Enhancement of the photocatalytic hydrogen production with the exfoliation degree of Nb2C cocatalyst

Niobium-carbide, Nb2C, a member of MXene family, has recently drawn considerable attention in photocatalytic H2 production as potential candidate to replace Pt as co-catalyst owing to its favorable physical and chemical properties. The present study explored the influence of the exfoliation level and surface area in suspension on the photocatalytic activity toward hydrogen production of Nb2C as cocatalyst and Eosin Y as photosensitizer. It was found that a Nb2C sample obtained by chemical etching and 4 h sonication (Nb2C-4h) with a high specific surface area in aqueous suspension of 161 m2 ×g−1 measured by the methylene blue method showed the highest hydrogen generation rate (10,290μmolh−1g−1), 3.2 (1 mg m L−1) or 1.7 (0.7 mg m L−1) times higher than that of Nb2C obtained by chemical etching without post-synthetic sonication that has 55 m2 ×g−1 of specific surface area in suspension. The increased performance of Nb2C-4h surpassing many reported photocatalysts was attributed to the beneficial influence of the exposed surface area and level of exfoliation of the MXene sheets. Our results demonstrate the importance of exfoliation to achieve a high surface area in suspension, diminishing the number of layers of the MXene flakes on photocatalytic applications.