高效析氧反应催化剂Fe-MIL-101的制备及性能研究

Preparation and investigation of Fe-MIL-101 as efficient catalysts for oxygen evolution reaction

  • 摘要: 近年来,金属有机骨架(MOFs)逐渐用于析氧反应(OER)领域。在以往研究中,MOFs通常作为前驱体在高温下热解制备金属氧化物/多孔碳复合材料以提高OER性能。虽然金属氧化物/多孔碳复合材料显示出较高的催化活性,但是它们需要复杂的制备工艺和高温条件。因此,寻找一种不经过热解处理可以直接用作OER的高效能MOFs催化剂是有意义的。结果表明,以Co-ZIF-67/NF、Ni-MOF-74/NF和Fe-MIL-101/NF为OER的催化剂时,在1 mol/L KOH溶液中电流密度达到10 mA/cm2所需过电位分别为377、383和272 mV。Fe-MIL-101/NF的电荷转移电阻(Rct)为1.53 Ω,小于Co-ZIF-67/NF(32.40 Ω)和Ni-MOF-74/NF(43.78 Ω)。因此,随着催化剂的Rct逐渐增大,OER过程中的电荷传递能力降低,即快速的电荷转移速率是Fe-MIL-101/NF具有优异OER活性的主要原因。另外,不经热解处理的Fe-MIL-101/NF(272 mV)的OER活性明显高于商业RuO2/NF(302 mV),说明具有快速电荷转移速率的MOFs可以不经煅烧作为OER的高效催化剂。

     

    Abstract: In recent years, metal-organic frameworks (MOFs) have gradually been used in the field of oxygen evolution reaction (OER). In order to improve OER performance, MOFs are usually used as precursors to prepare metal oxide/porous carbon composites by pyrolysis at high temperatures in previous studies. Although metal oxide/porous carbon composites show high catalytic activity, they require complicated preparation processes and high temperature. Therefore, it is very significant to find a highly efficient MOFs, which can be directly used as OER without pyrolysis treatment. The results show that when Co-ZIF-67/NF, Ni-MOF-74/NF and Fe-MIL-101/NF are used as OER catalysts in 1 mol/L KOH solution, 377, 383 and 272 mV overpotentials are required to make the current density achieve 10 mA/cm2. The charge transfer resistance (Rct) of Fe-MIL-101/NF is 1.53 Ω, which is smaller than that of Co-ZIF-67/NF (32.40 Ω) and Ni-MOF-74/NF (43.78 Ω). Therefore, the higher of the Rct of the catalyst, the smaller of the charge transfer capacity in the OER process. Thus, the fast charge transfer rate is the main reason for the excellent OER activity of Fe-MIL-101/NF. In addition, the OER activity of Fe-MIL-101/NF (272 mV) without pyrolysis treatment is much higher than that of commercial RuO2/NF (302 mV), indicating that MOFs with fast charge transfer rate can be used as an efficient catalyst for OER without calcination.

     

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