Enhanced Hydrogen Adsorption on Hydrochloric Acid–Activated Cu–BDC Metal Organic Framework: Structural and Performance Analysis

This study investigates the activation, characterization, and hydrogen adsorption properties of pristine and hydrochloric acid-activated Cu-BDC metal-organic frameworks (MOFs). The activation process aimed to enhance the surface area and pore volume, thereby improving hydrogen storage capabilities. Structural and morphological analyses were conducted using various techniques. X-ray diffraction (XRD) revealed a highly crystalline, well-organized framework, with additional peaks in the activated sample indicating phase transitions induced by activation. Fourier-transform infrared (FT-IR) spectroscopy confirmed the presence of functional groups, including -COO and C-H vibrations of aromatic rings, signifying the retention of essential framework components. Scanning electron microscopy (SEM) showcased regular, cubic microcrystals with homogeneously distributed particles. Thermal stability was assessed via thermogravimetric analysis (TGA), demonstrating that the material is thermally robust. Hydrogen adsorption measurements were performed at 300 K, 126 K, and pressures of 8 and 10 bar. The pristine Cu-BDC MOF exhibited a hydrogen uptake of 0.88 wt% at 126 K and 10 bar, which improved to 1.12 wt% upon activation. The enhanced uptake in the activated sample is attributed to the increased surface area and pore volume, providing more adsorption sites for hydrogen molecules. Notably, low-temperature and high-pressure conditions were found to significantly enhance hydrogen storage performance. These findings highlight the potential of functionalized Cu-BDC MOFs as promising candidates for hydrogen storage applications, contributing to advancements in sustainable energy storage technologies. The study aligns with global efforts to meet the DOE targets for efficient hydrogen storage systems.