Modulating the Chromophores of Metal‐Covalent Organic Frameworks for Boosting Low‐Concentration CO<sub>2</sub> Photoreduction
Chong-Jiu Lu, Jihong Zhang, Jian‐Hua Mei, Yun‐Nan Gong, Tong‐Bu Lu, Di‐Chang Zhong
Abstract
Abstract The development of efficient photocatalysts to convert low‐concentration CO 2 into the value‐added chemicals and fuels is particularly interesting yet remains highly challenging. Herein, we designed and synthesized three metal‐covalent organic frameworks (MCOFs) through the Schiff‐base condensation reactions between trinuclear copper complex and different BDP‐based chromophores (BDP = 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene) for visible‐light‐driven reduction of low‐concentration CO 2 (15%) to HCOO − . As a result, MCOF‐ANT containing anthracene (ANT) groups achieves the highest HCOO − production rate of 1658 µmol g −1 h −1 (HCOO − selectivity, ∼100%) in the absence of any additional noble‐metal photosensitizers under a laboratory light source, which is 7.2 and 2.1 times higher than those of MCOF‐Ph and MCOF‐Nap with phenyl (Ph) and naphthalene (Nap) groups, respectively. Furthermore, MCOF‐ANT also exhibits excellent photocatalytic activity for the reduction of low‐concentration CO 2 (15%) to HCOO − under natural sunlight, with a HCOO − production rate of 1239 µmol g −1 h −1 (HCOO − selectivity, ∼100%). Experiments and theoretical calculations reveal that the presence of ANT in MCOF‐ANT is favorable to the visible‐light harvesting and charge separation, as well as the formation of *OCO intermediate, which clearly accounts for its superior catalytic activity.