar GdFeO3 (x = 0, 1, and 2) electrode achieved the enhanced OER performance with an overpotential of 0.19 Vat 10 mA/cm(2) in an alkaline solution and a high turnover frequency of 0.28 s(-1) at eta = 0.5 V. Furthermore, the ORR activity is observed with an onset potential of 0.80 V and a half-wave potential (E-1/2) of 0.40 V versus reversible hydrogen electrode.

Automated summary

A novel hierarchical GdFeO3 perovskite oxide with a spherelike nanostructure and surface modification with group X heterometal oxides was reported in this study. PtOx + Ni/NiO nanoparticles decoration on the nanostructured GdFeO3 layer significantly enhanced the electrocatalytic performances for oxygen electrocatalysis. The incorporation of mesoporous PtOx + Ni/NiO nanoparticles into the porous GdFeO3 nanostructure enlarged the electrochemically active surface area and facilitated OER/ORR.