Ru敏化MOF电子结构实现高效电解水

Ru sensitized MOF electronic structure for efficient water electrolysis

  • 摘要: 金属有机框架(MOF)材料因其强大的结构和功能可调性已成为极具潜力的电解水催化剂。然而,MOF催化剂由于自身较弱的电荷转移能力及有限的稳定性,其固有活性较低。因此,设计出兼具高活性与高稳定性的MOF催化剂仍是具有挑战性的难题。本文通过两步水热法成功合成了CoRu-BDC/NF(BDC:对苯二甲酸、NF:泡沫镍),Ru的引入调节了负载在NF上Co-BDC的内在活性,赋予了CoRu-BDC/NF丰富的活性位点、较快的电荷传输能力,有利于电催化性能的提升。结果表明,CoRu-BDC/NF在酸性环境中电流密度达到10 mA·cm−2时,HER过电位为34 mV,Tafel斜率为33 mV·dec−1。值得注意的是,在碱性条件下,当电流密度为10 mA·cm−2,HER和OER所需的过电位也仅为32 mV和280 mV,Tafel斜率分别为39 mV·dec−1 、49 mV·dec−1,均表现出优异的电催化性能。Ru的引入导致Co的电子结构和配位环境发生变化,使原始Co-MOF的表面积增加,为电化学反应提供了更好的电子转移平台,加快了电子在电极和电解液界面间的传递,进一步提升了电催化性能。

     

    Abstract: Metal-organic framework (MOF) materials have become potential catalysts for water electrolysis due to their strong structural and functional adjustability. However, the intrinsic activity of MOF catalyst is low due to its weak charge transfer ability and limited stability. Therefore, it is still a challenging problem to design MOF catalysts with high activity and high stability. In this paper, CoRu-BDC/NF(BDC: terylene acid, NF: nickel foam) was successfully synthesized by two-step hydrothermal method. The introduction of Ru regulated the intrinsic activity of Co-BDC loaded on NF, endowed CoRu-BDC/NF with abundant active sites and fast charge transport capacity, which was conducive to the improvement of electrocatalytic performance. The results show that when the current density of CoRu-BDC/NF reaches 10 mA·cm−2 in acidic environment, HER overpotential is 34 mV and Tafel slope is 33 mV·dec−1. It is worth noting that under alkaline conditions, when the current density is 10 mA·cm−2, the required overpotential of HER and OER is only 32 mV and 280 mV, and the slope of Tafel is 39 mV·dec−1 and 49 mV·dec−1, showing excellent electrocatalytic performance. The introduction of Ru leads to changes in the electronic structure and coordination environment of Co, increasing the surface area of the original Co-MOF, providing a better electron transfer platform for the electrochemical reaction, speeding up the transfer of electrons between the electrode and the electrolyte interface, and further improving the electrocatalytic performance.

     

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