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, substituting the oxidation of water (OER) at the anode of electrolyzers by the oxidation of biomass-derived substances 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. Consequently, we presented results for LaCoO3, LaFeO3, LaMnO3, and LaNiO3, and propose a mechanism for the electro-oxidation of glycerol based on the formation and reactivity of MOH(O) species. We believe that fundamental and systematic 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.