Layered graphitic carbon nitride: nano-heterostructures, photo/electro-chemical performance and trends

As an organic semiconductor, graphitic carbon nitride (g-C3N4) nanosheets have been developed into a highly active photocatalyst for H2O splitting generating H2 under visible light irradiation condition and for reduction of CO2. The photo/electro-chemical performances are dependent on the porous structure, morphology, thickness, and crystallinity of the materials. Construction of g-C3N4 heterojunctions can be vital in enhancing catalytic performances. Instead of focusing on the photocatalysis of g-C3N4 (as in other reviews), this review aims to focus on the photo- and electro-chemical as well as photoluminescence (PL) properties of layered g-C3N4 nanostructured materials with various morphologies. Latest progress in chemical synthesis and engineering of g-C3N4 homo- and hetero-structures are summarized in this review, including exploring (i) the relationship between morphology, composition, crystallinity and thickness of the material; (ii) the construction of homo-/hetero-structures and their band gaps; (iii) photo-/electro-chemical performances; (iv) the possible applications and trends of graphitic carbon nitride materials. The electro-catalytic performance and photoluminescence property of g-C3N4 nanosheets for applications in electrocatalysis and emitting devices are discussed. A variety of versatile properties of g-C3N4 nanomaterials have been constantly discovered recent years. The property evolution and invigorating perspectives on major challenges of layered graphitic carbon nitride are also concluded.