Sonochemical synthesis of novel decorated graphene nanosheets with amine functional Cu-terephthalate MOF for hydrogen adsorption: Effect of ultrasound and graphene content

Abstract A novel graphene oxide nanosheet (GO) decorated with functional Cu-terephthalate (Cu-BDC-NH2) metal-organic framework (MOF) designed for hydrogen adsorption and storage. The composite framework was produced under low-frequency high-power ultrasound (20 kHz) waves to improve reaction time and yield. The obtained green powder was then characterized by SEM, XRD, FTIR, BET, and TGA analysis. Box-Behnken Design (BBD) was applied to optimize the reaction condition and GO content. Compared to pure MOF, our results revealed that the coupled effects of sonochemical synthesis and GO content improved both the production yield and hydrogen adsorption capacity of the composite framework. Also, it was observed that ultrasound waves improve the solvent exchange process for framework activation. Besides, the incorporation of GO enhances the chemical and thermal stability of the Cu-BDC-NH2 framework. The ultrasound wave and GO content increased the hydrogen adsorption capacity by improving the BET surface area, more active sites population and decreasing gas diffusion resistance by creating more defects.