Electronic effect of substituents regulates the photocatalytic activity of PhC2Cu

To examine the electronic effect of substituents on the photocatalytic performance of PhC2Cu, two organometallic photocatalysts with either an F-atom (4F-P) or a CH3-group (4CH3-P) substituent at the phenyl ring para position were prepared by a facile one-step aqueous-phase method. Density functional theory calculations of the three organometallic photocatalysts (4F-P, P and 4CH3-P) revealed the substituent electronic effect on the frontier orbital energies and on the charge density at the Cu+ ion. This study indicates that the introduction of the strongly electron-withdrawing F atom facilitates the effective separation of the photo-generated charge carriers, while the introduction of the electron-donating CH3 group inhibits it. Consequently, the 4F-P photocatalyst exhibits greater photo-degradation activity compared to 4CH3-P and unsubstituted P. This investigation has shown that the introduction of a strongly electron-withdrawing substituent group is an effective strategy to improve the photocatalytic activity.