Unraveling the Roles of Hot Electrons and Cocatalyst toward Broad Spectrum Photocatalytic H_2 Generation of g-C_3N_4 Nanotube

摘要

Exploiting active photocatalysts with broad spectrum light response is a priority target in the field of photocatalysis. Herein, integrating Au and CoO nanoparticles with g-C_3N_4 hollow nanotubes, a promising ternary photocatalyst with wide-light spectrum response (420-650 nm) is designed, in which Au nanoparticles play the dual role of plasmonic electron donor and reduction cocatalyst, while CoO nanoparticles act as oxidation cocatalyst. The optimum H_2 evolution rates of the ternary hybrid reach 238.7 and 4.9 μmol under the irradiation of visible light and monochromic light of 650 nm, respectively. Localized surface plasmon resonance (LSPR) can promote charge-carrier generation in the g-C_3N_4, and the appropriate band alignment between the Au and g-C_3N_4 is favorable for hot electron transfer from Au to g-C_3N_4, which makes this ternary hybrid possess extra hot electrons for water reduction reaction under a wider solar spectrum. Furthermore, Au as a reduction cocatalyst and CoO as an oxidation cocatalyst can effectively impel the charge separation and restrain charge recombination, which is also responsible for the enhanced photocatalytic activity. This work affords a credible strategy for the rational construction of plasmon-assisted photocatalysts for the widerspectrum appliance of solar energy.