Visible/Near-Infrared-Light-Induced H2 Production over g-C3N4 Co-sensitized by Organic Dye and Zinc Phthalocyanine Derivative

Abstract

A new route is carried out to achieve broad spectral responsive photocatalytic H2 production over g-C3N4 co-sensitized by an indole-based D-π-A organic dye (LI-4) and an asymmetric zinc phthalocyanine derivative (Zn-tri-PcNc) with complementary absorption spectra. Experimental results indicate that both LI-4 and Zn-tri-PcNc are efficient photosensitizers of g-C3N4 for H2 production, and their co-sensitized g-C3N4 (LI-4/g-C3N4/Zn-tri-PcNc) exhibits an extremely high H2 production activity (371.4 μmol h–1) under visible/near-infrared (NIR) light (λ ≥ 420 nm) irradiation, which approximates the summation of the H2 production activity of LI-4/g-C3N4 (233.8 μmol h–1) and Zn-tri-PcNc/g-C3N4 (132.3 μmol h–1), although LI-4 and Zn-tri-PcNc can just absorb the light in the range of 400–600 and 600–750 nm, respectively. Moreover, the co-sensitized catalyst shows a broad visible/NIR light responsive range (400–800 nm) with impressively high apparent quantum yields (AQY) of 16.3, 7.7, and 1.75% at 420, 500, and 700 nm monochromatic light irradiation, respectively. The present work gives a new advance toward panchromatic light responsive photocatalytic application by combining the photosensitization of two different dyes with complementary absorption spectra on one kind of semiconductor.