Introductory chapter: Fundamentals of photocatalysis and electrocatalysis

Within the context of growing energy demand and serious environmental pollution, photocatalysis and electrocatalysis hold great promise for utilizing transient and renewable energy. Thus, they have been intensively investigated over the recent decades. Graphene oxide, with many attractive features, has been widely applied in these areas. In this chapter, first, graphene oxide is briefly introduced with a focus on its history. Besides, the fundamental principles of semiconductor photocatalysis, comprised of thermodynamics and kinetics, are presented. It covers the requirements for ideal photocatalysts and brings together the basic science addressing the design and modification strategy for performance enhancement. Following this, electrocatalysis, especially electrochemical water splitting, including hydrogen evolution reaction and oxygen evolution reaction, is comprehensively overviewed. The measurement criteria in these two reactions are highlighted. Finally, opportunities and challenges for graphene oxide used in photocatalysis and electrocatalysis are described. This chapter provides a foundation for the solid understanding in photocatalysis and electrocatalysis. It intends to inspire research interest in creating innovative graphene oxide–based nanomaterials for photocatalysis and electrocatalysis.