Photocatalytic degradation of benzotriazole through synergy of electron donor–acceptor units and Au clusters in covalent organic frameworks

Abstract

Covalent organic frameworks (COFs) have attracted great attention in photocatalysis, but the high recombination rate of photo-induced electron − hole pairs limits their photocatalytic performance. We report a synergy strategy based on the donor − acceptor (D-A) effect and Au clusters to enable the effective transfer and separation of photogenerated electrons to rationally fabricate visible light driven photocatalyst (MT-COF-Au) for the degradation of benzotriazole (BTA). MT-COF-Au displayed superior photocatalytic activity. The degradation efficiency of BTA was 93 % within 110 min, which was significantly improved 6.7 times than COF. For BTA degradation, O2− played a prominent role based on reactive species trapping experiments. The products of the last stage of the reaction were ketone, imidazole, acetamide, and nitrogen, which were formed via ring opening and isomerization reactions. MT-COF-Au could be reused for at least 5 cycles without significantly deteriorating its catalytic activity. Experiments and theory calculations confirmed the electron transfer mode and photocatalytic mechanism. This work provides new prospects for the design and synthesis of high-efficiency photocatalyst photocatalysts.