Metal-organic frameworks (MOFs) have shown significant potential as photocatalysts. It has been widely assumed that all catalytic active sites within MOFs are functional in photocatalytic reactions but for a three-dimensional MOF, whether the internal catalytic active sites can effectively absorb light and actively contribute to photocatalytic reactions remains to be explored. In this context, we synthesized a two-dimensional nanosheet MOF (2D-MOF) and a three-dimensional bulk MOF (3D-MOF) composed of Zr₆ clusters and tetracarboxylic porphyrin (TCPP) by the approach described in the literature. Re(bpy)(CO)₃Cl (bpy = 2,2′-bipyridine), which has remarkable CO₂ photoreduction ability, was introduced to the two MOFs to create two new photocatalysts 2D-MOF-Re and 3D-MOF-Re, respectively. Photocatalytic CO₂ reduction experiments show that based on the equal number of catalytic active sites, the CO turnover number (TON) of 2D-MOF-Re reaches 27.8 in 6 h, which is 50 times that of 3D-MOF-Re. The result shows that certain catalytic active sites inside the bulk MOF are inactive due to the inability to absorb light. This study illuminates the potential of the dimensional reduction approach in the design of photocatalysts to exploit the capabilities fully.

金属有机框架（MOF）已显示出作为光催化剂的巨大潜力。人们普遍认为MOF内的所有催化活性位点都在光催化反应中发挥作用，但对于三维MOF来说，内部催化活性位点是否能够有效吸收光并积极促进光催化反应仍有待探索。_{在此背景下，我们通过文献中描述的方法合成了由Zr 6}簇和四羧基卟啉（TCPP）组成的二维纳米片MOF（2D-MOF）和三维块状MOF（3D-MOF）。_{将具有显着CO 2}光还原能力的Re(bpy)(CO) ₃ Cl（bpy = 2,2′-联吡啶）引入到两种MOF中，创造出两种新型光催化剂2D-MOF-Re和3D-MOF-Re ， 分别。光催化CO ₂还原实验表明，在同等数量的催化活性位点的基础上，2D-MOF-Re的CO转换数(TON)在6 h内达到27.8，是3D-MOF-Re的50倍。结果表明，块状 MOF 内部的某些催化活性位点由于无法吸收光而处于非活性状态。这项研究阐明了降维方法在光催化剂设计中充分利用其能力的潜力。