Premaratne Gayan, Bhandari Silan, Walgama Charuksha, V Chikkaveeraiah Bhaskara, Jin Albert, Krishnan Sadagopan
Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
Department of Physical & Applied Sciences, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, Texas 77058, United States.
ACS Meas Sci Au. 2025 Apr 7;5(3):325-331. doi: 10.1021/acsmeasuresciau.5c00014. eCollection 2025 Jun 18.
We investigated the influence of particle size on the electrochemical behavior of FeO magnetite nanoparticles (MNPs) electrostatically adsorbed onto graphite electrodes modified with a preadsorbed poly-(ethylenimine) polycation layer. Three hydrodynamic sizes (50, 100, and 200 nm) were selected to assess size-dependent differences in electrochemical response using cyclic voltammetry under well-controlled adsorption and measurement conditions. The 50 nm MNPs exhibited the highest electroactive response and peroxidase-like electrocatalytic currents, which are consistent with greater surface area-to-volume ratios. Qualitative image analysis from atomic force microscopy and scanning electron microscopy revealed closer particle spacing and more extended surface contact for the smaller MNPs, in contrast to isolated aggregates formed by larger particles. These surface-level differences were reflected in the electrochemical signals, where the 50 nm particles yielded higher electroactive surface coverage. The study demonstrates how particle size and interfacial organization influence electrochemical readouts, underscoring the utility of correlating microscopy with electrochemical data to evaluate nanoparticle-based sensing interfaces.
我们研究了粒径对静电吸附在预吸附聚（乙二胺）聚阳离子层修饰的石墨电极上的FeO磁铁矿纳米颗粒（MNP）电化学行为的影响。选择了三种流体动力学尺寸（50、100和200纳米），以便在良好控制的吸附和测量条件下，使用循环伏安法评估电化学响应中与尺寸相关的差异。50纳米的MNP表现出最高的电活性响应和类过氧化物酶电催化电流，这与更大的表面积与体积比一致。原子力显微镜和扫描电子显微镜的定性图像分析显示，与较大颗粒形成的孤立聚集体相比，较小的MNP颗粒间距更近，表面接触更广泛。这些表面水平的差异反映在电化学信号中，其中50纳米的颗粒产生了更高的电活性表面覆盖率。该研究展示了粒径和界面组织如何影响电化学读数，强调了将显微镜与电化学数据相关联以评估基于纳米颗粒的传感界面的实用性。
