Hydrogen Adsorption Properties of Ag-doped ZIF-8

Abstract In this study, the effect of cation dope with Ag+ on the textural and hydrogen adsorption properties of ZIF-8 was investigated. The pre-synthesized ZIF-8 was doped with silver by treatment with 20 mL solutions containing 0.10, 0.25, 0.50, or 1.00 mmol of AgNO3 for 1 h. The structural characteristics of ZIF-8 and its Ag+-doped forms were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and N2 adsorption methods. The specific surface area and micropore volume of ZIF-8 samples with a high percentage of Ag+ cations were found to decrease slightly compared to pristine ZIF-8. The H2 adsorption capacities of the Ag+-modified samples, which decreased with increasing molarity, were measured at 77 K, with H2 retention values ranging from 0.365 and 1.254 wt %. The results of the study are explained in detail according to the Ag+ doping ratio. Changes in the BET and micropore surface areas were confirmed by N2 adsorption measurements, depending on the AgNO3 concentration used. Hydrogen adsorption isotherms were measured at 77 K up to 113 kPa. Of all the samples, ZIF-8_0.25 Ag exhibited the greatest hydrogen uptake capacity. The H2 adsorption findings indicated that Ag+ modification has the potential to enhance the hydrogen storage performance of ZIF materials. The differences in H2 adsorption capacity observed in this study can be attributed to the structural and textural effects of Ag+ doping.