Methanation of CO2 Using MIL-53-Based Catalysts: Ni/MIL-53–Al2O3 versus Ni/MIL-53

Abstract

MIL-53 and the MIL-53–Al2O3 composite synthesized by a solvothermal procedure, with water as the only solvent besides CrCl3 and benzene-1,4-dicarboxylic acid (BDC), were used as catalytic supports to obtain the novel MIL-53-based catalysts Ni(10 wt.%)/MIL-53 and Ni(10 wt.%)/MIL-53–Al2O3. Ni nanoparticle deposition by an adapted double-solvent method leads to the uniform distribution of metallic particles, both smaller (≤10 nm) and larger ones (10–30 nm). MIL-53–Al2O3 and Ni/MIL-53–Al2O3 show superior thermal stability to MIL-53 and Ni/MIL-53, while MIL-53–Al2O3 samples combine the features of both MIL-53 and alumina in terms of porosity. The investigation of temperature’s effect on the catalytic performance in the methanation process (CO2:H2 = 1:5.2, GHSV = 4650 h−1) revealed that Ni/MIL-53 is more active at temperatures below 300 °C, and Ni/MIL-53–Al2O3 above 300 °C. Both catalysts show maximum CO2 conversion at 350 °C: 75.5% for Ni/MIL-53 (methane selectivity of 93%) and 88.8% for Ni/MIL-53–Al2O3 (methane selectivity of 98%). Stability tests performed at 280 °C prove that Ni/MIL-53–Al2O3 is a possible candidate for the CO2 methanation process due to its high CO2 conversion and CH4 selectivity, corroborated by the preservation of the structure and crystallinity of MIL-53 after prolonged exposure in the reaction medium.

Research Progress on the Preparation of Metal-Organic Frameworks Encapsulated Metal Nanoparticle Composites and Their Catalytic Applications★

“…在这种方法中, 首先将 MOF 分散在疏水性的溶剂中, 然后加入小于或 等于 MOF 孔体积的金属前驱体水溶液, 利用毛细管效 用将其渗透到 MOF 的孔道中, 最后经还原反应实现金 属纳米粒子的封装. 自 Xu 等 [57] 首次开发了双溶剂策略 将 Pt 纳米粒子封装于 MIL-101(Cr)中以来(图 2a), 截至 目前利用此方法已经实现了将一系列单金属纳米粒子 (例如 Pd [58][59][60] 、Ag [61][62] 、Rh [63] 、Ni [64] 、Cu [65] 等)和双金 属纳米粒子(例如 PdAu [66][67] 、PdCu [68] 、AuNi [69] 、RuNi [70] 或 CuCo [71] 等)封装于不同的 MOF 中, 如 NH 2 -UiO-66(Zr) [60] 、 NOTT-300(Al) [61] 、 InOF-1(In) [59] 及 MIL-53(Cr) [64] 等. 此外, Jiang 等 [7] 首先利用双溶剂法将具有 富电子态的 PdCu 纳米粒子封装于磺酸盐功能化的 SO 3 H-UiO-66(Zr) (UiO-S)中, 然后在外部涂覆一层厚度 约为 1 nm 的聚二甲基硅氧烷(PDMS), 获得了 PdCu@ UiO-S@PDMS 材料(图 2b, 2c).…”