This book provides the latest information and methodologies of rotating disk electrode and rotating ring-disk electrode (rde/rrde) and oxygen reduction reaction (orr). It is an ideal reference for undergraduate and graduate students, scientists, and engineers who work in the areas of energy, electrochemistry science and technology, fuel cells, and other electrochemical systems. * presents a comprehensive description, from fundamentals to applications, of catalyzed oxygen reduction reaction and its mechanisms* portrays a complete description of the rde (rotating disc electrode)/rrde (rotating ring-disc electrode) techniques and their use in evaluating orr (oxygen reduction reaction) catalysts* provides working examples along with figures, tables, photos and a comprehensive list of references to help understanding of the principles involved