Photoelectrocatalysis: Fundamentals and Applications presents an in-depth review of the topic for students and researchers working on photoelectrocatalysis-related subjects from pure chemistry to materials and environmental chemistry in order to propose applications and new perspectives. The main advantage of a photoelectrocatalytic process is the mild experimental conditions under which the reactions are carried out, which are often possible at atmospheric pressure and room temperature using cheap and nontoxic solvents (e.g., water), oxidants (e.g., O2 from the air), catalytic materials (e.g., TiO2 on Ti layer), and the potential exploitation of solar light. This book presents the fundamentals and the applications of photoelectrocatalysis, such as hydrogen production from water splitting, the remediation of harmful compounds, and CO2 reduction. Photoelectrocatalytic reactors and light sources, in addition to kinetic aspects, are presented along with an exploration of the relationship between photocatalysis and electrocatalysis. In addition, photocorrosion issues and the application of selective photoelectrocatalytic organic transformations, which is now a growing field of research, are also reported. Finally, the advantages/disadvantages and future perspectives of photoelectrocatalysis are highlighted through the possibility of working at a pilot/industrial scale in environmentally friendly conditions.