Avaliação eletrocatalítica de nanomateriais com diferentes composições: estudo teórico-experimental

Abstract

This thesis is organized into four chapters, which address advanced strategies in the study of metallic nanoparticles (NPs) applied to the oxygen reduction reaction (ORR) and the electrooxidation of glycerol, with emphasis on the controlled synthesis of nanomaterials. Chapter 1 presents a detailed literature review on the theoretical aspects of the ORR, synthesis strategies for metallic NPs, and the use of these NPs in fuel cells. The reaction mechanisms, as well as the influence of NP composition and morphology on electrocatalytic activity, are discussed, along with the current challenges in developing more efficient and durable catalysts. This review provides the conceptual foundation necessary for the subsequent experimental studies. Chapter 2 describes the experimental methodology employed throughout this work, divided into three parts: bimetallic platinum–molybdenum NPs applied to the ORR; trimetallic NPs composed of platinum, rhodium, and tin applied to the same reaction; and the physicochemical characterization of materials, along with electrochemical and theoretical analyses. The synthesis procedures were optimized to achieve precise control over NP composition, size, and dispersion, enabling the investigation of how these parameters influence catalytic efficiency. Chapter 3 comprises complementary studies involving platinum and rhodium NPs applied to electrooxidation and the controlled synthesis of platinum. The results demonstrate how subtle variations in NP composition and morphology can significantly affect electrocatalytic activity, providing valuable insights for the development of new catalysts. Finally, Chapter 4 presents the general conclusions of the thesis, highlighting the benefits of using metallic NPs in the ORR, including enhanced electron-transfer efficiency and improved stability under operational conditions. The findings indicate that precise control over NP composition and morphology is essential to optimize their electrocatalytic performance, opening promising perspectives for the development of clean and sustainable energy-generation technologies.