Nanostructured Cerium Oxide Based Electrocatalysts for Oxygen Reduction Reaction

Abstract

In recent decades, the fast growing of global energy crisis has faced major newlineproblems, including climate change, the depletion of fossil fuels, and the demand for newlineclean and climate-friendly energy sources. Therefore, the research for clean and newlinesustainable energy storage and conversion technologies is a major concern for coming newlineyears. Fuel cells have tremendous potential to meet our growing global energy demands. newlineThe Oxygen reduction reaction (ORR) is recognized as a key reaction in wide range of newlinesustainable energy storage and conversion devices, including alkaline fuel cell. The slow newlinekinetics of the cathodic oxygen reduction reaction (ORR) is the major bottleneck in largescale newlinefuel cells. Pt-based catalysts easily break the O-O bond and adsorption-desorption is newlinevery fast as compared to metal free systems and embedded non-noble metals. Therefore, newlinePt-based catalysts are considered the optimal catalysts for ORR. However, the exorbitant newlineprice, scarcity of earth, and poor stability of Pt-based catalysts prevent widespread newlinecommercialization. Considering these limitations, the design and synthesis of highly newlineactive, stable and low-cost ORR electrocatalyst is a challenging task. Nanostructured newlinemetal oxides like TiO2, ZnO and Fe3O4 have been studied as auspicious alternatives to Pt newlinebased electrocatalysts for ORR. Among these metal oxides, the CeO2 based catalyst plays newlinean essential role in ORR, because of the excellent storage/deoxygenation capacity, rich newlineoxygen vacancies and a swift valence transition between Ce3+ and Ce4+. Up to now, newlineseveral studies have been reported on the use of CeO2 for ORR, but an overall low newlineactivity has been obtained newline