Quadruple perovskite ruthenate as a highly efficient catalyst for acidic water oxidation

Xianbing Miao,Liang Wu,Shiming Zhou,Lei Shi,Zhenpeng Hu,Lifu Zhang

doi:10.1038/s41467-019-11789-3

Abstract

Development of highly active and durable oxygen-evolving catalysts in acid media is a major challenge to design proton exchange membrane water electrolysis for producing hydrogen. Here, we report a quadruple perovskite oxide CaCu3Ru4O12 as a superior catalyst for acidic water oxidation. This complex oxide exhibits an ultrasmall overpotential of 171 mV at 10 mA cm−2geo, which is much lower than that of the state-of-the-art RuO2. Moreover, compared to RuO2, CaCu3Ru4O12 shows a significant increase in mass activity by more than two orders of magnitude and much better stability. Density functional theory calculations reveal that the quadruple perovskite catalyst has a lower Ru 4d-band center relative to RuO2, which effectively optimizes the binding energy of oxygen intermediates and thereby enhances the catalytic activity.

Highlights

Development of highly active and durable oxygen-evolving catalysts in acid media is a major challenge to design proton exchange membrane water electrolysis for producing hydrogen
The ruthenate oxide CaCu3Ru4O12 belongs to the typical A-site ordered quadruple perovskite compound AA'3B4O12, whose crystal structure can be considered as a 2 × 2 × 2 superstructure of simple cubic perovskite ABO3
Scanning electron microscopy (SEM) image displays that the particle sizes are submicron (Supplementary Fig. 1)

Summary

Introduction

Development of highly active and durable oxygen-evolving catalysts in acid media is a major challenge to design proton exchange membrane water electrolysis for producing hydrogen. Various complex oxides with less precious-metal contents, including perovskite[7,8,9,10] and pyrochlore-type[11,12,13] compounds, were found to exhibit higher intrinsic OER activities relative to the simple binary oxides under acid conditions. This ruthenate catalyst presents an ultralow overpotential of 171 mV at 10 mA cm−2geo in 0.5 M H2SO4 solution, surpassing the most reported robust OER catalysts in acid up to date It achieves large mass activity of 1942 A g−1Ru and specific activity of 22.1 mA cm−2oxide at 1.50 V, which are 170 and 96 times higher than those of the commercial RuO2, respectively.

Methods

Results

Conclusion