Heterostructure based on exfoliated graphitic carbon nitride coated by porous carbon for photocatalytic H2 evolution
Daria Baranowska, Klaudia Zielinkiewicz, Tomasz Kędzierski, Ewa Mijowska, Beata Zielińska
Abstract
In this contribution, the heterostructure based on exfoliated graphitic carbon nitride (ex-gCN) coated by a porous carbon layer was fabricated by a simple approach and tested as a photocatalyst for hydrogen evolution under simulated solar light illumination. Bulk-gCN was firstly exfoliated and annealed under a hydrogen atmosphere in carefully selected conditions. The catalyst with the highest photoactivity was fabricated at 400 °C for 4 h. This material exhibited about a 23-fold higher amount of photogenerated hydrogen (18.2 μmol/g) compared to reference ex-gCN (0.8 μmol/g). Boosted photoactivity could be attributed to the (i) highly developed Specific Surface Area leading to more active sites on the surface due to the porous carbon layer, (ii) better transfer, and separation of photogenerated carriers, and (iii) sufficient suppression of the recombination process. Moreover, the mechanism of photocatalytic H2 evolution from water splitting based on a full physicochemical characterization of the studied materials was proposed.