Perovskite oxides as an opportunity to systematically study the Electrooxidation of alcohols and Polyols on materials based on abundant elements: Learning from the experience using pure metals and metallic oxides in (Electro-)catalysis

Abstract

The cost-effective production of green hydrogen is one of the most important challenges for a sustainable energy transition. To decrease the cost in the production of hydrogen through electrolysis, there are several obstacles that must be overcome. For instance, more active and stable anodes made of abundant and cheap materials will contribute to lowering the capital and operational expenditure of the process. It is well-known that the oxidation of water requires high overpotentials, which is the main limitation for the performance of the device. In this context, we believe that substituting the oxidation of water (OER) at the anode of electrolyzers by the oxidation of biomass-derived substances could contribute to the overall process by decreasing the power input of the devices and, in some cases, by producing value-added chemicals. Herein, we re-visited some of the most important fundamental aspects of the (electro-)oxidation of alcohols and polyols on metal-based catalysts, focusing on reaction descriptors. Then, we moved to the (electro-)oxidation of these molecules on metal oxides, re-visiting some of the literature about their application in heterogeneous catalysis and for OER, to get insights about the relation of the structure of the materials and their activity. Due to the lack of fundamental knowledge about the electro-oxidation of alcohols and polyols on metallic oxides and to the vast literature about the use of perovskite oxides for OER, we propose to start systematic studies using perovskite oxides for the electrooxidation of alcohols and polyols. We believe that fundamental studies in this topic would permit the establishment of reaction descriptors, speeding up the searching for suitable materials for this reaction and paving the way for a most cost-effective production of green hydrogen.

Elucidating the validity of electronic characteristics of transition metal perovskites as descriptors bridging electro- and chemocatalysis

“…Further, the hydroxyl ions from the electrolyte are attracted by the oxygen vacancy, retaining the surface structure of the perovskite. 15 Although further research is needed to fully understand the mechanism of GOR on perovskite oxides, studies on CO oxidation suggest that lattice oxygen may also play an active role in oxidizing adsorbed methoxy groups of organic substrates. [35][36][37] Therefore, high oxide ion and vacancy mobility is desirable.…”

“…Recently, perovskite-type TM oxides have also gained increasing attention in the field of organic electrosynthesis, 15 where studies address the lack of fundamental knowledge on the electro-oxidation of alcohols on metal oxides, a potential alternative anode reaction in water splitting. The identification of reaction descriptors could accelerate the search for suitable materials, which is especially needed in the context of low-cost hydrogen production.…”