Li Lanqing, Gao Wei, Lei Min, Wen Dan
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072, P. R. China.
Chemistry. 2021 Jul 26;27(42):10966-10972. doi: 10.1002/chem.202101121. Epub 2021 Jun 1.
Post treatment of metal-organic frameworks (MOFs) is widely employed to develop efficient electrocatalysts with better catalytic properties. But the complex processes of post treatment generally led to the collapse of the original structures of MOFs, making the preservation of their pristine hierarchical porous structure a great challenge. Herein, we propose the strategy of alkali treatment of Ni-MOF to transform it into Ni(OH) with similar morphology and enhanced electrocatalytic properties for methanol oxidation reaction (MOR). The structure and electrocatalytic properties of as-obtained Ni(OH) nanostructured flowers were seriously depended on the alkali concentrations. As the result, Ni(OH) obtained from Ni-MOF treated by 0.25 M NaOH (noted as Ni(OH) -0.25) performs 1.5 and 2.5 times larger current density than those of Ni(OH) -0.025 and Ni(OH) -0.5 for MOR. Moreover, the electrocatalytic process and mechanism of MOR on the catalyst of Ni(OH) -0.25 are also revealed. Hence, this ex situ conversion strategy of alkali treatment for Ni-MOF uncovered the transformation of MOFs in alkaline solution and develops robust electrocatalyst for practical application of methanol fuel cells.
金属有机框架材料（MOFs）的后处理被广泛用于开发具有更好催化性能的高效电催化剂。但后处理的复杂过程通常会导致MOFs原始结构的坍塌，使其原始分级多孔结构的保留成为一个巨大挑战。在此，我们提出对Ni-MOF进行碱处理的策略，将其转化为具有相似形态且对甲醇氧化反应（MOR）具有增强电催化性能的Ni(OH)。所制备的Ni(OH)纳米结构花的结构和电催化性能严重依赖于碱浓度。结果，由0.25 M NaOH处理的Ni-MOF得到的Ni(OH)（记为Ni(OH)-0.25）在MOR中的电流密度分别是Ni(OH)-0.025和Ni(OH)-0.5的1.5倍和2.5倍。此外，还揭示了Ni(OH)-0.25催化剂上MOR的电催化过程和机理。因此，这种对Ni-MOF进行碱处理的异位转化策略揭示了MOFs在碱性溶液中的转变，并开发出用于甲醇燃料电池实际应用的稳健电催化剂。
