Phosphate Acid Functional Metal-Organic Frameworks Composite Material Adsorption Of Heavy Metal Ions And Oxygen Evolution Reaction

As emerging functional materials,metal-organic framework materials（MOFs）exhibit rich and diverse spatial structures,so that such materials have received extensive attention in academia and industry.In recent years,with the combination of MOFs and functional materials,post-synthetic modifications and MOFs-derived materials,more advanced highly active materials have been obtained.In this work,functionalized MOFs materials for the removal of heavy metal ions and electrocatalytic oxygen evolution reactions are designed and synthesized using post-synthesis modification.The research content is as follows:In this work,MOF-808（MOF-808-HPAA）adsorption materials modified by HPAA-modified MOF808（MOF-808-HPAA）were successfully synthesized by introducing 2-hydroxyphosphonoacetic acid（HPAA）into MOFs materials.HPAA was appropriately grafted into MOF-808,which was comprehensively characterized by infrared spectroscopy,nuclear magnetic hydrogen spectroscopy,X-ray photoelectron spectroscopy（XPS）spectroscopy and X-ray spectroscopy（EDS）.Functionalized MOF808（MOF-808-HPAA）indicated well selectivity for adsorbing Pb²⁺in aqueous.The adsorption capacity towards lead ions is of 157.4 mg/g with the removal rate as high as 99.9%.The adsorption data were fitted,found that the adsorption process of Pb²⁺conformed to the kinetic model and the Langmuir adsorption model.By investigating the adsorption and desorption processes of MOF-808-HPAA,the adsorption behavior of Pb²⁺ is mainly based on chemical adsorption.Based on the descriptions above,the transition metals Fe and Ni were consciously introduced into the framework of MOF-808-HPAA.Characterization via infrared spectroscopy,X-ray photoelectron spectroscopy（XPS）spectroscopy,and X-ray spectroscopy（EDS）revealed that Fe and Ni were successfully loaded in the skeleton of MOF-808-HPAA.By means of the modulation of the coordination environment surrounding the metal centers,the catalytic performance of MOFs in the electrocatalytic oxygen evolution reaction has been significantly enhanced.The results show that MOF-808-HPAA-FeNi performs a current density of 10 mA/cm2 at an overpotential of 288 mV in 1 mol/L KOH electrolyte,while the Tafel slope is as low as 36.2 mV dec-1.It is observed that MOF-808-HPAA-FeNi features good stability,of which the performance is superior to that of current commercial catalysts（RuO2）.