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Synthesis of Nanoporous Materials Al-MCM-41 from Natural Halloysite
Yaling Xie,Aidong Tang,HUAMING YANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1
Nanoporous materials Al-MCM-41 with varying Si/Al molar ratios have been successfully synthesized from natural clay mineral halloysite nanotubes (HNTs). Hydrothermal treatment of acid-pretreated HNTs and NaOH solution resulted in the one-step synthesis of final nanoporous products by using surfactant. The effects of Si/Al molar ratios (7.7, 61.0 and 176.5) on the surface area, porosity and degree of structural order of Al-MCM-41 materials have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption measurements and Fourier transform infrared (FTIR) spectra techniques. The results indicated that Si/Al molar ratio had important effect on the characteristics of nanoporous materials, and Al-MCM-41 with an intermediate Si/Al molar ratio of 61.0 exhibited excellent characteristics with high degree of order, high surface area (SBET) of 1033 m2 /g and pore volume of 0.92 mL/g.
One-Step Synthesis of Rod-Shaped NiFe-MOF as a Highly Efficient Oxygen Evolution Catalyst
Dandan Zhang,Renxing Huang,Huaming Xie,Xingyong Liu,Ying Lei,Ming Pan 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8
Development of low-cost, highly active catalyst for efficient oxygen evolution reaction based on earth-abundant metals is still a great challenge. Here, we report that a rod-like bimetallic NiFe metal-organic framework (NiFe-MOF) can directly act as a highly efficient oxygen evolution reaction (OER) catalyst synthesized by a convenient-to-operate hydrothermal method. The rod-like NiFe-MOF can derive 10 mA cm -2 with a low overpotential of only 26 mV, and its Tafel slope is 40.82 mV dec -1, which is superior to that of monometallic Ni-MOF or Fe-MOF, and even can be comparable to that of RuO2. To identify the origin of enhancing OER activity, we resorted to X-ray diffraction, scanning electron microscope, transmission electron microscope, high resolution transmission electron microscopy image and nitrogen adsorption–desorption techniques and various electrochemical techniques to probe it gingerly. The results indicate that its high electrochemically active area and the synergistic effect of bimetallic node could be responsible for the surprisingly high catalytic performance of the NiFe-MOF. These results suggest that this kind of bimetallic MOF (NiFe-MOF) could be a promising electrocatalyst for oxygen evolution reaction.
Renxing Huang,Ying Lei,Dandan Zhang,Huaming Xie,Xingyong Liu,Honghui Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.9
It is highly pleasurable but challenging to develop economical and efficient catalysts for accelerating the oxygen reduction reaction (ORR) endowed with sluggish kinetics involved in renewable energy conversion and storage systems such as Zn-air batteries. Herein, N, P and Si tri-doped porous carbon (SiN-PA900) catalysts was prepared by a simple one-step pyrolysis strategy using the mixture of the ionic liquid formed by phytic acid (PA) and N-methylimidazole and tetraethyl orthosilicate (TEOS) as N, P, Si and carbon sources, and the PA as pore-foaming agent. The resulting SiN-PA900 shows favorable catalytic activity toward ORR with an onset potential of 0.94 V versus RHE, half-wave potential of 0.81 V versus RHE, robust stability and excellent tolerance for methanol in alkaline medium, which are comparable to those of the commercial 20% Pt/C. More impressively, the assembled primary Zn-air battery employing the SiN-PA900 as cathode catalysts can achieve a peak power density of 181.4 mW/cm2. Those encouraging properties could be attributed to a synergistic effect of the doped N, P and Si atoms in the carbon matrix, good surface wettability, high surface areas and hierarchical porous structures for sufficient contact and rapid transportation of the reactants in terms of composition and structures.