Graphitic carbon nitride (g-C3N4) has unique electronic structure and chemical properties. As a metal-free catalyst

it has shown bright prospects especially in the field of clean and sustainable energy

and thus attracted extensive attention from researchers in the field. This paper reviews the recent progresses in the controllable preparation of g-C3N4 nanomaterials and their applications in energy catalysis including oxygen reduction

photocatalytic water splitting

carbon dioxide reduction and nitrogen photofixation. The crucial issues and future prospects in this research area are also discussed.