Wen Zhang, Ph.D., P.E., BCEE
Principal Investigator
Professor
Phone: (973) 596-5520
Fax: (973) 596-5790
Email: wen.zhang@njit.edu
Office Location: Colton Hall 211
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Nanoscale Hydrophobicity and Electrochemical Mapping Provides Insights into Facet Dependent Silver Nanoparticle Dissolution
Dr. Wen Zhang’s group in New Jersey Institute of Technology combined experimental and DFT approaches providing important and complementary information about faceted nanoparticle dissolution of Ag nanoparticles. Metal or metallic nanoparticle dissolution influences particle stability, reactivity, potential fate and transport. This work investigated the dissolution behavior for silver nanoparticles (Ag NPs) in three different shapes (nanocube, nanorod, and octahedron). The hydrophobicity and electrochemical activity at the local surfaces of Ag NPs were both examined using atomic force microscopy (AFM) coupled with scanning electrochemical microscopy (AFM-SECM). The surface electrochemical activity of Ag NPs more significantly affected the dissolution than the local surface hydrophobicity did. Octahedron Ag NPs with dominant surface exposed facets of {111} dissolved faster than the other two kinds of Ag NPs. Density functional theory (DFT) calculation revealed that the {100} facet elicited greater affinities toward H2O than the {111} facet. Thus, poly(vinylpyrrolidone) or PVP coating on the {100} facet is critical for stabilizing and prevent the {100} facet from dissolution. Finally, COMSOL simulations demonstrated consistent shape dependent dissolution as we observed experimentally. This study is supported by the NSF foundation (Award number: 1756444) and the NSF INTERN grant (Award number: 1836036).
马清泉：新泽西理工学院土木与环境工程系博士后。2022年12月博士毕业于新泽西理工学院，2019年1月和2016年6月于北航获得硕士和学士学位。主要研究方向为纳米材料的表征和理论计算，电催化膜的应用等。Qingquan Ma is a Postdoc in Environmental Engineering at NJIT. He received his Ph.D. degree at NJIT in Dec. 2022. He received his B.S. in 2016 and M.S. in 2019 from Beihang University. Mr. Ma’s research focuses on the synthesis and characterization of facet-dependent nano-catalysis, electrocatalysis, density functional theory (DFT) and multidisciplinary research in material characterization and electrochemical membrane processes.
纳米尺度表征亲疏水和电化学特性为不同形貌纳米银溶解提供新思路
第一作者：马清泉
通讯作者：张文
通讯单位：新泽西理工学院
DOI: https://pubs.acs.org/doi/full/10.1021/acs.jpclett.2c03917
文章摘要
新泽西理工学院土木与环境工程系张文教授课题组近期于The Journal of Physical Chemistry Letters发表研究论文。该研究结合先进的实验测试和理论计算为不同形貌纳米银溶解过程和机理提供新思路。金属纳米材料的溶解影响着纳米材料的稳定性、反应活性、潜在反应和运输。这项工作研究了三种不同形貌（纳米立方体、纳米棒和纳米八面体）的银纳米粒子的溶解行为。使用原子力显微镜（AFM）结合扫描电化学显微镜（AFM-SECM）对纳米银局部表面的疏水性和电化学活性都进行了表征和测试。结果表明纳米银的表面电化学活性比局部表面疏水性对溶解的影响更明显。纳米立方八面体银颗粒的主要表面暴露面为{111}，比其他两种纳米银的溶解速度快。密度函数理论（DFT）计算表明，{100}面比{111}面对水分子具有更强的亲和力。此外，{100}表面的聚乙烯吡咯烷酮（PVP）涂层对于稳定和防止{100}面的溶解至关重要。最后，COMSOL模拟结果也表明与我们在实验中观察到的形状的溶解趋势一致。这项研究得到了美国国家自然科学基金会基金会CBET基金（1756444）和美国国家自然科学基金会INTERN基金（1836036）的支持。
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