Rationally Designed Cyclooctatetrathiophene‐Based Porous Aromatic Frameworks (COTh‐PAFs) for Efficient Photocatalytic Hydrogen Peroxide Production

Constructing stable and efficient photocatalysts for H₂O₂ production is of great importance and is challenging. In this study, the synthesis of three photoactive cyclooctatetrathiophene (COTh)-based porous aromatic frameworks (COTh-PAFs) in an alternating donor-acceptor (D-A) fashion is presented. In combination with a triazine-derived electron acceptor, PAF-363 exhibits high efficiency for the photosynthesis of H₂O₂ with production rates of 11733 μmol g^-1 h^-1(with sacrificial agent) and 3930 μmol g^-1 h^-1 (without sacrificial agent) from water and oxygen under visible light irradiation. Experimental results and theoretical calculations reveal that the charge transfer positions and the O₂ adsorption sites in PAF-363 are both concentrated on COTh fragments, which facilitate the H₂O₂ production through the oxygen reduction reaction (ORR) pathway. This work highlights that the rational design of COTh-PAFs with consideration of D-A direction, charge transfer positions, and O₂ adsorption sites provides a feasible access to efficient H₂O₂ production photocatalysts.