Cerium oxide is a pale yellow-white powder with commercial applications in optics and welding, among other domains. This book explores the synthesis, properties and applications of cerium oxide. Chapter One exposes the different types of cerium oxide nanostructures, with emphasis on the nanotubular structure, the synthesis process, and the influence of using heat treatment. Chapter Two reviews the principal synthetic methodologies used to form cerium oxide and develop its activity. Chapter Three describes the use of metal-doped cerium oxide nanoparticles for the degradation of dyes. Lastly, Chapter Four assesses the catalytic activity of cerium oxide species towards selective catalytic reduction of SO2 with CH4.