Efficient NADH Regeneration without Electron Mediator toward Enzymatic CO<sub>2</sub> Reduction Enabled by a Lawn-like TP-COFs/Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> (MXene) Photocatalyst
Ping Wei, Jinfeng Dong, Xingyue Gao, Lekai Chang, Zhipeng Huang, Hailong Zheng, Simon Ming‐Yuen Lee, Wen‐Yong Lou, Chao Peng
Abstract
Photocatalytic nicotinamide adenine dinucleotide (NADH) regeneration coupled with enzymatic CO 2 reduction holds significance for global sustainable development. In this work, acrylonitrile-linked covalent organic frameworks (COFs) loaded on NH 2 –Ti 3 C 2 T x (MXene) forms a lawn-like TP-COFs/Ti 3 C 2 T x (TCM) photocatalyst for NADH regeneration. The optimum photocatalyst TCM-15% achieves a 95% NADH regeneration yield within 30 min. More importantly, the TCM-15% obtains 46% NADH regeneration yield without an electron mediator ([Cp*Rh(bpy)(H 2 O)] 2+ ), even higher than that of the pure TP-COFs with an electron mediator (42%). In the presence and absence of an electron mediator, the NADH regeneration TOF values of TCM-15% were 3.69 and 1.42 h –1, respectively, which were 4.05 and 4.90 times higher than those of pure TP-COFs. Subsequently, in the photoenzymatic catalytic cascade system, the formate formation rates reached 2380 and 543 μmol g –1 h –1, with and without an electron mediator, respectively. This work has laid a great foundation for achieving efficient NADH regeneration and cascade enzyme catalysis without an electron mediator.