The PXRD peaks in Figure demonstrate a match with HKUST-1 spectra for Tinj = 50°C -250°C. The peaks are concentrated at lower 2Θ angles indicating the microporous nature of the materials. However, at higher synthesis temperatures T > 250⁰C, additional peaks (2Θ = 35, 40) are observed due to the formation of copper oxide (CuO); these peaks align with previously reported data. Figure shows that the crystallinity of the HKUST-1 remained consistent up to Tinj = 250 °C. However, increasing the maximum local temperature, e.g., Tinj = 350 °C, led to MOFs (or precursors) oxidation-producing CuO. Note that thermogravimetric analysis (TGA) also confirms the destruction of the BTC linker at T~ 340 °C, see Figure . The presence of CuO can significantly impact the physisorption properties, as it may remain within the pores of the framework, leading to a decrease in specific surface area. The morphologies and microstructures of the HKUST-1 were studied using scanning electron microscopy (SEM). Figure shows that, in general, higher temperature conditions yield smaller particle sizes and higher aspect ratios. At Tinj = 150 °C, see Figure (a), MOFs are a mixture of octahedral and rod-like structures in the 2 -15 μm range, which is consistent with previous reports. Exposed to higher temperatures during synthesis, the individual structures tend to clump together, e.g., at Tinj = 250°C both rod-like particles and agglomerates are present, see The samples' specific surface area and porosity were determined by nitrogen adsorption-desorption (Micromeritics ASAP 2020). Before measurement, the samples were activated under consistent conditions. The Barrett-Joyner-Halenda (BJH) method was used to calculate the pore sizes. Figure (a) shows that the samples' BET surface areas range between 380 -1528 m 2 g -1 . A strong correlation was observed between the surface area and the CO2 injection temperature, with the maximum surface area at Tinj = 150 °C. As the synthesis temperature increases beyond that, the BET surface area decreases, which can be attributed to the formation of agglomerates and the decrease in the size of the crystallites, which in turn reduces the available surface area for gas adsorption. The presence of CuO (shown in PXRD, Figure ) at higher synthesis temperatures indicates the MOF structures are damaged; additionally, the CuO could block the pores of the frameworks, reducing the specific surface area. These findings highlight the importance of understanding the mixing and temperature distribution in the reactor. The thermal stability of HKUST-1 in a nitrogen environment is shown in Figure through TGA.