Graphitic carbon nitride/few-layer graphene heterostructures for enhanced visible-LED photocatalytic hydrogen generation

Hanane Boumeriame (1, 2, 3) , Bruno Machado (1) , Nuno M.M. Moura (4) , P. Serp (5) , Luísa Andrade (2, 6) , Tânia Lopes (2, 6) , Adélio Mendes (2, 6) , Tarik Chafik (3) , Eliana da Silva (1, 2) , Joaquim Faria (1, 2)

1 LSRE-LCM - Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia
2 Universidade do Porto = University of Porto
3 UAE - Abdelmalek Essaadi University [Tétouan] = Université Abdelmalek Essaadi [Tétouan]
4 University of Aveiro
5 LCC - Laboratoire de chimie de coordination
6 LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy

Few-layer graphene (FLG, 2–7 nm thickness) prepared by catalytic chemical vapour deposition (c-CVD), and bulk graphitic carbon nitride (g-C3N4; GCN) were assembled to develop novel 2D/2D xFLGy/GCN heterostructures. The impact of FLG loading and morphology on the activity of GCN has been evaluated towards H2 generation from water splitting under visible-LED irradiation. The heterostructures, characterised by UV–vis DRS, photoluminescence, EPR, Raman, AFM, XRD, XPS, SEM/TEM/STEM and photocurrent, present strong interfacial interaction and show higher photocatalytic activity than pure GCN. The best performing material, 2FLG10/GCN, generated 1274 g−1 h−1 of H2, i.e., 4-times higher than pure GCN. The improved photoactivity was ascribed to a synergistic effect between GCN and FLG, owing to: i) efficient charge separation of photoinduced electron-hole pairs through electron transfer from GCN to FLG, ii) increased surface area, and iii) enhanced visible light absorption. Moreover, the best performing composite presents high stability after four successive cycles with no significant change in its activity.

Mots clés: Graphitic carbon nitride; Few-layer graphene; Interfacial engineering; Hydrogen generation; Charge carrier separation; Photocatalysis

Domaines: Chimie de coordination

Hanane Boumeriame, Bruno Machado, Nuno M.M. Moura, P. Serp, Luísa Andrade, et al.. Graphitic carbon nitride/few-layer graphene heterostructures for enhanced visible-LED photocatalytic hydrogen generation. International Journal of Hydrogen Energy, 2022, 47 (61), pp.25555-25570. ⟨10.1016/j.ijhydene.2022.05.285⟩. ⟨hal-03765847⟩