Lv Hao, Sun Lizhi, Zou Lu, Xu Dongdong, Yao Huiqin, Liu Ben
Jiangsu Key Laboratory of New Power Batteries , Jiangsu Collaborative Innovation Center of Biomedical Functional Materials , School of Chemistry and Materials Science , Nanjing Normal University , Nanjing , Jiangsu 210023 , China . Email:
School of Basic Medical Sciences , Ningxia Medical University , Yinchuan 750004 , China.
Chem Sci. 2018 Dec 11;10(7):1986-1993. doi: 10.1039/c8sc04696d. eCollection 2019 Feb 21.
Mesoporous noble metal nanocrystals have exhibited significant potential in electrocatalysis. However, it remains a big challenge to controllably synthesize sub-100 nm multimetallic mesoporous nanospheres (MNSs) with precisely tunable sizes and to further understand their size-dependent electrocatalytic performances. In this manuscript, a one-pot solution-phase strategy was developed for the formation of nanosized trimetallic PdAgCu MNSs with cylindrically open mesoporous nanochannels and continuous frameworks. The resultant Pd-based MNSs were precisely tailorable not only in terms of size (from 21 to 104 nm), but also in terms of elemental ratios and compositions (PdAgCu, PdAgPt, PdAgFe, PdPtCu, and PdCuRu). This system thus provided a facile yet straightforward means to evaluate the size effect of trimetallic MNSs in electrocatalysis. As an example, trimetallic PdAgCu MNSs with an average size of 36 nm exhibited the best activity of 4.64 A mg in the electrocatalytic ethanol oxidation reaction, 1.1-1.7 fold higher than that of MNSs with smaller or larger sizes and 5.9 fold higher than that of commercial Pd black catalyst. By means of kinetic studies, the size-dependent electrocatalytic performance can be ascribed to the optimization and balance between electron transfer and mass transfer processes inside PdAgCu MNSs. We expect that the size effect of multimetallic MNS nanocatalysts presented here may provide a general synthetic methodology for rational design of size-dependent nanocatalysts for a broad range of applications.
介孔贵金属纳米晶体在电催化领域已展现出巨大潜力。然而，可控合成尺寸精确可调的亚100纳米多金属介孔纳米球（MNSs）并进一步了解其尺寸依赖性电催化性能仍然是一项巨大挑战。在本论文中，我们开发了一种一锅法溶液相策略，用于制备具有圆柱形开放介孔纳米通道和连续骨架的纳米级三金属PdAgCu MNSs。所得的基于Pd的MNSs不仅在尺寸方面（从21到104纳米）可精确剪裁，而且在元素比例和组成方面（PdAgCu、PdAgPt、PdAgFe、PdPtCu和PdCuRu）也可精确剪裁。因此，该体系提供了一种简便直接的方法来评估三金属MNSs在电催化中的尺寸效应。例如，平均尺寸为36纳米的三金属PdAgCu MNSs在电催化乙醇氧化反应中表现出最佳活性，为4.64 A mg，比尺寸更小或更大的MNSs高1.1 - 1.7倍，比商业Pd黑催化剂高5.9倍。通过动力学研究，尺寸依赖性电催化性能可归因于PdAgCu MNSs内部电子转移和传质过程之间的优化与平衡。我们期望这里展示的多金属MNS纳米催化剂的尺寸效应可为广泛应用中合理设计尺寸依赖性纳米催化剂提供一种通用的合成方法。
