Guo Sai-Nan, Wang Dan, Wang Jie-Xin
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China.
Research Center of the Ministry of Education for High, Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
Small Methods. 2024 Oct;8(10):e2301508. doi: 10.1002/smtd.202301508. Epub 2024 Feb 20.
Perovskite nanocrystals are embedded into metal-organic frameworks (MOFs) to create composites with high light absorption coefficients, tunable electronic properties, high specific surface area, and metal atom tunability for enhanced photocatalytic carban dioxide (CO) reduction. However, existing perovskite-MOF structures with a large particle size are achieved based on Pb source adsorption into the pores of MOFs, which can significantly break down the porous structure, thereby resulting in a decreased specific surface area and impacting CO adsorption. Herein, a novel perovskite-MOF structure based on the synthesis of bimetallic Pb-containing MOFs and post-processing to convert Pb to CsPbBr nanocrystals (NCs) is proposed. It is discovered that the additional Pb is not introduced by adsorption, but instead engages in coordination and generates Pb-N. The produced ZIF-8@CsPbBr NCs are ≈40 nm and have an ultra-high specific surface area of 1325.08 mg, and excellent photovoltaic characteristics, which are beneficial for photocatalytic CO reduction. The electronic conversion rate of composites is 450 mol gh, which is more than three times that of pure perovskites. Additionally, the superior reduction capacity is sustained after undergoing four cycles. Density Functional Thoery (DFT) simulations are used to explore the 3D charge density at the ZIF-8@CsPbBr NCs interface to better understand the electrical structure.
钙钛矿纳米晶体被嵌入金属有机框架（MOF）中，以创建具有高光吸收系数、可调电子性质、高比表面积和金属原子可调性的复合材料，用于增强光催化二氧化碳（CO）还原。然而，现有的大粒径钙钛矿-MOF结构是基于Pb源吸附到MOF的孔中而实现的，这会显著破坏多孔结构，从而导致比表面积减小并影响CO吸附。在此，提出了一种基于合成含双金属Pb的MOF并进行后处理以将Pb转化为CsPbBr纳米晶体（NCs）的新型钙钛矿-MOF结构。研究发现，额外的Pb不是通过吸附引入的，而是参与配位并生成Pb-N。所制备的ZIF-8@CsPbBr NCs粒径约为40 nm，具有1325.08 mg的超高比表面积和优异的光伏特性，这有利于光催化CO还原。复合材料的电子转换率为450 μmol g⁻¹ h⁻¹，是纯钙钛矿的三倍多。此外，在经历四个循环后仍保持优异的还原能力。使用密度泛函理论（DFT）模拟来探索ZIF-8@CsPbBr NCs界面处的三维电荷密度，以更好地理解其电子结构。
