Synthesis, Characterization and Fabrication of Metal Organic Framework Composites for Adsorption and Electrochemical Applications

Abstract

Four metal organic frameworks [Zn(3-bpmh)(1,4-bdc)]n, [Cd(3-bpmh)(1,4-bdc)]n [C8H10CdO7]n.4H2O and C15H17N2NiO8 (Ni-BTC) were synthesized and characterized. N-doped nanostructured porous carbon materials coded as PCN920 and PCN900 were obtained through the thermal treatment of two frameworks [Zn(3-bpmh)(1,4-bdc)]n and [Cd(3-bpmh)(1,4-bdc)]n, respectively under argon gas environment, while the third compound [C8H10CdO7]n.4H2O had produced porous carbon material (PC900) through the same heating process as described earlier. The thermal evaporation of Zn metal yielded impressively high surface area carbon (PCN920), which is found to be 1171 m2g-1, while Cd metal elimination from [Cd(3-bpmh)(1,4-bdc)]n and [C8H10CdO7]n.4H2O had generated relatively low surface area carbon i.e. 407 m2g -1 for PCN900 and 877 m2g -1 for PC900. The derived carbon materials PCN920, PCN900 and PC900 had been utilized for the synthesis of bimetallic composites with 10% Pt and 5% second metal (Ni, Cu, Er) through polyol reduction procedure. The bimetallic composites synthesized from PCN920 are coded as Pt-Ni@PCN920, Pt-Cu@PCN920 and Pt-Er@PCN920, while that were prepared from PCN900 are coded as Pt-Er@PCN900 and Pt-Ni@PCN900 and Pt-Cu@PCN900. The PC900 used as support to prepare composites are Pt-Er@PC900 and Pt-Ni@PC900 and Pt-Cu@PC900. The layered cadmium framework [C8H10CdO7]n.4H2O was synthesized in crystal form and characterized through single crystal X-ray analysis. The infrared spectroscopy (IR), UV-Vis spectroscopy and terahertz time-domain spectroscopy (THz TDS) were performed for cadmium metal organic framework. The computational investigations of the framework were performed at B3LYP/LANL2DZ level in gas phase to support our experimental results. The terahertz time domain spectroscopy of [C8H10CdO7]n.4H2O was performed and its refractive index along with absorption coefficient in 0.2-1.3 THz range x were calculated. The Nonlinear optical properties analysis reveals that the first static hyperpolarizability of [C8H10CdO7]n.4H2O is 38 times greater than that of urea. All the composites have been characterized through PXRD, FTIR, RAMAN, BET, XPS, ICP, CHNS/O, EDX, SEM and TEM. The composites Pt-Ni@PCN920, Pt-Cu@PCN920, Pt-Er@PCN920, Pt-Er@PCN900, Pt-Ni@PCN900 and Pt-Cu@PCN900 were analyzed for three important electrocatalytic reactions oxygen evolution (OER), hydrogen evolution (HER) and oxygen reduction reactions (ORR), while Pt-Er@PC900, Pt-Ni@PC900 and Pt-Ni@PC900 were used as electrocatalysts to perform HER and ORR. The performance of Pt-Ni@PCN920 is found to be better than Pt-Er@PCN920 and Pt-Cu@PCN920 having the same substrate PCN920. Secondly, Pt-Er@PCN900 showed excellent performance for HER, OER and ORR than Pt-Ni@PCN900 and Pt-Cu@PCN900. The durability and stability of Pt-Er@PCN900 was marvelous. Thirdly, the performance of Pt-Er@PC900 was superb than Pt-Ni@PC900 and Pt-Cu@PC900. The Nickel metal organic framework, graphene oxide (GO) and their composites Ni-BTC@GO(1%), Ni-BTC@GO(2%), Ni-BTC@GO(3%), Ni-BTC@GO(4%) and Ni-BTC@GO(8%) were synthesized, characterized and used as adsorbents for denitrogenation of synthesized model fuel. The porosity of the composite was enhanced by adding GO as compared to pristine Ni-MOF. The composite material with enhanced porosity and high surface area was used as adsorbent to remove indole, pyridine and quinoline from synthesized model fuel. The adsorption results showed profound increase in the adsorption capacity of the Ni-MOF@GO composite as compared to the pristine MOF. The composites also showed good regenerative ability and reusability.