Mahmood Azhar, He Dequan, Liu Chuhao, Talib Shamraiz Hussain, Zhao Bolin, Liu Tianren, He Ying, Chen Lijuan, Han Dongxue, Niu Li
Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials and Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, 510006, P. R. China.
Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
Adv Sci (Weinh). 2024 May;11(17):e2309163. doi: 10.1002/advs.202309163. Epub 2024 Feb 29.
Tuning the crystal phase of alloy nanocrystals (NCs) offers an alternative way to improve their electrocatalytic performance, but, how heterometals diffuse and form ordered-phase remains unclear. Herein, for the first time, the mechanism for forming tetrametallic ordered-phase nanoplates (NPLs) is unraveled. The observations reveal that the intermetallic ordered-phase nucleates through crystallinity alteration of the seeds and then propagates by reentrant grooves. Notably, the reentrant grooves act as intermediate NCs for ordered-phase, eventually forming intermetallic PdCuIrCo NPLs. These NPLs substantially outperform for oxygen evolution reaction (221 mV at 10 mA cm) and hydrogen evolution reaction (19 mV at 10 mA cm) compared to commercial Ir/C and Pd/C catalysts in acidic media. For OER at 1.53 V versus RHE, the PdCuIrCo/C exhibits an enhanced mass activity of 9.8 A mg (about ten times higher) than Ir/C. For HER at -0. 2 V versus RHE, PdCuIrCo/C shows a remarkable mass activity of 1.06 A mg , which is three-fold relative to Pd/C. These improvements can be ascribed to the intermetallic ordered-structure with high-valence Ir sites and tensile-strain. This approach enabled the realization of a previously unobserved mechanism for ordered-phase NCs. Therefore, this strategy of making ordered-phase NPLs can be used in diverse heterogeneous catalysis.
调节合金纳米晶体（NCs）的晶相为提高其电催化性能提供了一种替代方法，但是，异质金属如何扩散并形成有序相仍不清楚。在此，首次揭示了形成四金属有序相纳米片（NPLs）的机制。观察结果表明，金属间有序相通过种子的结晶度改变成核，然后通过凹入沟槽传播。值得注意的是，凹入沟槽充当有序相的中间NCs，最终形成金属间PdCuIrCo NPLs。与酸性介质中的商业Ir/C和Pd/C催化剂相比，这些NPLs在析氧反应（10 mA cm时为221 mV）和析氢反应（10 mA cm时为19 mV）方面表现出色得多。对于相对于RHE为1.53 V的OER，PdCuIrCo/C表现出比Ir/C增强9.8 A mg的质量活性（高出约十倍）。对于相对于RHE为-0.2 V的HER，PdCuIrCo/C表现出1.06 A mg的显著质量活性，相对于Pd/C是其三倍。这些改进可归因于具有高价Ir位点和拉伸应变的金属间有序结构。这种方法实现了一种以前未观察到的有序相NCs机制。因此，这种制备有序相NPLs的策略可用于多种多相催化。
