Laser flash photolysis study of Nb 2 O 5 /g-C 3 N 4 heterostructures as efficient photocatalyst for molecular H 2 evolution

Improvements of visible light activity, slow recombination rate, stability, and efficiency are major challenges facing photocatalyst technologies today. Utilizing heterostructures of g-C N (bandgap ∼2.7eV) with Nb O (bandgap ∼3.4eV) as an alternative materials for the first time, we tried to overcome such challenges in this work. Heterostructures of Nb O /g-C N have been synthesized via hydrothermal technique. And then a time-resolved laser flash photolysis of those heterostructures has been analyzed, focusing on seeking how to improve photocatalytic efficiency for molecular hydrogen (H ) evolution. The transient absorption spectra and the lifetime of charge carriers at different wavelengths have been observed for Nb O /g-C N , where g-C N was used for a control. The role of hole scavenger (methanol) has also been investigated for the purpose of boosting charge trapping and H evolution. The long lifetime of Nb O /g-C N heterostructures (6.54165 μs) compared to g-C N (3.1651897 μs) has successfully supported the increased H evolution of 75 mmol/h.g. An enhancement in the rate of H evolution (160 mmol/h.g) in the presence of methanol has been confirmed. This study not only deepens our understanding of the role of scavenger, but also enables a rigorous quantification of the recombination rate crucial for photocatalytic applications in relation with efficient H production.