Two-dimensional confined electron donor-acceptor co-intercalated inorganic/organic nanocomposites: an effective photocatalyst for dye degradation

Abstract

Photocatalysis is a green catalytic process by utilizing inexhaustible solar light to realize the chemical reaction. Traditionally, most photocatalysts are inorganic semiconductor oxides. Herein, the organic anions, copper phthalocyanine-3,4′,4′′,4′′′-tetrasulfonate (CuPcTS) and 3,4,9,10-perylenetetracarboxylate (PTCB) were selected as guests and co-intercalated into the layered double hydroxides (LDHs) (CuPcTS-PTCB (x%)/LDHs, x was the percentage ratio of PTCB), to obtain the two-dimensional (2D) confined co-intercalated inorganic/organic nanocomposites. The HOMO/LUMO energy levels of the co-intercalated CuPcTS/PTCB anions were matched and coupled as the electron donor and acceptor for the photo-induced electron transfer (PET) process under solar irradiation. The co-intercalated CuPcTS/PTCB anions with similar shape and size were confined and distributed homogenously into the 2D interlayers, which was beneficial for the 2D PET process. The co-intercalated nanocomposites exhibited broad optical absorption in the visible light region, which was in favor of the effective utilization of solar energy for photocatalysis. The equal proportion co-intercalated composite (x = 49.5) with excellent crystallinity and photostability exhibited the best photocatalytic efficiency for oxidation degradation of organic dyes, compared with other proportions and the commercial P25 photocatalyst. Furthermore, the CuPcTS-PTCB (x%)/LDHs exhibited a preferentially faster photodegradation rate for anionic dyes than cationic ones due to the hydrophilic positively-charged LDHs surfaces. In short, this novel 2D confined electron donor/acceptor co-intercalated nanocomposite was a kind of competitive photocatalyst for the degradation of organic contaminants and aromatic toxicants, showing potential applications in environmental protection and pollutant treatment.