Ti3C2 nanosheets modified Zr-MOFs with Schottky junction for boosting photocatalytic HER performance

Abstract

As newly-developing non-noble metallic co-catalysts, MXenes have attracted intensive attention as an ideal candidate to promote the photocatalytic H2-production activity. In this study, Ti3C2 nanosheets prepared by intercalation were further attached to porous MOFs (UiO-66-NH2) via one-pot hydrothermal method to form face-to-face intimate contact. The obtained TU10 presented the highest photocatalytic H2-evolution rates in TU series, exceeding that of pure UiO-66-NH2 by approximately 8 times. The speculation revolving about enhanced photocatalytic H2-production performance was proposed as the presence of exposed active sites at the edge of Ti3C2 nanosheets and spatial separation and transfer of charge carriers introduced by the Schottky junction at TU series interface, which accumulated the photo-induced electrons on the surface of Ti3C2 nanosheets and improved its electron-donating ability. The DFT calculations revealed that O-terminated Ti3C2 possessed the most positive Fermi level and the lowest Gibbs free energy (|ΔGH*| = 0.08 ≈ 0). This work may provide new insights for constructing MXenes/MOFs structure based on Schottky junction effect to achieve high photocatalytic H2-production performance.