Synthesis of Pyrochlore Oxides Containing Ir and Ru for Efficient Oxygen Evolution Reaction

Abstract

A versatile synthesis method for pyrochlore oxides containing Ir and Ru with lanthanides Pr, Nd, Eu, Gd, Tb, and Ho is herein presented. Based on the systematic synthesis and Rietveld refinement results, the lattice constants were tunable depending on the ionic radius of the lanthanide used. Subsequently, Pr-based pyrochlore oxides containing Ru and Ir in different ratios were fabricated for the oxygen evolution reaction (OER) in alkaline media, and the OER activity of these catalysts increased when the content of Ir and Ru was the same. Thus, the co-substitution of Ir and Ru in pyrochlore oxides is a novel synthesis strategy for electrocatalysts, which provides great potential for the fabrication of other pyrochlore oxides with various architectures and compositions for application in electrocatalysis.

Structural Refinement and Optoelectrical Properties of Nd2Ru2O7 and Gd2Ru2O7 Pyrochlore Oxides for Photovoltaic Applications

“…Theoretical calculations within the framework of the local density approximation, carried out in the work of Castro et al [ 42 ], reveal that the compound GRO is a semiconductor with an activation energy ( E a ) of 0.089 eV. The high conductivity observed in these pyrochlore oxides can facilitate charge transfer for photovoltaic and photocatalytic applications [ 43 ]. Figure 6 illustrates a bipolar resistive switching mechanism, which is less observable in NRO in the dark.…”

Iridium-Based Perovskites as Efficient Oxygen Evolution Reaction Catalysts in Acid Media

“…To reduce the Ir content in the catalysts and increase their efficiency, different approaches are usually adopted. Of these approaches, one can name partial substitution of Ir with cheaper elements by synthesizing mixed oxides, reducing the particle size of the catalyst, or using oxide supports with a high surface area. ,− Mixed oxides have been recognized as possible formulations to reduce the Ir content and to provide improved OER overpotential. − Among them, perovskites are known as the most promising mixed oxides because of their suitable electrochemical properties, high power/energy density, and cyclic durability. ,, …”