Bimetallic Copper–Cerium-Based Metal–Organic Frameworks for Selective Carbon Dioxide Capture

Metal–organic frameworks (MOFs) are highly regarded as valuable adsorbent materials in materials science, particularly in the field of CO 2 capture. While numerous single-metal-based MOFs have demonstrated exceptional CO 2 adsorption capabilities, recent advancements have explored the potential of bimetallic MOFs for enhanced performance. In this study, a CuCe-BTC MOF was synthesized through a straightforward hydrothermal method, and its improved properties, such as high surface area, smaller pore size, and larger pore volume, were compared with those of the bare Ce-BTC. The impact of the Cu/Ce ratio (1:4, 1:2, 1:1, and 3:2) was systematically investigated to understand how adding a second metal influences the CO 2 adsorption performance of the Ce-BTC MOF. Various characterization techniques, including scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and N 2 BET surface area analysis, were employed to assess the physical and chemical properties of the bare Ce-BTC and CuCe-BTC samples. Notably, CuCe-BTC-1:2 exhibited superior surface area (133 m 2 g –1 ), small pore size (3.3 nm), and large pore volume (0.14 cm 3 g –1 ) compared to the monometallic Ce-BTC. Furthermore, CuCe-BTC-1:2 demonstrated a superior CO 2 adsorption capacity (0.74 mmol g –1 ), long-term stability, and good CO 2 /N 2 selectivity. This research provides valuable insights into the design of metal-BTC frameworks and elucidates how introducing a second metal enhances the properties of the monometallic Ce-BTC-MOF, leading to improved CO 2 capture performance.