Copper ternary oxides as photocathodes for solar-driven CO2reduction

Abstract

The sun's energy, though free and virtually limitless, is a largely unexploited resource, as its conversion into a storable form presents several technological challenges. A promising way of capturing and storing solar energy is in the form of "solar fuels,"in a process termed artificial photosynthesis. In a photoelectrochemical (PEC) system, the reduction of CO2 to carbon-based fuels is driven on the surface of an illuminated semiconductor electrode. Through the decades, many different classes of semiconducting materials have been studied for this purpose, to varying successes. Because of their cheap and abundant nature, semiconducting transition metal oxides are good candidates to realize this technology in an economic scale and have thus attracted considerable research attention. In this review article, the progress achieved with a specific class of metal oxides, namely, the copper ternary oxides such as copper iron oxide and copper bismuth oxide, for PEC CO2 reduction is examined. Although there have been significant advances in terms of strategies to improve the efficiency and stability of these materials, further studies are warranted to address the many challenges to PEC CO2 reduction and solar fuel production.