摘要
The coordination-directed strategy for fabricating customizable functional metal-organic frameworks(MOFs)offers a promising yet underexplored approach to optimizing their physicochemical properties for target applications.This work exploited the tunable characteristics of MOF structures to successfully synthesize a novel ternary MOF-on-MOF heterostructure(ZIF-67@MOF-74@PBA).The hybrid materials,composed of distinct components,enhance the structural integrity of the MOFs.The pyrolysis-derived bimetallic CoFeP nanoparticles anchored onto hierarchically porous carbon nanomaterials feature hollow structures with high site exposure,in situ grown CNTs that promote efficient mass and charge transport,and synergistic effects from multiple transition metals.The catalyst demonstrates excellent hydrogen evolution reaction(HER)activity(η_(10)=107 mV),oxygen evolution reaction(OER)activity(η_(10)=231 mV),and overall water splitting performance(1.544 V at 10 mA cm^(−2))in 1.0 M KOH,with remarkable long-term stability.Apparent activation energy measurements and density functional theory calculations confirm that the in situ integration of bimetals and phosphorus doping enhances O-O coupling in the OER and improves hydrogen adsorption/desorption in the HER,thereby optimizing overall catalytic efficiency.This synthesis strategy provides valuable insights and a new approach for the flexible design and practical application of multi-level MOF-on-MOF systems as high-performance electrocatalysts.
金属有机框架(MOFs)的可定制功能化策略为调控其物理化学性质提供了重要途径,但目前针对多组分MOF异质结构的系统性研究仍存在显著空白.本研究提出一种创新的配位导向合成策略,成功构建了三元ZIF-67@MOF-74@PBA异质结构,通过多组分协同作用显著提升了材料的结构稳定性.经热解转化后,该前驱体衍生出具有以下特征的双金属磷化物催化剂:(1)空心结构支撑的CoFeP双金属纳米颗粒,具有丰富的活性位点暴露;(2)分级多孔碳基质与原位生长的碳纳米管网络,实现高效传质与电荷转移;(3)过渡金属间的电子协同效应.电化学测试表明,该催化剂在1.0 M KOH电解液中表现出卓越的三功能催化性能:析氢反应(HER,η_(10)=107 mV)、析氧反应(OER,η_(10)=231 mV)及全水解反应(1.544 V@10 mA cm^(−2)),并具备良好的结构稳定性和电化学性能稳定性.结合表观活化能分析与密度泛函理论计算,揭示了磷掺杂双金属体系的协同机制:(i)OER过程中促进O-O键形成的能垒降低;(ii)HER过程中优化氢中间体的吸附自由能.本研究不仅为多级MOF异质结构的设计提供了普适性合成策略,更为开发高性能电催化剂提供了新的材料平台和理论依据.
基金
supported by the National Natural Science Foundation of China(21601137)
the Basic Science and Technology Research Project of Wenzhou,Zhejiang Province(G20240038)
the Yunnan Province Young and Middle-aged Academic and Technical Leaders Reserve Talent Project(202105AC160060)
the Special Basic Cooperative Research Programs of Yunnan Provincial Undergraduate Universities Association(202301BA070001-093 and 202401BA070001-002).
