多孔材料对CO2加氢反应热力学平衡的限制作用为过渡金属催化剂提供了一种具有成本效益的替代方法。在金属有机框架中,金属中心的类型对甲酸产量的提高有比孔径限制尺度更大的影响。M-MOF-74系列能够全面研究不同的金属中心如何影响HCOOH生产,最小化孔径的影响。在这项工作中,分子模拟用于分析HCOOH的吸附和M-MOF-74中的CO2加氢反应,其中M=Ni,Cu,Co,Fe,Mn,Zn。我们结合了经典模拟和密度泛函理论计算,以深入了解控制M-MOF-74金属中心周围HCOOH低覆盖率吸附的机制。金属中心对HCOOH产量的影响通过蒙特卡洛模拟在大规范合奏中进行了评估,在298.15-800K的化学平衡下使用CO2,H2和HCOOH的气相成分,1-60巴。M-MOF-74在HCOOH生产中的性能遵循与HCOOH吸附的吸收和热相同的顺序:Ni>Co>Fe>Mn>Zn>Cu。Ni-MOF-74使HCOOH的摩尔分数增加约在298.15K时与气相相比是105倍,60巴Ni-MOF-74具有比过渡金属催化剂更具经济吸引力的CO2转化的潜力,在与过渡金属催化剂报道的最高甲酸盐水平相当的浓度下实现HCOOH生产,并提供更有价值的分子形式的产物。
The confinement effect of porous materials on the thermodynamical equilibrium of the CO2 hydrogenation reaction presents a cost-effective alternative to transition metal catalysts. In metal-organic frameworks, the type of metal center has a greater impact on the enhancement of formic acid production than the scale of confinement resulting from the pore size. The M-MOF-74 series enables a comprehensive study of how different metal centers affect HCOOH production, minimizing the effect of pore size. In this work, molecular simulations were used to analyze the adsorption of HCOOH and the CO2 hydrogenation reaction in M-MOF-74, where M = Ni, Cu, Co, Fe, Mn, Zn. We combine classical simulations and density functional theory calculations to gain insights into the mechanisms that govern the low coverage adsorption of HCOOH in the surrounding of the metal centers of M-MOF-74. The impact of metal centers on the HCOOH yield was assessed by Monte Carlo simulations in the grand-canonical ensemble, using gas-phase compositions of CO2, H2, and HCOOH at chemical equilibrium at 298.15-800 K, 1-60 bar. The performance of M-MOF-74 in HCOOH production follows the same order as the uptake and the heat of HCOOH adsorption: Ni > Co > Fe > Mn > Zn > Cu. Ni-MOF-74 increases the mole fraction of HCOOH by ca. 105 times compared to the gas phase at 298.15 K, 60 bar. Ni-MOF-74 has the potential to be more economically attractive for CO2 conversion than transition metal catalysts, achieving HCOOH production at concentrations comparable to the highest formate levels reported for transition metal catalysts and offering a more valuable molecular form of the product.