Water Oxidation Catalysts: The Quest for New Oxide-Based Materials

Christos Mavrokefalos,Greta Patzke

doi:10.3390/inorganics7030029

Abstract

The expected shortage of fossil fuels as well as the accompanying climate change are among the major challenges of the 21st century. A global shift to a sustainable energy landscape is, therefore, of utmost importance. Over the past few years, solar technologies have entered the energy market and have paved the way to replace fossil-based energy sources, in the long term. In particular, electrochemical solar-to-hydrogen technologies have attracted a lot of interest—not only in academia, but also in industry. Solar water splitting (artificial photosynthesis) is one of the most active areas in contemporary materials and catalysis research. The development of low-cost, efficient, and stable water oxidation catalysts (WOCs) remains crucial for artificial photosynthesis applications, because WOCs still represent a major economical and efficient bottleneck. In the following, we summarize recent advances in water oxidation catalysts development, with selected examples from 2016 onwards. This condensed survey demonstrates that the ongoing quest for new materials and informed catalyst design is a dynamic and rapidly developing research area.

Highlights

Solar water splitting, namely the solar-driven splitting of water into molecular hydrogen and oxygen is one of the most promising routes to sustainably solve the issue of energy storage and transport, in the long term [1]
The turnover frequencies (TOFs) value at the overpotential of 0.35 VRHE was calculated at 0.02oxidation s−1
Outstanding of their studyofrevealed that Cr‐substitution resulted in anumber five‐foldof enhancement of the electrochemical performance the catalyst was ascribed to the large oxygen vacancies in the sheets, 3+

Summary

Introduction

Namely the solar-driven splitting of water into molecular hydrogen and oxygen is one of the most promising routes to sustainably solve the issue of energy storage and transport, in the long term [1]. The minimum operational requirement for a water splitting system is the equilibrium voltage of 1.23 V at room temperature [2,3]. In real systems a higher voltage, compared to the thermodynamic value, must be applied to expedite the electrochemical OER. This extra-potential is called overpotential (η), and its minimization is a prerequisite for the development of highly active and cost-effective electrocatalysts.

Results

Discussion

Conclusion