Visible-Light Photocatalytic H<sub>2</sub>O<sub>2</sub> Production Boosted by Frustrated Lewis Pairs in Defected Polymeric Carbon Nitride Nanosheets
Lixia Ma, Yaping Gao, Baoqiang Wei, Luo Huang, Nan Zhang, Qihao Weng, Lu Zhang, Shengzhong Liu, Ruibin Jiang
Abstract
Frustrated Lewis pairs (FLPs) with a unique “push–pull” effect can effectively activate many types of molecules to obtain unanticipated catalytic activity. Herein, FLPs are introduced into polymeric carbon nitride (CN), and their functions in the photocatalytic synthesis of H 2 O 2 are studied. The FLPs in B-doped CN (BCN) are constituted by electron-deficient boron as Lewis acid sites and nitrogen neighbored with cyano groups as Lewis base sites. The formation of FLPs can improve the light absorption ability and the separation of photogenerated carriers. The FLPs afford strong adsorption of O 2, but cannot produce H 2 O 2 directly because the strong activation of oxygen bonds leads to oxygen bond scission during reduction. The FLPs enhance H 2 O 2 production through the effective activation of ethanol (ETOH) by the “push–pull” effect of FLPs. The reduction of O 2 to H 2 O 2 is found through • O 2 – and 1 O 2 species. The photocatalytic H 2 O 2 production rate on BCN can reach 51,008 μM g –1 h –1, which is over 12 times that of pristine CN (4113 μM g –1 h –1 ). This study not only provides an effective approach for enhancing photocatalytic H 2 O 2 production but also deepens the understanding of the role of FLPs in molecule activation.