Metal derivative (MD)/g-C3N4 association in hydrogen production: A study on the fascinating chemistry behind, current trend and future direction

Abstract

Metal derivative/graphitic carbon nitride (g-C3N4) association is found promising in providing sustainable hydrogen production by photocatalytic water splitting process. Number of works reported on the synthesis and application of various metal based g-C3N4 composites are increasing day by day. Mechanism of charge separation varies according to the metal candidate that gets couple with g-C3N4. The present article thus explores the interesting chemistry behind various metal based heterojunction and demonstrates the charge separation route. A thorough investigation has been done on the current research trend in the area. As many metal free g-C3N4 composites are reported nowadays as an alternative to metal derivatives, here compares metallic and metal free derivatives of g-C3N4 based on four critical requirements of an industrial catalyst, ie, activity, stability, cost and toxicity. Challenges and future direction in the area are also discussed with significance. The systematic discussion and schematic illustration of charge transfer process in different heterojunctions with reference to the reported systems, given in the article can definitely contribute to the design and development of more efficient g-C3N4 based heterojunctions in future for hydrogen production application.