Visible-Light Photocatalytic H2O2 Production Boosted by Frustrated Lewis Pairs in Defected Polymeric Carbon Nitride Nanosheets

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 H2O2 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 O2, but cannot produce H2O2 directly because the strong activation of oxygen bonds leads to oxygen bond scission during reduction. The FLPs enhance H2O2 production through the effective activation of ethanol (ETOH) by the "push–pull" effect of FLPs. The reduction of O2 to H2O2 is found through •O2– and 1O2 species. The photocatalytic H2O2 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 H2O2 production but also deepens the understanding of the role of FLPs in molecule activation.