Ultrafast charge transfer in metal-free H 2 O 2 photoproduction by anhydride modified g-C 3 N 4 .

As a low-cost, low toxicity and metal-free catalyst with strong light absorption, graphitic carbon nitride (g-C 3 N 4 )-based materials have gained wide attention for efficient H 2 O 2 photocatalysis. However, further investigation regarding the charge transfer process and reaction mechanism of H 2 O 2 photoproduction remains to be completed. In this work, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BTDA) modified g-C 3 N 4 is synthesized through a facile one-step dehydration process, and the H 2 O 2 photoproduction could reach 22.5 μmol within 8 hours. The proposed structure of g-BTDA is confirmed by FTIR, XPS and SEM studies. The transient absorption reveals a 20.88 ps charge transfer process caused by the electron withdrawing ability of the CO group, and a 2-electron oxygen reduction pathway is proposed. Our work represents a new strategy for efficient H 2 O 2 photoproduction using easily acquired materials with future application potential.