09:30 〜 11:30
▲ [15a-P9-14] In-depth understanding of atomic and electronic structure properties of Ni-NP/MOF composites by synchrotron X-ray total scattering and high-resolution X-ray photoelectron spectroscopy
キーワード：Metal-organic frameworks, Pair distribution function, Hard X-ray photoelectron spectroscopy
Metal-organic frameworks (MOFs) are porous crystalline materials that are synthesized by assembling metal salts with organic ligands usually in appropriate solvents. MOFs are currently having much attraction as potential candidate for gas storage, separation, catalytic, optical and ion conduction. Among the various MOFs, M-MOF-74 (M= Mg, Mn, Fe, Co, Ni, Zn) has relatively large surface area and high density of unsaturated M2+ cation sites that can selectively interact with gases. Highly active Ni nanoparticles (NPs) in MOF were synthesized using novel hybridization method by partial thermal decomposition of a Ni-MOF-74, without any additional protecting agents or surfactants. The high energy X-ray diffraction (HEXRD) and hard X-ray photoelectron spectroscopy (HAXPES) of Ni-NP/MOFs were performed at BL04B2 and BL15XU at SPring-8, respectively. The pair distribution function (PDF) analysis uses HEXRD data to calculate local and long-range atomic structure via Fourier transform of total structure factors. The total correlation functions, T(r) show that the absence of the Ni-O contribution and the presence of Ni-Ni contribution for the Ni-MOF-74 at 400 oC are consistent with the reduction of Ni2+ to metallic Ni. In order to study the electronic structure, Ni 2p3/2 core-level spectra indicated the formation of Ni0 (852.7 eV), Ni2+ (853.9 eV) and Ni3+ (856.6 eV) for Ni-NP/MOFs, which suggested that Ni species was metallic Ni over Ni-NP/MOF composite. The atomic and electronic structural characterization of the Ni-NP/MOF provide useful information of the interaction of metal atom in this hybrid materials.