Synthesis And Gas (CH4, H2and CO2) Storage Properties Of Cu/4,4’-hpy MoFs

Metal organic-framework (MOFs) has been researched for nearly ten years. MOFs are made of metal and organic ligand, which have a special skeleton material like zeolite and can adjust pore sizes by changing organic ligand or a chain of the organic ligand. Due to its high porous and specific surface area, which is larger than zeolites with similar pores, MOFs are promising candidates for a wide range of applications in catalyst, gas storage, separation and biochemistry, etc. On one hand, seeking new energy is a better solution to the energy crisis. Methane and hydrogen are a clean fuel with higher calorific value and rich source so their use can ease the oil crisis to a great extent. On the other hand, the greenhouse effect does damage to the environment. However, the storage of the methane, hydrogen and carbon dioxide restricts more wide range of the use.Therefore, it is the key to seek a new material which can adsorb much methane, hydrogen and carbon dioxide. In this study,[Cu(SiF6)(4,4’-bpy)2], [Cu(bpy)(H2O)(BF4)(bpy)] and [Cr3(BTC)2] were synthesized through solution diffusion. Their physical properties were characterized by XRD, SEM, BET and TG. The stability and gas adsorption properties of these materials were tested by various characterization methods. The main contents and results are listed as follows:Firstly,[Cu(SiF6)(4,4’-bpy)2] was synthesized through the solution diffusion. The molar ratio of the reagents and synthesis temperature in the precursor were studied first and then crystallization time was investigated. It was found that the impact of temperature was more obvious and low temperature was more beneficial for synthesizing larger crystal, but when the temperature approached the freezing point, the crystalline structure of the materials generated under the same conditions worsened. The sample was characterizd by XRD, SEM, the liquid nitrogen adsorption and TG. In addition, the experiments of gas adsorption such as methane, hydrogen and carbon dioxide for this material were carried out. It was found that the material could store2.01wt%H2at77K at10bar and capture CH4and CO2which were2.02mmol/g and4.17mmol/g at298K and1.57mmol/g and3.72mmol/g at323K at10bar.Secondly,[Cu(bpy)(H2O)(BF4)(bpy)] was prepared by mixing distilled water of Cu(BF4)·6H2O and methanol of4,4’-bpy then heating the mixture for2hours-The molar ratio of the reagents and synthesis temperature in the precursor were studied first and then crystallization time was investigated. It was found that the impact of temperature was more obvious and high temperature was more beneficial for synthesizing larger crystal. The sample was characterizd by XRD, SEM, the liquid nitrogen adsorption and TG. In addition, the experiments of gas adsorption such as methane, hydrogen and carbon dioxide for this material were carried out. It was found that the material could store0.15wt%H2at77K at10bar and capture CH4and CO2which were0.21mmol/g and4.20mmol/g at298K at10bar.Finally, the purple [Cr3(BTC)2] was obtained through stirring Cr(CO)6and H3(BTC) in DMF solution in an environment with no water and oxygen-free. The molar ratio of the reagents and synthesis temperature in the precursor were studied first and then solvent quantity and crystallization time was investigated. The sample was characterizd by XRD, SEM, the liquid nitrogen adsorption and TG. In addition, the experiments of gas adsorption such as methane, hydrogen and carbon dioxide for this material were carried out. It could be found that the material could store1.3wt%H2at77K at10bar and capture CH4and CO2which were1.57mmol/g and3.20mmol/g at298K at10bar.