Chen Ding, Yu Ruohan, Zhao Hongyu, Jiao Jixiang, Mu Xueqin, Yu Jun, Mu Shichun
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P. R. China.
The Sanya Science and Education Innovation Park of, Wuhan University of Technology, Sanya, 572000, P. R. China.
Angew Chem Int Ed Engl. 2024 Aug 26;63(35):e202407577. doi: 10.1002/anie.202407577. Epub 2024 Jun 30.
Interstitial filling of light atoms strongly affects the electronic structure and adsorption properties of the parent catalyst due to ligand and ensemble effects. Different from the conventional doping and surface modification, constructing ordered intermetallic structures is more promising to overcome the dissolution and reconstruction of active sites through strong interactions generated by atomic periodic arrangement, achieving joint improvement in catalytic activity and stability. However, for tightly arranged metal lattices, such as iridium (Ir), obtaining ordered filling atoms and further unveiling their interstitial effects are still limited by highly activated processes. Herein, we report a high-temperature molten salt assisted strategy to form the intermetallic Ir-B compounds (IrB) with ordered filling by light boron (B) atoms. The B residing in the interstitial lattice of Ir constitutes favorable adsorption surfaces through a donor-acceptor architecture, which has an optimal free energy uphill in rate-determining step (RDS) of oxygen evolution reaction (OER), resulting in enhanced activity. Meanwhile, the strong coupling of Ir-B structural units suppresses the demetallation and reconstruction behavior of Ir, ensuring catalytic stability. Such B-induced interstitial effects endow IrB with higher OER performance than commercial IrO, which is further validated in proton exchange membrane water electrolyzers (PEMWEs).
轻原子的间隙填充由于配体和集合效应，会强烈影响母体催化剂的电子结构和吸附性能。与传统的掺杂和表面改性不同，构建有序金属间化合物结构更有希望通过原子周期性排列产生的强相互作用来克服活性位点的溶解和重构，从而实现催化活性和稳定性的共同提高。然而，对于紧密排列的金属晶格，如铱（Ir），获得有序填充原子并进一步揭示其间隙效应仍然受到高活化过程的限制。在此，我们报道了一种高温熔盐辅助策略，以形成由轻硼（B）原子有序填充的金属间化合物Ir-B（IrB）。位于Ir间隙晶格中的B通过供体-受体结构构成了有利的吸附表面，在析氧反应（OER）的速率决定步骤（RDS）中具有最佳的自由能上坡，从而提高了活性。同时，Ir-B结构单元的强耦合抑制了Ir的脱金属和重构行为，确保了催化稳定性。这种B诱导的间隙效应使IrB具有比商业IrO更高的OER性能，这在质子交换膜水电解槽（PEMWEs）中得到了进一步验证。
