Photochemical in‐situ Exfoliation of Metal‒Organic Frameworks for Enhanced Visible‐Light‐Driven CO2 Reduction

Two novel two-dimensional metal-organic frameworks (2D MOF), 2D-M 2 TCPE (M = Co or Ni, TCPE = 1,​1,​2,​2-​tetra(4-​carboxylphenyl)​ethylene), which are composed of staggered (4,4)-grid layers based on paddlewheel-shaped dimers, serve as heterogeneous photocatalysts and achieve efficient reduction of CO 2 to CO. During the visible-light-driven catalysis, these structures undergo in-situ exfoliation to form nanosheets, which exhibit excellent stability and improved catalytic activity. The exfoliated 2D-M 2 TCPE nanosheets display a high CO evolution rate of 4174 μ mol g -1 h -1 and high selectivity of 97.3% for M = Co and Ni, and thus they are superior to most reported MOFs. The performance differences and photocatalytic mechanisms have been studied with theoretical calculations and photoelectric experiments. This work proposes a new insight for the controllable synthesis of effective crystalline photocatalysts based on structural and morphological co-regulation.