H+/g-C3N4/GO-COOH Composited by Acid-Treated g-C3N4 and Functionalized Graphene Oxide for Efficient Photocatalytic H2 Production

Graphite carbon nitride (g-C3N4) is a potential photocatalyst for decomposing aquatic H2. However, the H2 production activity of g-C3N4 is limited by its small specific surface area and sluggish electron–hole pair separation. To improve the photocatalytic H2 production performance of g-C3N4, the g-C3N4 was treated by acid and then self-assembled with carboxylated graphene oxide (GO-COOH) to obtain H+/g-C3N4/GO-COOH in this work. The acid treatment facilitated the structure change of g-C3N4 and increased its specific surface area. Functionalization of GO resulted in a considerable number of carboxyl groups (−COOH) grafted on the surface of GO. −COOH groups possess a strong electron-withdrawing property and can speed up the H2 production reactions. Meanwhile, the high absorbance of H+/g-C3N4/GO-COOH in the visible light region separated the photogenerated charges efficiently. The H2 production efficiency of H+/g-C3N4/GO-COOH was calculated as1091 μmol·g–1·h–1, approximately 5.42-fold of the efficiency of g-C3N4. This research might bring a fresh opinion in the field of photocatalytic H2 evolution of g-C3N4.