CNT serial copper-phenylacetylide to construct high-speed charge transfer/separation channels for effective photocatalytic degradation of PAHs

Abstract

The teratogenicity, carcinogenicity and mutagenicity of polycyclic aromatic hydrocarbons (PAHs) pose a serious threat to the human health. Due to their aromatic ring structure with high bond energy and strong hydrophobicity, the rational design of efficient and stable photocatalysts for the removal of PAHs has become a significant challenge in the field of environmental photocatalysis. Herein, a series of 1D x wt% CNT-P photocatalysts were successfully fabricated for PAH degradation by utilizing highly conductive carbon nanotubes (CNTs) sequentially and tandemly linked with copper-phenylacetylide (PhC₂Cu) units. Among them, the 3 wt% CNT-P photocatalyst achieved almost complete degradation of naphthalene (100 ppm), phenanthrene (10 ppm), and pyrene (10 ppm) at 70 min, 60 min and 50 min, respectively, with degradation efficiencies of 20.9, 24.7 and 49.5 times higher than those of pure copper-phenylacetylide and generally superior to those of the conventional water-soluble photocatalysts. Experiments combined with theoretical calculations indicated that in 3 wt% CNT-P, the high conductivity and high-capacity electron storage provided by CNTs effectively inhibited the radiative recombination of copper-phenylacetylide while avoiding the oxidation of Cu(I) through high-speed electron transfer and timely electron supply. As a consequence, a significant quantity of highly reactive radicals (˙O₂⁻ and ˙OH) was generated on the 3 wt% CNT-P sample, thereby markedly enhancing both the efficiency and stability of the photocatalytic degradation of PAHs.