What's the difference between uio-66 and uio-67

The low-temperature hydrogen storage property of UiO-66 synthesized by microwave method is higher than that of the material synthesized by traditional electric heating method, and the porous property and particle size of UiO-67 can be adjusted by adjusting the order of the addition of glacial acetic acid, and the CO2 adsorption property of UiO-67 obtained by microwave method is comparable to that of the material obtained by traditional method.　　UiO-66 nanocrystals with different sizes were successfully synthesized by solvent-heating method under microwave conditions using formic acid as a modifier in a short time and compared with UiO-66 crystals synthesized by conventional oven heating.The XRD and SEM characterization results showed that the modulation of formic acid increased the crystallinity and particle size of the crystals.The N2 physical adsorption studies showed that the UiO-66 crystals synthesized by different heating conditions had the phase and particle size of the UiO-66 crystals. UiO-66 crystals have similar microporous volumes, but the pore size distributions are significantly different. The results showed that the pore sizes of the microwave-synthesized samples were mainly concentrated at 0.82 nm and 1.10 nm, while the pore sizes of the samples synthesized by conventional oven heating were concentrated at 0.82 nm, 1.10 nm and 1.63 nm. The microwave-synthesized samples had smaller pore size distributions, which led to higher hydrogen adsorption at 77 K and 1 bar, and the mass hydrogen storage of samples MW-50 and MW-100 reached 1.83 wt% and 1.85 wt%, respectively, while that of CE-50 and CE-100 was only 1.57 wt% and 1.58 wt%.　　The UiO-67 materials were synthesized using glacial acetic acid as a moderator by the traditional electrothermal solvent-thermal method and microwave solvent-thermal method, and the synthesis time of the microwave method was greatly shortened compared with that of the traditional method, which was changed from 24 h to 2 h. With the same dosage of glacial acetic acid, the materials with different particle sizes, different crystalline properties, and different pore structures were obtained by adjusting the order of the glacial acetic acid additions. The CO2 adsorption of CE-0-3 and CE-3-0 reached 14 mmol/g at 298 K and 23 bar, and the CO2 adsorption of MW-1-2 and MW-2-1 also reached 12.8 mmol/g under the same conditions.