The Influence of Mof Modification on Oxygen Evolution and Reduction Reaction of Fe-Doped Gdbaco2o5+Δ Perovskite

Abstract

The reconstruction of B-site active phase is an important means to optimize electrocatalytic activity of perovskite. In addition, the type of carbon-based source and its combination way with perovskite can also have an unexpected effect on catalytic activity. Here, we attempted to further enhance the electrocatalytic activity of layered perovskite GdBaCo 2 O 5+δ  (GBCO) by combining two methods. Firstly, Fe doping in the B-site of GBCO is adopted, that is, GdBaCo 2-x Fe x O 5+δ (X= 0.1, 0.2, 0.3, 0.4, 0.5). It was found that Fe doping significantly improved the oxygen evolution reaction (OER) activity of GBCO, and the most active electrocatalyst GBCF40 (X=0.4) showed a low overpotential of 298 mV at 10 mA cm -2 and a small Tafel slope of 79.19 mV dec −1 . Subsequently, MOF ZIF-67 modification was carried out on the surface of GBCF40, named GBCF40@Co-C, which greatly improved its oxygen reduction reaction (ORR) activity. The half-wave potential of the GBCF40@Co-C is as high as 0.850 V, and the half-wave potential only decreases by 5 mV after 5000 cycles of cyclic voltammetry, which is better than Pt/C. Moreover, the electrocatalytic stability of GBCF40@Co-C is superior to pristine GBCF40 and RuO 2 , showing a higher average current density during long-time amperometric test.

Keywords: electrocatalyst, Layered Perovskite GdBaCo2O5+δ, B-site doping, MOF modification, OER/ORR catalytic activities